The paramo vegetation of the volcanic Ruiz-Tolima massif by JPZ.

1 The paramo vegetation of the volcanic Ruiz- Tolima massif* La vegetación de páramo del macizo volcánico Ruiz- Tolima** by/por

S. Salamanca, A.M. Cleef & J.O. Rangel Ch.

Dedicated to the memory of José Cuatrecasas Arumo.

Resumen Este capítulo presenta una clasificación, en unidades sintaxonómicas, de los tipos de vegetación del páramo, de acuerdo con el método propuesto por la Escuela Ziirich-Montpellier que fue retrabajado posteriormente por Westhoff & Van der Maarel (1973). Cleef (1981) aplicó por primera vez este método en Colombia. El nivel jerárquico básico del presente estudio es la asociación, definida como una unidad de vegetación que consiste en una comunidad de composición tlorística bien definida y de fisionomía uniforme y se encuentra bajo condiciones unifonnes de habitat. La asociación se define mediante una serie de levantamientos que tienen cierto número de especies en común (especies diagnóstico). El conjunto de datos analizados consta de 34 levantamientos efectuados a lo largo del transecto Parque Los Nevados (levantamientos TPN), de 71 levantamientos efectuados por A.M. C1eef en 1980 en colaboración con el primer autor (levantamientos AMe) y finalmente de 164 levantamientos realizados por el primer autor en 1980 (parte en conjunto con E.H. Kloosterman y C. Kloosterman, levantamientos SS) y en 1982. Estos datos se ordenaron en tablas de constancia (Miiller Dombois & Ellenberg 1974) correspondiendo cada una a una formación vegetal diferente. Se establecieron grupos de levantamientos teniendo en cuenta las similaridades y disimilaridades en cuanto a composición de especies. Con base en los grupos definidos se elaboró una tabla síntesis (tabla romana), en la cual la constancia de una determinada especie dentro de un grupo de levantamientos se expresa en cinco clases (cada una del 20%) las cuales se designan mediante numerales romanos. Esta tabla síntesis (Tabla 1) que se ordenó mediante el método Twinspan (HillI979) muestra las afinidades tlorísticas entre los grupos y se utilizó para definir las unidades fitosociológicas finales. Para la nomenclatura de los sintaxa se empleó la metodología propuesta en la segunda edición del Código de Nomenclatura Fitosoci-

* Tables 1,2,3,4

** Tablas

1,2,3,4

and 6 on CD in the back ofthis volume. Y 6 en CD al final de este volumen.

The paramo vegetation

ológica (Barkman et al., 1986). En la definición de los tipos de vegetación se tnvieron en cuenta las clasificaciones disponibles de otras vegetaciones altoandinas y de páramo. Este estndio considera principalmente los tipos de vegetación del páramo propiamente dicho y el superpáramo. También se suministra una referencia rápida a los bosques altoandinos que bordean los páramos. La distribución espacial esperada en cintnrones altitndinales se encuentra un poco distorsionada debido al carácter volcánico del área. Kloosterman (capitnlo15, este volumen) provee una descripción detallada del paisaje en relación con la distribución espacial de la vegetación de páramo en el Parque Los Nevados. A continuación se citan los sintaxa descritos (la mayoría descritos por Salamanca, Cleef & Rangel 1992) al interior de cada una de las seis formaciones vegetales principales: Gynoxyo-Polylepidetum sericeae, Baccharido tricuneatae-Hypericetum laricifolii, y Pentacalietum vernicosi Cleef 1981. Además se tipificaron dos comunidades, de Gynoxys sp., y de Escallonia myrtilloidesAciachne acicularis dentro de los bosques enanos de páramo y los matorrales (Tabla 2). Calandrinio acaulis-Calamagrostietum rectae, Calamagrostietum ejJitso-rectae, Festuco dolichopihyllae-Calamagrostietum ejJitsae y Espeletio hartwegianae-Calamagrostietum effusae dentro de los pajonales del páramo propiamante dicho (Tabla 3). Wernerietum crasso-humilis, Floscaldasio hypsophilae-Distichietum muscoides, Carici peucophilae-Wernerietum crassae y Gentianello dasyanthae-Plantaginetum rigidae, dentro de los cojines de plantas vasculares (Tabla 4). Muhlenbergietum cleejii Cleef 1981 corr. Cleef, Aciachnetum acicularis Vareschi 1953 corro Salamanca, Cleef & Rangel, y Agrostio breviculmis-Lachemilletum orbiculatae, dentro de los prados (Tabla 5). Cerastio floccosi-Pentacalietum gelidae, Elaphoglosso mathewsiiMuehlenbecldetum vulcanicae, Racomitrio crispuli-Lachemilletum nivalis, Thamnolio vermicularisRacomitrietum crispuli, Senecioni latiflori-Calamagrostietum ligulatae, y Senecioni canescentis-Cerastietum jloccosi, dentro de las comunidades subnivales del superpáramo (Tabla 6). Lupino alopecuroidesAgrostietum araucanae, Baccharido caespitosae-Agrostietum araucanae, y Diplostephio eriophoro-Loricarietum colombianae, dentro del pastizal azul del superpáramo (Tabla 7). La tabla sinóptica 4 muestra las interrelaciones entre los 31 sintaxa definidos para la vegetación de páramo del Parque Los Nevados. En el presente estudio se describen también por primera vez algunos sintaxa de la vegetación zonal del páramo del Parque Los Nevados a nivel de alianza, orden y clase. Son: Espeletio-Calamagrostietea rectoeffusae cl. nov., Calamagrostietalia recto-effusae ord. nov., Cerastio subspicatae-Calamagrostion rectae al. nov., Festuco dolichophyllae-Calamagrostion effusae al. nov., Agrostiofoliatae-Cerastionfloccosae al. nov., y Festuco breviaristatae-Agrostion araucanae al. nov. Finalmente se propone una zonificación altitndinal de la vegetación zonal para la palie alta del transecto TPN. En el flanco oeste del volcán de Santa Rosa se encuentra la secuencia más completa de la vegetación zonal del páramo. En el páramo propiamente dicho, los pajonales más extendidos son aquellos pelienecientes a la asociación Calandrinio acaulis-Calamagrostietum rectae . La distribución espacial de este tipo de vegetación es disimétrica, pues alcanza altitndes un poco menores en los flancos exteriores de los volcanes. El límite superior de los pajonales de páramo propiamente dicho que pertenecen a la asociación Calamagrostietum effuso-rectae, se encuentra a una altitud mayor en la vertiente este del volcán de Santa Rosa que en la vertiente oeste. Por otra parte, en la vertiente oeste del volcán de Santa Isabel estos pajonales así como los que pertenecen a la asociación Espeletio hartwegianae-Calamagrostietum effusae, se encuentran restringidos a una pequeña extensión, mientras que los pajonales azonales que pertenecen a la asociación Festuco dolichophyllae-Calamagrostietum effitsae, ocupan un área mayor. El límite altitndinal entre el superpáramo alto y bajo es difuso. De 4400 m hacia arriba dos asociaciones que pertenecen a la vegetación subnival, el Senecioni canescentis-Cerastietumfloccosi y el Senecioni canescentis-Calamagrostietum ligulatae se encuentran en el mismo rango altih¡dinal o incluso a más baja altitud que algunas asociaciones como el Lupino alopecuroides-Agrostietum araucanae y el Diplostephio eriophoro-Loricarietum colombianae, que pertenecen al pastizal azul del superpáramo bajo. El Diplostephio eriophoro-Loricarietum colombianae se encuentra bastante extendido en la vertiente oeste del volcán de Santa Isabel (de 4350 a 4470 m) mientras que ocupa solamente una pequeña franja a ambos lados del volcán de Santa Rosa. La línea arbórea se encuentra alrededor de 3800 m en las vertientes externas tanto del volcán de Santa Rosa como del de Santa Isabel. Por otra parte en las vertientes internas de los dos volcanes, las cuales terminan en el Lago de Otún a 3900 m, se encuentra una vegetación azonal de bosques enanos de páramo pertenecientes a la comunidad de Aciachne acicularis-Escallonia myrtilloides. En cuanto a la vegetación azonal, el Gentianello dasyanthae-Plantaginetum rigidae, es el tipo de vegetación más extendido dentro de las turberas de plantas en cojín. Se encuentra entre 3700 y 4200 m en la

La vegetaciรณn de pรกramo

vertiente este del volcรกn de Santa Isabel y entre 4100 y 4200 m en la vertiente este del volcรกn de Santa Rosa. El Floscaldasio hypsophilae-Distichietum muscoides, mucho mรกs restringido en extensiรณn, se encuentra a 4150 m en el lado oeste del volcรกn de Santa Rosa y a 4350 m en el lado este del volcรกn de Santa Isabel, cerca de la transiciรณn con el superpรกramo. En la vertiente oeste del volcรกn de Santa Isabel a 4200 m, se encuentran pequeรฑos parches de turberas pertenecientes al Wernerietum humilis var. de Distichia muscoides. Por otra parte el Carici peucophilae-Wernerietum crassae se registrรณ a 3800 m en la vertiente este del volcรกn de Santa Isabel. A 4300 m se registrรณ un bosque enano perteneciente al Gynoxyo-Polylepidetum sericeae en la vertiente oeste del volcรกn de Santa Isabel. Entre 3830 y 3900 m se encuentran bosques enanos del Baccharido tricuneatae-Hypericetum laricifolii en la vertiente oeste del volcรกn de Santa Isabel. Por otra parte el Pentacalietum vernicosi se registrรณ a 4340 m tambiรฉn en la vertiente oeste del volcรกn de Santa Isabel y a 4350 m en la vertiente este del mismo. Los prados azonales pertenecientes a la asociaciรณn Muhlenbergietum cleefii se registraron solamente en un levantamiento en la mรกrgen oeste del Lago de Otรบn a 4000 m. El Aciachnetum acicularis subass. lupinetosum microphylli, se registrรณ en la vertiente este del volcรกn de Santa Rosa a 4050 m. En la vertiente oeste del volcรกn de Santa Isabel los tipos de vegetaciรณn mรกs altos pertenecen a dos asociaciones diferentes de la vegetaciรณn subnival en el superpรกramo alto. El primero registrado a 4540 m es el Senecioni canescentis-Cerastietum./loccosi. Un poco mรกs abajo, a 4400 m se encuentra la asociaciรณn Senecioni latiflori-Calamagrostietum ligulatae. El Diplostephio eriophoro-Loricarietum colombianae, perteneciente al pastizal azul del superpรกramo bajo se encuentra a 4450 m. Entre 4350 y 4400 m se encuentra otra asociaciรณn perteneciente al pastizal azul del superpรกramo bajo, el Lupino alopecuroidesAgrostietum araucanae. La transiciรณn al pรกramo propiamente dicho se encuentra alrededor de 4400 m. Entre esta altitud y 4150 m se encuentran los pajonales del pรกramo propiamente dicho pertenecientes a la asociaciรณn Calandrinio acaulis-Calamagrostietum recta e . A 4140 m se encuentran los pajonales azonales del Festuco dolichophyllae-Calamagrostietum effusae. En la vertiente este del volcรกn de Santa Isabel el tipo de vegetaciรณn mรกs alto (a 4475 m) pertenece al Lupino alopecuroides-Agrostietum araucanae. Esta vegetaciรณn se extiende hasta 4400 m. La transiciรณn al pรกramo propiamente dicho se encuentra alrededor de 4350 m. Los pajonales del Calandrinio acaulis-Calamagrostietum rectae, del pรกramo propiamente dicho alto se encuentran entre 4125 y 4315 m. En este mismo rango altitudinal tambiรฉn se encuentran algunos pajonales pertenecientes al Calamagros(ietum e{filso-rectae y al Espeletio hartwegianae-Calamagrostietum effusae. El tipo mรกs alto de vegetaciรณn registrado en la vertiente oeste del volcรกn de Santa Rosa (a 4550 m) pertenece a la asociaciรณn Lupino alopecuroides-Agrostietum araucanae. Entre 4390 y 4460 m se encuentra el pastizal azul del Diplostephio eriophoro-Loricarietum colombianae. La transiciรณn al pรกramo propiamente dicho se encuentra alrededor de 4400 m. Entre 4250 y 4330 m se encuentran los pajonales del Calandrinio acaulis-Calamagrostietum rectae. Entre 4050 y 4175 m se encuentran los pajonales del Calamagrostietum effilso-rectae. El pajonal azonal perteneciente a la asociaciรณn Festuco dolichophyllae-Calamagrostietum effusae, se encuentra entre 3850 y 3960 m. En la vertiente este del volcรกn de Santa Rosa la vegetaciรณn mรกs alta pertenece a la asociaciรณn Senecioni canescentis-Cerastietum./loccosi, de la vegetaciรณn subnival y se encuentra a 4400 m. A esta misma altitud e incluso unos metros por encima, se encuentran el Lupino alopecuroides-Agrostietum araucanae, y el Diplostephio eriophoro-Loricarietum colombianae, ambos del pastizal azul. Los primeros pajonales del pรกramo propiamente dicho, pertenecientes al Calandrinio acaulis-Calamagrostietum rectae, se encuentran tambiรฉn a 4400 m, y descienden hasta 4200 m.

Introduction and methods The word "paramo" has been commonly used since the Spanish Conquest. For the conquerors those lands, high up in the mountains ofthe New World, had many similarities with the remote high areas in the mountains ofthe Iberic Peninsula. In northern Peru, the paramo is called "jalea". In the rest of Peru, Bolivia, northern Argentina and Chile the dry open vegetation type above the upper forest line is termed "puna" in the Quechua language. Although in recent European and American literature the open vegetation above the upper forest hne is often referred to by "tropical alpine", because ofthe equatorial Andean setting, the

The paramo vegetation

Table 1. 8ynoptic table showing the relationship among the different paramo syntaxa (on CD in the back of this volume). - Tabla sin贸ptica que muestra las relaciones entre los diferentes sintaxa del p谩ramo (en CD al final de este volumen).

A1 A2 A3 81a 81 b 82 83 84 F1 F2 F3 F4 F5 P1 P2a P2b P3 81a 81 b 82 83 84 85 86 87 T1a T1 b T2 T3 T4a T 4b

Lupino alopecuroides-Agrostietum araucanae ass. nov. Baccharido caespitosae-Agrostietum araucanae ass. nov. Diplostephio eriophori-Loricarietum colombiana e ass. nov. Calandrinio acaulis-Calamagrostietum recta e ass. nov. varo typicum varo nov. Calandrinio acaulis-Calamagrostietum rectae ass. nov. varo of Espeletia hartwegiana ssp. centroandina varo nov. Calamagrostietum effuso-rectae ass. nov. Festuco dolichophyllae-Calamagrostietum effusae ass. nov. Espeletio hartwegianae-Calamagrostietum recta e ass. nov. Gynoxyo-Polylepidetum sericeae ass. nov. Dwarf forests (bosques enanos) of Gynoxys sp. Dwarf forests (bosques enanos) of Aciachne pulvinata and Escallonia myrtilloides Baccharido tricuneatae-Hypericetum laricifolii ass. nov. Pentacalietum vernicosi Cleef 1981 Muhlenbergietum cleefii Cleef 1981 Aciachnetum acicularis subass. typicum subass. nov. Aciachnetum acicularis subass. lupinetosum microphyllae subass. nov. Agrostio breviculrnis-Lachemilletum orbiculatae Cleef 1981 Cerastio f1occosi-Pentacalietum gelidae ass. nov. varo inops varo nov. Cerastio f1occosi-Pentacalietum gelidae ass. nov. varo ofStereocaulon vesuvianum varo nov. Elaphoglosso mathewsii-Muhlenbeckietum vulcanicae ass. nov. Racomitrio crispuli-Lachemilletum nivalis ass. nov. Thamnolio vermicularis-Racomitrietum crispuli ass. nov. Senecio latiflori-Calamagrostietum ligulatae ass. nov. Senecio canescentis-Cerastietum f1occosi ass. nov. 8ubnival vegetation complex (complejo de vegetaci贸n subnival) Wernerietum humilis ass. nov. varo of Hypochoeris sessiliflora varo nov. Wernerietum humilis ass. nov. varo of Distichia muscoides varo nov. Floscaldasio hypsophilae-Distichietum muscoides Cleef 1981 Carici peucophilae-Wernerietum crassae Cleef 1981 var of Cotula mexicana varo nov. Gentianello dasyanthae-Plantaginetum rigidae ass. nov. subass. typicum subass. nov. Gentianello dasyanthae-Plantaginetum rigidae ass. nov. subass. brometosum lanatae subass. nov.

word "paramo" is preferred here. Moreover, the word "paramo" is gaining wider use and refers exactly to the equatorial cold and humid high mountain vegetation of South and Central America, which is largely derived from the tropical Andean stock. The aim ofthis chapter is to provide a classification, in syntaxonomical units, ofthe vegetation types of the paramos in the Ruiz- Tolima volcanic massif according to the principIes and method ofthe phytosociological school ofZurich-Montpellier (Westhoff & Van der MaareI1973). Ihis method was first applied, and detailed, in Colombia for the paramo vegetation (Cleef 1981). The basic hierarchicallevel used is the 'association'. Ihis is defined as a vegetation unit consisting of a community within an uniform environment with well-defined floristic composition and an uniform physiognomy. The association is defined by one or more relev茅s, which share a number of character species (i. e. diagnostic species). A member of an association should be recognizable in the field by the presence of a specific group of diagnostic species.

La vegetación de páramo

The paramo vegetation data set analyzed consists of 34 relevés made in 1980 along the Parque Los Nevados transect (TPN relevés; data are presented in the appendix after chapter 3), 71 relevés made by A.M. Cleef(AMC relevé s), mostIy in collaboration with the first author in 1980 and, finally, 164 relevé s made by the first author in 1980 in part together with E.H. Kloosterman and C. Boonen and in 1982 (SS relevés) . First of all this data set was ordered into constancy tables (sensu Miiller Dombois & Ellenberg 1974), one per vegetation formation. Relevé groups were established on the similarities in species campo sitian using TWINSP AN (Hill1979). Based on al! the defined groups, a summary table was constructed, where the constancy of a given species within a group ofrelevés is expressed in five c1asses (each 20%) designated by Roman numerals. This summary table (Table 1), which was ordered with TWINSPAN, shows the floristic affinities between the groups and was used to define the final phytosociological units. For selecting the names of the syntaxa, the methodology proposed in the second edition of the Code of Phytosociological Nomenc1ature by Barkman et al. (1986) was followed. With regard to the c1assification of the Ruiz- Tolima paramo vegetation types, the c1assifications already available from paramo and high Andean vegetation elsewhere were taken into account. The first text (in English) of the present study was part of a photocopied manuscript, which was used by the first author for the defence ofher Ph.D. thesis at the University of Amsterdam (Salamanca 1991). Later this study was translated in Spanish (Salamanca 1992). We consider the printed version of Salamanca (1992), and especially chapter 4 (Salamanca, Cleef & Rangel 1992) as the formal reference publication for the validation of the different syntaxa described. Complementary to earlier editions ofSalamanca (1991, 1992), we have updated the information and corrected taxonomical plant names, as far as necessary, with reference to the earlier published syntaxa. In addition we have described in this study also a number of syntaxa above the level ofthe association (alliance, order, c1ass), especially for the zonal paramo vegetation. This study focuses on the zonal, and most common azonal, vegetation types within the grassparamo and the superparamo. A quick reference to the uppermost high Andean forests, bordering the paramo, is also provided. The expected spatial distribution of the vegetation in altitudinal belts is somewhat distorted by the volcanic character of the area. Kloosterman et al. (this volume) provide a detailed description of the landscape in relation to the spatial distribution of the paramo vegetation of the Parque Los Nevados. As to the correct spelling of the names of the plant species reference can be made to Luteyn (1999). We did not distinguish between Werneria Kunth and Xenophyllum V.A. Funk in this study and maintained all species belonging to both genera under Werneria.

The paramo concept Several papers dealing with physiognomic and floristic descriptions, as well as with phytosociological classifications, of the paramo vegetation have been published. The first modern studies were published by Cuatrecasas (1934,1954,1958,1968,1979,1980). Cleef(e.g. 1978, 1979a, 1979b, 1980a, 1980b, 1980c) studied the general physiognomy and the altitudinal sequence of the paramo vegetation, as well as the campo sitian and the phytogeographical position of the vascular flora of the paramos of the Colombian Cordillera Oriental. Cleef (1981) published a rather complete phytosociological study on the paramo vegetation of the Colombian Cordillera Oriental. In the case of the vegetation of the Parque Los Nevados Cleef et al. (1983) provided the first approach (after Cuatrecasas 1934) on the reconaissance ofthe paramo and Andean forest vegetation types as well as information on the altitudinal zonation of the Parque Los Nevados vegetation. In a similar study, Cleef & Rangel (1984) c1assified the paramo vegetation along the Buritaca transect, located in the Sierra Nevada de Santa Marta. Rangel & Franco (1985), Sturm & Rangel (1985), Rangel & Lozano (1986), Franco et al. (1986), Duque & Rangel (1989), Sánchez & Rangel (1990), Restrepo & Duque (1992) and Becking et al. (1997) also provided

The paramo vegeta tia n

phytosociological studies ofthe paramo vegetation in different localities ofthe three Colombian Cordilleras. Studies concerning the structure, biomass, productivity and nutrient status ofbunchgrass paramos in the Eastern Cordillera are found in Lutz & Vader (1987) and Beekman & Verweij (1987). For the volcanic Central Cordillera more recently also in Hofstede (1995) for the Parque Los Nevados area. Ferwerda (1987) and Van Groen (1987) discussed the influence of agriculture and burning on natural bunchgrass paramos in the Eastern Cordillera. Verweij (1995) studied patterns ofburning and grazing for the Los Nevados National Park. A vegetation map based on photo interpretation and field control of the Parque Los Nevados is presented in Kloosterman et al. (chapter 5, this volume). Other studies concerning different types ofparamo vegetations have been published for northern Ecuador, Peru, Venezuela, Panamá and Costa Rica. See for references Luteyn (1999). In the present study, the concepts of zonal and azonal vegetation follow Walter (1979). Vegetation types mainly depending on the macroclimate are considered as zonal, while others, which strongly depend on local edaphic factors, are considered as azonal. However, it was not always easy to decide whether some vegetation types should be ranked as zonal or azonal; see Cleef (1981) for further details.

Altitudinal zonation and physiognomy Cuatrecasas (1958, 1968) described three major zones ofparamo vegetation in the Colombian Andes, which can be distinguished by means of their physiognomy and floristics. These zones are; the subparamo, including scrub paramo, just above the upper forest line; the paramo proper, or grassparamo, and the superparamo, just below the ice cap. Furthermore, Cleef (1979a, 1980b, 1981) subdivided each of these zones in a higher and a lower subzone for the Colombian Eastern Cordillera. This altitudinal zonation is although valid for the Colombian Eastem Cordillera. In the RuizTolima volcanic massif of the Central Cordillera no proper shrubby subparamo vegetation is present, except perhaps for the area North ofthe Tolima Volcano. In this area Cuatrecasas (1934) described two types of shrubby vegetation referred to as 'Vaccinietum floribundi' (3500-3600 m) and 'Espeletietum hartwegianae-Hypericeti laricifoliosum' (3450-3600 (3800) m (see Cuatrecasas, chapter 4, this volume). Cleef et al. (1983) and Van der Hammen & Cleef (1986), concluded that the near absence of a subparamo belt in this vo1canic massif can be attributed to the absence of a number oftaxa which characterize the subparamo zone in the Colombian Eastem Cordillera. In the Parque Los Nevados, patches of high Andean dwarf forests are found between 3600 to 3900 (3800) m. The grassparamo is situated from 3800 (3900) to 4400 (4300) m and the superparamo occurs from 4300 to 4800 m. The nival zone starts around 4800 m, albeit with many exceptions due to local circumstances. See also the vegetation map ofKloosterman et al. (Chapter 5, this volume). Elsewhere in the Colombian Andes, e.g. Sierra Nevada de Santa Marta (Cleef & RangeI1984), Westem Cordillera (Cleef et al. in prep.) and near Popayán (Becking et a1.l997) subparamo scrub is patchy. This apparently results from the steep slopes and small ridges. The Venezuelan paramos cover an altitudinal range from 3000 to 4800 m (Monasterio 1980). The paramo region is subdivided into two altitudinal zones; the transition being place at 4000 m. The lower zone, 'Paramo Andino' broadly corresponds with the Colombian subparamo and grassparamo. The higher zone ('Páramo desértico' and 'Desierto Periglacial') broadly correspond to the superparamo belt. Vegetation types and tife forms of the upper grassparamo and superparamo of the Mérida Andes have recently been studied by Berg (1998). Shrubs of Ericaceae and/or Compositae in contact with the open paramo vegetation, which could be regarded as a kind of subparamo vegetation, have also been described for Venezuela (Monasterio, f.c.; Vareschi 1980).

La vegetación de páramo

Harling (1979) defined three altitudinal paramo vegetation belts for Ecuador; e.g. grassparamo (3400-4000 m), shrub and cushion paramo (4000-4500 m) and the desert paramo (mainly above 4500 m). Acosta-Solís (1984) established the following altitudinal zones for the Ecuadorian paramos: the low paramo from 3300 m to 4000 m; the "middle paramo" from 4000 to 4500 m, and the high paramo from 4500 m upwards. This corresponds rather well with the division proposed by Cuatrecasas (l.c.) for the Colombian paramos. A narrow belt (comparable with what Harling (1979) and Ramsay (1992) described as cushion paramo for Ecuador), where the tussocks of Poaceae are intermingled with vascular cushion plants, is present around 4000-4100 m on the West slope of the Ruiz Voleano. The zonal paramo vegetation of Ecuador has been studied by Ramsay (1992).

High andean forests The high Andean forests are the altitudinally highest forests in the Andes. They are found along the upper forest line and locally as isolated stands in the paramo belt. Grubb (1977) differentiated these forests, consisting of small-sized trees, as subalpine rain forests (SARF), occupying a propel' altitudinal position as compared to the upper montane rain forests (UMRF). However, in our opinion, they belong to the upper montane rain forest belt, differing only in stature, species composition (fewer species), and slower nutrient/water cycling processes because oflower mean annual temperature. See for references Grubb (1977), Veneklaas (1990), Bruynzeel & Veneklaas (1998), Cavelier (1996), Marrs et al. (1988) and van del' Hammen (final chapter, this volume). The upper forest limit, even under equatorial-montane conditions, is not constant. Also, it often has been subject to strong human influence. As a result, the distributions of forest and paramo vegetation intermingle. For example, in the TPN transect area the altitudinal variation is between 3600 and 4000 m. Paleoecological studies have shown that some 5000-6000 years B.P. the forest line reached a couple ofhundred meters higher than today (Van del' Hammen & González 1960, 1965, Van del' Hammen et al. 1973; Van del' Hammen 1974, 1979; Kuhry et al. 1983; Melief 1985; Salomons 1986). They have also shown the forest line to occur much lower, around 2000 m, during the Late Pleniglacial. The present uppermost forest limit is situated at c. 3800 m in the Ruiz- Tolima massif. Paleoecological studies in the El Bosque locality (Kuhry et al. 1983; Kuhry 1988) have shown no changes in this position during the last 3000 years. Nevertheless, the uppermost forests in the area today show a strong human impact and have been partially destroyed (see also Verweij & Beukema 1992). Monasterio (1980), considering the patchy distribution of the forest limit in Venezuela, surmises that some ofthe forests which are found within the borders ofthe paramo are high Andean forest refuges. The withdrawal downslope ofthe forests is, according to her, due to competition of diverse species of Espeletia for the same habitats. Regarding todays presence of puna vegetation in the Peruvian and Bolivian altiplanos, Ellenberg (1979) suggests that the patchy distribution of Polylepis and Escallonia woodland above the present timberline, highlights the ability offorest vegetation to grow beyond their recognized environmentallimit. Therefore, they are considered as relicts of more favourable past climatic conditions. Indeed Ellenberg (1979) asserts that paramo and puna grasslands cannot be regarded as climax vegetation, but are caused by deforestation, burning and grazing. Detailed discussion on this account is given by Holdridge (1947), Weberbauer (1945), Ellenberg (1959,1979), Tosi (1960), Koepcke (1961), Scott (1974), Unzueta (1975) and Beck & Ellenberg (1977). Recently, Laegaard (1992) also suggested that the lower paramo belt in Ecuador largely results from deforestation of the high Andean Polylepis forest. The paramo-like bunchgrasslands replace upper Andean forests. In OUT study area this replacement also might have occurred in some local patch-

The paramo vegetation

es. Near the forest line, patches ofparamo bunchgrasslands, dominated by Festuca dolichophylla, might have presumably supported a high Andean forest, in earlier days. The so-called "socaló" agrosystem, facilitating access of cattle to the forest by selective felling and by stimulating grawth of the herb layer, might have also contributed to influencing the altitudinal position of the upper forest line replacing the open patches oftrees by grazed, open vegetation (Verweij & Beukema 1992; Kok et al. 1995). The high Andean forests, just below the paramo belt in the study area, originally classified as the Hesperomeletum lanuginosae (Cuatrecasas 1958) are found on the southern slope of the Tolima Volcano, falllargely within the altitudinal range of 3300-3800 m (see also Chapters 2 and 4 this volume). Among the trees which characterize these forests are Hesperomeles lanuginosa, Miconia salicifolia, Monnina revoluta, Solanum bogotense, Diplostephium revolutum, Myrsine dependens and Hedyosmum huilense. Intermingled with these forests, Cuatrecasas (1954,1958) also reported within the altitudinal range of3300-3400 m forests with Weinmannia tolimensis and W hirtella, as well as forests dominated by Gynoxys spp., and Pentacalia spp. There are some notable differences regarding the physiognomy as well as the floristic composition between the forests of the re1atively dry east slope and the more humid west slope of the study area. Cleef et al. (chapter 2, this volume) and Rangel et al. (chapter 3, this volume) deal in more detail with the phytosociology of the montane forests for this part of the Central Cordillera. The third author added transect studies on montane rain forests in the deep río Otún valley just south ofthe TPN transect on the west slope ofthe Central Cordillera (Rangel 1994).

Paramo dwarf forests Cleef (1981) described dwarf and scrub forests of Aragoa abietina, Diplostephium revolutum, Hypericum spp., Pentacalia andicola, P. nitida, P. vernicosa, and many others, in the paramos of the Colombian Eastern Cordillera. Monasterio (1980) described paramo "forests" composed of Libanothamnus neriifolia, Aragoa cupressina and Alnus acuminata, in Venezuela. Valencia & Jorgensen (1992) studied the composition and structure of humid montane forests with Miconia theaezans, M. pustulata and Piper andreanum close to Quito, Ecuador. In the Parque Los Nevados area rather open and scrubby paramo dwarf forests with Gynoxys tolimensis and other Gynoxys spp., Polylepis sericea and Escallonia myrtilloides form an azonal graup separated fram the high Andean forests since they clearly occur 'extrazonally' within the paramo belt. There they form mosaics with the lower bunchgrass paramo vegetation Those are mostly found along streams and in places where the water table is near the surface between 3600 m and 3900 m. Small patches of Polylepis forests are found in sheltered place s as high as 4300 m, mainly on scree slopes associated with the steep walls of the lava escarpments. Compared to the uppermost contiguous high Andean forests extrazonal paramo dwarf forests contain fewer forest species, but also contain paramo species which are less present in the forest line stands. Occasionally, small patches of dwarf forest of Diplostephium revolutum on the west slope of the Cisne V olcano and of Pentacalia vaccinioides in the Quebrada Africa valley have been observed.

Syntaxonomy

of the paramo dwarf forests

Gynoxyo-Polylepidetum

sericeae Salamanca, Cleef & Rangel 1992

Gynoxys-Polylepis serieea dwarfforest Bosque enano altoandino eon Gynoxys y Polylepis serieea

Type relevé AMC 623. Table 2; Vol. 1, Photo 28, 29; this volume Photo 1,2,3

La vegetación de páramo

Photo 1. Interior of the open dwarf forest of Polylepis sericea (Gynoxyo-Polylepidetum sericeae) at 4300 m on the western side of the Alto La Línea (Province Risaralda). In the understorey is a low shrub of Pentacalia vernicosa. This is associated with species of Diplostephium and Gynoxys. Ground rosettes of Valeriana plantaginea are predominant together with bunchgrass. Small moss cushions of Chorisodontium mittenii are conspicuous on the trunks (relevé Cleef et al. 623, type locality for this association). - Interior del bosque abierto de Polylepis sericea (Polylepidetum sericeae) a 4300 m en el lado occidental del Alto La Línea (Dpto. Risaralda). En el sotobosque hay arbustos de Pentacalia vernicosa asociados con especies de Diplostephium y Gynoxys. Predominan las rosetas acaules de Valeriana plantaginea junto con macoJlas de gramíneas. Las almohadillas de Chorisodontium mittenii son visibles sobre los troncos de Polylepis (Iev. Cleef et al. 623, localidad tipo de la asociación).

Physiognomy: These dwarfforests are the most common ones in the paramos ofthe Ruiz-Tolima massif. They consist of; tree 1ayer, about 5-10 m high, covering from 30% to 100%, shrub 1ayer, 1-2 m high, either rather sparse (8%) or re1ative1y dense (20%), herb 1ayer, c. 50 cm high, covering from 2% to 75%, ground 1ayer covering from 2% to 95%, with redominance ofbryophytes anci/or lichens. Composition and syntaxonomy: C1eef et al. (1983) provided a short description of Polylepis serie ea forests ofthe Ruiz- Tolima massif. The Gynoxyo-Polylepidetum serieeae is re1ative1y poor in vascu1ar p1ants. The tree 1ayer consists of Polylepis serieea and Gynoxys sp., the 1atter - probab1y G. tolimensis - is rare1y present.

The paramo vegetation

Photo 2. Canopy aspect ofthe Polylepis serieea dwarfforest (Gynoxyo-Polylepidetum serieeae) ofphoto 1. Dead trunks of Polylepis serie ea are still covered by epiphytes, such as Chorisodontium mittenii (Musci) and Parmeliaceae (Lichens). - Aspecto de las copas del bosque de Polylepis serieea (Gynoxyo-Polylepidetum serieeae) de la foto 1. Además se observaron troncos muertos de Polylepis serieea todavia con epífitas de Chorisodontium mittenii (musgos) y Parmeliaceae (líquenes).

Polylepis sericea is a rosaceous tree, belonging to the section Sanguisorbeae. More than 15 species have been reported (Simpson 1979). The genus is endemic ofthe tropical Andes, occurring from the northern part of Argentina to Venezuela. Although in Colombia there are two species, in the Ruiz-Tolima massif only Polylepis sericea dwarf forests have been found. According to Simpson (l.c.), Polylepis sericea occurs from the Mérida Andes of Venezuela in the north, to the Titicaca Lake (Bolivia) in the south. The presence of Gynoxys div. spp., within Polylepis forests is well known (Cleef 1981; Arnal 1983) from the Eastern Cordillera (Colombia) and the Sierra Nevada de Mérida (Venezuela). Species in common between the Polylepis forests of the Colombian Central and the Eastern Cordilleras are Calamagrostis recta, Festuca sublimis, Pentacalia vernicosa and of the mosses are: Campylopus spp., and Pleurozium schreberi, all occurring in the ground layer. 1t is not c1ear yet if the Venezuelan Gynoxys-Polylepis sericea forests also belong to the Gynoxyo-Polylepidetum sericeae. Ecology and distribution: Dwarfforests belonging to the Gynoxyo-Polylepidetum sericeae occur in the study area between 4000 and 4200 m. These forests are found on damp soil, along paramo ravines or in sheltered places among boulders on scree slopes. Azocar & Monasterio (1979) studied the mesoc1imate in Polylepis sericea forest in the Mucubají pararno in the Venezuelan Andes. They noted the large amplitude of thermic and hydric conditions characteristic of the habitats of Polylepis sericea forests, present throughout the paramo belt in Venezuela from 3600 to 4300 m (ArnaI1983). Walter & Medina (1969) discussed the presence of Polylepis sericea forests in scree slopes in the Venezuelan Andes.

La vegetación de páramo

Photo 3. Detail of stem of Polylepis sericea with epiphytic Chorisodontium

mittenii (Musci) of photo 1.

- Detalle del tronco de Polylepis sericea con musgos epífitos de Chorisodontium foto grafía 1.

mittenii del sitio de la

Cleef (1981) summarized phytosociological traits of Polylepis quadrijuga forests, occurring between 3735 and 4025 m in the Guantiva, La Rusia and El Cocuy paramos fram the Colombian Eastern Cordillera. In the Paramo de Chingaza Velez et al. (1998) studied the high productivity of a stand of these rasaceous dwarf forests.

Dwarfforests

of Gynoxys sp. (G. tolimensis?)

Bosque enano altoandino

de Gynoxys (G. tolimensis?)

Table 2 Composition and syntaxonomy: These dwarf forests are relatively rich in species. The tree layer is dominated by 2-5 m tall Gynoxys sp. (G. tolimensis ?). Saracha (syn.Acnistus) quitensis andHypericum laricifolium occur often. Diagnostic species include Carex jamesonii, Calceolaria pentlandii, Cortaderia sericantha and Gynoxys tolimensis, Ribes sp., Valeriana pavonii, Myrrhidendron glaucescens is associated.

The parama vegetatian

These Gynoxys dwarfforests also have Myrrhidendron glaucescens, Hypericum forests dominated by Gynoxys div. spp. R. Jaramillo M. (unpubl.) in the Eastern

a number af species, e.g. Saracha (Acnistus) quitensis, laricifolium and Ribes sp., in common with the dwarf studied by Cleef (1981) and T. van der Hammen and Cordillera of Colombia.

Ecology and distribution: The Gynoxys tolimensis dwarf forests are mostly found in sheltered rock outcrops (covering a surface up to 20 m2) at high altitude. The relevés which confonn the basis for this description were made between 3960 and 4200 ID in the Ruiz-Tolima study area. The highest record is from 4400 m. Gynoxys sp. (G. tolimensis?) has been reported down to 3000 m in the Cordillera Central of Colombia in the Natural reserves of Puracé and Los Nevados.

Aciachne acicularis-Escallonia

myrtilloides dwarf forests

Bosque enano de Escallonia myrtilloides con Aciachne acicularis

Table 2; Figs.

2; Photo 4

TPN 1 3975 m

Fig. 1. Physiognomy and structure of Aciachne acicularis-Escallonia myrtilloides dwarf forest (TPN 1, 3975 m) with strong evidence of grazing and sheltering by cattle. Moraine west ofLaguna OtÚn, Risaralda province. See Photo 4. - Fisionomía y estructura del bosque enano de Aciachne acicularis-Escallonia myrtilloides (TPN 1, 3975 m) con evidencia fuerte de pastoreo y pisoteo de ganado. Morrena al oeste de la Laguna Otún, Dpto. de Risaralda. Véase Foto 4.

La vegetación de páramo

TPN7 3930 m

1 m

Fig. 2. Physiognomy and structure of Aciachne acicularis-Escallonia myrtilloides dwarf forest with columnar Espeletia hartwegiana (relevé TPN 7, 3930 m) in the grass paramo on the soutwest edge ofLaguna Otún, Risaralda province. - Fisionomía y estructura de matorral bajo de Aciachne acicularis-Escallonia myrtilloides con frailejones altos de Espeletia hartwegiana (lev. TPN 7, 3930 m) en el páramo propiamente dicho en la márgen suroccidente de la Laguna Otún, Dpto. de Risaralda.

Physiognomy: The description of these forests is based on two relevé s (TPN 1 and TPN 7). The tree layer attains a cover of only 60% and 75%, and is exdusively composed of Escallonia myrtilloides. Calamagrostis recta constitutes the tussock layer, with a cover of 10%. In the low, and open, herb layer, light demanding Aciachne acicularis has a cover ofbetween 4 % and 12%. The cover of terrestric bryophytes is c. 30%. In TPN 7 Espeletia hartwegiana is present with a cover of 25 %. The presence of Aciachne acicularis seems related with grazing. Composition: The vegetation sample has been based only on two relevés near the Laguna de Otún, and therefor this vegetation type has not been ranked according to the Ziirich-Montpellier approach. Differential is the cover of Geranium sibbaldioides and Aciachne acicularis. Characteristic taxa are also Gentianella dasyantha, Hypericum lancioides, Lachemilla holosericea and Stellaria cuspidata, among others. The influence on the vegetation of grazing is strongly induced by Aciachne acicularis, Agrostis haenkeana, Baccharis genistelloides, Eryngium humile, Lachemilla orbic~tlata, Rumex acetosella and Veronica serpyllifolia (Verweij & Budde 1992). Laegaard (1987) studied Aciachne in the tropical Andes and described most Colombian records under Aciachne acicularis Laegaard. In the past, Colombian Aciachne was referred to as A. pulvinata Bentham.

The paramo vegetation

Photo 4. Remnants of an Aciachne acicularis-Escallonia myrtilloides dwarf forest at 3975 m on the western edge ofthe Otún lake (Risaralda province). Heavy grazing in the past has resulted in the open herb layer today comprised of Agrostis cf. haenkeana (relevé TPN I and relevé Cleef & Salamanca 578). See Fig. l. - Remanentes de un bosque enano paramuno de Aciachne acicularis-Escallonia myrtilloides a 3975 msnm cerca de la orilla W de la Laguna de Otún (Dpto. de Risaralda). Como consecuencia de la influencia del pastoreo en el pasado el estrato ralo de hierbas está conformado por Agrostis cf. haenkeana (lev. TPN I and lev. Cleef & Salamanca 578). Véase Fig. 1.

Ecology and distribution: The ecology of this type of forest is not well understood yet. Escallonia scrub and dwarf forest patches have developed on old block lava flows as well as on morainic terrain near Lake atún. Locally, Escallonia myrtilloides is associated with dense stands of stem rasettes of Espeletia hartwegiana. The aspect and composition of the ground ¡ayer, especially on top of the lateral moraine, has been changed by animal grazing and droppings. AIso, fuel wood gathering took place causing an impact on Escallonia treelets. These stunted Escallonia forests were sampled at 3910 and 3930 m in the vicinity ofLake atún (see Photo 148). Escallonia myrtilloides dwarf forests have also been reported in the surroundings of Popayán (Restrepo & Duque 1992) and fram the Cordillera Oriental of Colombia (Cleef 1981).

Baccharido tricuneatae ~ Hypericetum laricifolii Salamanca, Cleef & Rangel 1992 Baccharis tricuneata - Hypericum laricifolium shrub Matorral de Hypericum laricifolium con Baccharis tricuneata

Type: relevé AMC 635. Table 2 Physiognomy: Three layers compose the structure of these tall scrub stands; scrub layer 2-3 m high, with a canopy cover fram 5% to 55%, medium high to high herb layer, mainly of bunchgrasses (covering fram 3 % to 30%), dense graund layer, consisting mostIy ofbryophytes (covering fram 10% to 45%).

La vegetación de páramo

In some forests a low herb layer is rather conspicuous, reaching covers around 25 %. Ihis community is in fact an azonal paramo scrub association for the sake of convenience and tloristic similarity included in the paramo dwarf forest table. Composition and syntaxonomy: For the Colombian Eastem Cordillera, Cleef (1981) described the Hypericetum laricifolii as a new association that included Hypericum laricifolium fa. laricoides as the dominant diagnostic species. In the association described here fa. typicum of Hypericum laricifolium is dominant (Robson 1987). Cerastium subspicatum, Geranium sibbaldioides, and Pernettya prostrata are character species in cOllllllon with the Hypericetum larici{olii ofthe Eastern Cordillera and the shrub of Baccharido tricuneatae-Hypericetum laricifolii. Baccharis tricuneata, Conyza uliginosa, Lupinus humifÚsus andMuehlenbeckia vulcanica are diagnostic for Baccharido tricuneatae-Hypericetum laricifolii of the Central Cordillera. Ecology and distribution: According to Robson (J 987) Hypericum laricifolium is present from central Peru to Venezuela. In the Colombian Andes, the distribution range is rather wide; Cleef (1981) reports Hypericum laricifolium communities occuring as low as 3580 m; other species of Hypericum occurred as low as 2500 m. Hypericum laricifolium thickets occur from the low to the high paramo proper. Ihey are found in the altitudinal range of 3835 to 4200 m in the study area along paramo streams, on the edges of bogs, along erosion gullies. Moreover, Hypericum laricifolium is already present in the high Andean belt as a component of the Hesperomeles lanuginosa forests and it is also frequently found near Plantago rigida and Distichia muscoides bogs near the lower superparamo border. According to our observations (e.g. in the Quebrada Africa valley and near Laguna El Mosquito), stands of Baccharido-Hypericetum laricifolii develop frequently as a kind of secondary scrub after destruction by tire or cutting of patches of high Andean (Gynoxys) forest.

The paramo proper Ihe physiognomy of the zonal paramo proper vegetation is mainly determined by the presence of bunches, or tussocks, of Calamagrostis recta and C. effusa. Calamagrostis intermedia may also occur, intermingled with the tussocks of C. effusa, as is the case in the Puracé area (Restrepo & Duque 1992). Other Poaceae such as Agrostis haenkeana, Bromus lanatus, Festuca dolichophylla and F. sublimis are found mainly in the more or les s azonal bunchgrasslands ofthe paramo proper, and the latter in heavily grazed and burned paramos. Chusquea tessellata (synonym: Swallenochloa tessellata, Clark 1989), an important component ofthe humid paramo vegetation in the Colombian Eastern Cordillera (Cleef 1981), seems absent from the Ruiz- Tolima massif. However, this bamboo species has been reported from the Nevado del Huila paramos in the Central Cordillera (Rangel et al. 1985) and also from the Puracé area (Duque & Rangel 1989; Restrepo & Duque 1992). Scattered scrubs of Baccharis macrantha, Diplostephium eriophorum, D. schultzii, Hypericum laricifolium, H. lancioides andPentacalia vernicosa are common among the tussocks ofPoaceae. In relatively open places, many small rosettes and prostrate shrubs shape the ground layer. Ihe acaulescent, or ground rosettes, of Eryngium humile, Gnaphalium antennarioides, Hieracium avilae, Hypochoeris sessiliflora, Oreomyrrhis andicola Oritrophium peruvianum and Senecio repens frequently occur. Baccharis caespitosa, Disterigma empetrifolium, Pernettya prostrata and Vaccinium floribundum are good examples of prostrate paramo dwarf shrubs. Extensive areas ofbogs, mainly consisting of vascular cushion plants like Plantago rigida, Distichia muscoides, Werneria

The paramo vegetation

crassa and W humilis are an important component of the landscape around 4000 m. Scattered patches of scrubs, mainly associated with slope debris, are composed of Diplostephium schultzii, D. violaceum, Hypericum lancioides. and Pentacalia vernicosa. Although they never form a continuous belt, they occur more frequendy towards the transition to the superparamo. In places with a very high grazing pressure and burning, the bunchgrassparamo is replaced by meadows or pastures (this subject is further discussed by Verweij & Budde 1992; see also Hofstede 1995 and Verweij 1995; for Ecuador by Ramsay & Oxley 1996). In this chapter, those meadows of Aciachne acicularis, Lachemilla orbiculata and Muhlenbergia cleefii will also be described. In large extensions of paramo bunchgrasslands, around the Otún lake, Calamagrostis bunches have been replaced by loose tufts of Agrostis haenkeana (Verweij & Budde 1992). In contrast with the Colombian paramos, the occurrence of bunchgrass paramos seems to be rather limited in Venezuela. Monasterio (1980) reports extensive areas exclusively dominated by the stemrosettes of Espeletia spp., but without the tussocks ofPoaceae. From the Venezuelan paramos, Poaceae are represented by Calamagrostis pittieri, Chusquea spencei, Stipa sp., Danthonia secundiflora, Poa sp., and Festuca fragilis have been documented (Berg 1998). Berg recendy reported rather different upper grassparamo communities in the high Cordillera of Mérida. These communities are dominated by Calamagr:ostis cf. heterophylla, C. pittieri, C. cf. planifolia, and Festuca tolucensis. In Ecuador, as well as in the northern part ofPeru, the bunchgrassparamos have a wide extension. Acosta-Solís (1984) lists Calamagrostis bogotensis, C. ejjitsa, C. heterophylla, C. humboldtiana, C. ligulata, C. macrophylla, C. planifolia, C. recta, C. rigida, Festuca andicola, F. do lichophylla, F. sublimis and Stipa ichu as the most common Poaceae from the Ecuadorian paramos. In the Cordillera of Talamanca, Costa Rica, Chaverri & Cleef (1996) have recorded patches ofbunchgrasslands of Stipa hans-meyeri and Festuca dolichophylla in a matrix of Chusquea (Swallenochloa) subtessellata bamboo-paramo. Calamagrostis ntermedia, C. pittieri and Agrostis tolucensis also commonly occur there. In Ecuador, Ramsay (1992) provided an overview of bunchgrass paramos using stratified sampling tecnique that covers the Ecuadorian Andes.

Zonal bunchgrassparamo Calamagrostis recta and C. effusa, either single or mixed, form the larger part of the zonal bunchgrassparamo. The environmental parameters responsible for the spatial distribution of those two different species of Poaceae are not yet well known. Calamagrostis recta seems to prefer deep sandy soils, and occurs optimally under drier and colder conditions, especially in the volcanic cordilleras of Colombia and Ecuador. Calamagrostis effusa in Colombia shows the tendency to dominate the low and middle, more humid, bunchgrassparamos; whi1e in Venezuela, this species also occurs in the more dry paramos (Monasterio 1980). On the other hand, in the Co1ombian Eastern Cordillera, Calamagrostis effusa is the most common bunchgrass. Espeletia hartwegiana ssp. centroandina is often present in paramo bunchgrass1ands. In the study area, the present extension of this stemrosette species is strongly influenced by human activities. Although little is known about the ecology of Espeletia hartwegiana in the Colombian Central Cordillera, at 1east during its early stages of growing, it seems to be quite sensitive to repetitive practices ofburning and grazing (Kloosterman et al., this vo1ume; Verweij & Kok 1992).

Syntaxonomy

of the bunchgrasslands

Cuatrecasas (1934) presented a first synsystematic ordering ofthe bunchgrassparamo vegetation in the Central Cordillera. He defined the "Espeletietum hartwegianae Calamagrostiosum" and

La vegetación de páramo

the "Espeletietum hartwegianae-Hypericetum laricifoli" on the Iolima Volcano, as "associations" including all the Calamagrostis recta-e. effitsa bunchgrassparamos. In fact Cuatrecasas' associations share some species with the associations defined in this study. According to Cleef & Rangel (1984), most ofthe north Andean bunchgrass paramos be long to the class provisionally defined as Espeletio-Calamagrostietea. Ihis c]assification of the bunchgrass paramo is introduced here again, but is now based on many more re]evés than in the case ofthe Sierra Nevada de Santa Marta. It is envisaged for the near future, that we can present a more definitive classification of all the zonal paramos of the northem Andes. Here we will provide the forma] description of the phytosocio]ogica] alliance, the order and the class of the bunchgrass paramos valid not only for the Parque Los Nevados, but also for the Central Cordillera and for the northem Andes.

Espeletio-Calamagrostietea recto-effitsae C]eef, Range] & Salamanca cl. nov. Class of paramo bunch grassland of Espeletia-Calamagrostis recta/C. effusa Clase de pajonal de páramo de Espeletia-Calamagrostis recta/e. effusa Iype: Calamagrostietalia recto-effusae (this study). Physiognomy: Equatorial open zona] paramo bunchgrass vegetation (varying in height from (10-)20 cm up to ]00 cm) with 01' without the presence of stemrosettes. Composition and syntaxonomy: Diagnostic bunchgrass species include: Calamagrostis recta, e. effusa, e. bogotensis (tuft) and Festuca sublimis. Stemrosettes: Espeletia spp., but also other members ofthe Espeletiinae (Heliantheae, Compositae). Also diagnostic are species of Altensteinia, Baccharis tricuneata, Bartsia, Castelleja, Halenia, Lachemilla, and Geranium sibbaldioides, Gnaphalium antennarioides, Grammitis moniliformis, Hypochoeris sessiliflora, Luzula racemosa, Oritrophium peruvianum, Pernettya prostrata, among others. The core flora is tropica]-Andean with temperate influences Cleef 1979; Van del' Hammen & C]eef 1986; Chaverri & Cleef 1996.). Bunchgrass species Iike Festuca dolichophylla (Mexico to Argentina), Calamagrostis macrophylla (Puracé to Central Peru), and e. intermedia (Costa Rica to Bo]ivia) are a1so diagnostico However to a lesser extent since they also occur elsewhere in the tropical American mountains. In the Parque Los Nevados study area, the order Calamagrostietalia recto-effusae (ord. nov, this study) is included. Gn a later occasion we hope to be able to define the syntaxonomic classification for paramo bunchgrasslands e]sewhere in the Colombian Andes. Dwarf bamboo paramo vegetation dominated by Chusquea tessellata (northem Andes) and Chusquea subtessellata (Centra] America) may also be included in this c]ass. It is supposed that the bamboo paramos belong to a separate order Espeletio-Chusqueetalia subtessellato-tessellatae (prov.). Synecology and distribution: Ihe mesic to dry bunch- 01' tussock grasslands are present at high altitudes in the northem Andes (Ecuador, Colombia, Venezuela) and apparently a]so in mountains in Panama and Costa Rica on sloping as well as on ]evel dry to humid ground with shallow to deep soi]s with a considerable content of blackish humic material. Daily temperatures fluctuate considerably according to the diuroal climate type defined earlier by Iroll (1968): low temperatures during the night, higher temperatures during daytime. Annual precipitation may vary between about 800 mm and more than 3000 mm.

The paramo vegetation

Calamagrostietalia recto-effusae Cleef, Salamanca & Range] ord. nov. Order of paramo bunch grassland of Calamagrostis recta/e. effusa Orden del pajonal de paramo de Calamagrostis recta/e. effusa Type: Cerastio-Calamagrostion rectae Salamanca, Cleef & Range] 1992 Physiognomy: Open zona] coarse and tall bunchgrass vegetation with or without stemrosettes. Between the bunches or tussocks, a number of herbs (scapose and prostrate species, ground rosettes) are present. Composition and syntaxonomy: The bunchgrass paramos on volcanic substrates studied in the Parque Los Nevados are examples of the vegetation inc]uded in this order. It is supposed that this type of paramo bunchgrass vegetation is present in the Central Cordillera ofColombia, the high vo]canoes in southern Colombia (Macizo Colombiano, Nudo de los Pastos), towards Central Ecuador (Ramsay 1992) and perhaps a]so in the Cordillera de MĂŠrida, Venezuela. In the Parque Los Nevados study are a, the alliances of Cerastio-Calamagrostion rectae (all. nov., this study) and Festuco-Calamagrostion ejjitsae (all. nov., this study) are included in this order. Diagnostic are: Calamagrostis recta, C. eIJitsa, C. intermedia, Espeletia hartwegiana, E. pycnophylla, Festuca dolichophylla, F. sublimis. Also diagnostic taxa are Baccharis caespitosa, Lachemilla pitosa, Bromus lanatus, Gentianella dasyantha, Lupinus microphyllus, and Satureja nubigena. This order is different from the bunchgrasslands on soils relative]y poor in nutrients on sedimentary rocks, Calamagrostietalia ejjitsae order nov. prov., a]ready referred to by C]eef & Rangel (1984) for the bunchgrass paramos of the Colombian Cordillera Oriental and the Sierra Nevada de Santa Marta. Synecology and distribution: Paramo proper bunchgrasslands are generally found on deep, relatively nutrient rich, blackish volcanic soils, located on volcanoes in the northern Andes (Central Ecuador to Central Colombia). These are situated above the upper forest line (at c. 3600-3800 m) and the ]ower limit of the superparamo (at C. 4200--4300 m). The Parque Los Nevados bunchgrass paramos are therefor considered as a type locality.

Cerastio subspicati-Calamagrostion rectae Cleef, Salamanca & Range], all. nov. Alliance of paramo bunch grassland of Calamagrostis recta with Cerastium subspicatum Alianza de pajonal del pĂĄramo de Calamagrostis recta con Cerastium spicatum Type: Calandrinio acaulis-Calamagrostietum rectae Sa]amanca, Cleef & Rangel 1992 Physiognomy: Open zonal bunchgrassland most]y with Espeletia stemrosettes. The ground cover between the big tussocks, or bunches, consists of a number of low herbs and bryophytes. They are affected by dai]y frost heaving in the uppermost reaches of the bunchgrass zone. Composition and syntaxonomy: Character species include Aphanactis jamesoniana, Calamagrostis recta, Cerastium subspicatum, Colobanthus quitensis, Erigeron chionophilus, Lachemilla holosericea, Senecio formosus andValeriana plantaginea. In the Parque Los Nevados study area, paramo bunchgrassland of Calandrinio-Calamagrostietum rectae and Calamagrostietum effuso-rectae are included in the alliance here described. The assemblage of the diagnostic species referred to here is differentiated against the bunchgrass paramo of Festuco-Calamagrostion effusae downslope. Upslope, the superparamo blue grasslands (Festuco breviaristatae-Agrostion araucanae) are found.

La vegetación de páramo

Synecology and distribution: Most of these zonal bunchgrasslands are present on deep vo1canic soils. These are subjected to daily frast heaving. This affects particularly the uppermost bunchgrass communities. In the study area ofthe Parque Los Nevados bunchgrass vegetation ofthis alliance is present between about 4000 and 4400 m al1.

Calandrinio acaulis-Calamagrostietum rectae Salamanca, Cleef & Rangel1992 Paramo bunchgrassland of Calamagrostis recta with Calandrinia acaulis Pajonal del páramo de Calamagrostis recta con Calandrinia acaulis Type: relevé TPN 5. Table 3; Figs. 3-8; Photo 5-9; (see aIso vol. 1, Photo 12, 17; Fig. 20) Physiognomy: The Calamagrostis recta bunchgrass vegetation, which can be highly variable in cover, encompasses those bunchgrasslands reaching fram the upper part of the paramo proper to the lower ¡imit of the superparamo. Three layers can be distinguished; - high tussock (bunchgrass) layer up to 1 m, almost exclusively composed of Calamagrostis recta, - low herb layer, - ground layer with rosette herbs and a high cover of terrestric mosses, In the variant of Espeletia hartwegiana a low stemrosettes of Espeletia (up to c. 1 m) are always presen1. in the bunchgrass layer. Composition and syntaxonomy: The almost exclusive contribution of Calamagrostis recta to the bunchgrass layer is the main criterion for the definition ofthis association. Agrostis breviculmis, Calandrinia acaulis, Draba lindenii and Montia meridensis are diagnostic taxa. The differences in the floristic composition

TPN

4550 m

Fig.3. Zonal upper bunch grass páramo of Calandrinio-Calamagrostietum rectae variant typicum at 4550 m on the east slope ofthe summit ofvolcano Santa Rosa (relevé TPN 8), Risaralda province. - Pajonal zonal del páramo propiamente dicho alto del Calandrinio-Calamagrostietum recta e variante typicum a 4550 m en el lado este del cumbre del Volcán de Santa Rosa (lev. TPN 8), Dpto. de Risaralda.

The paramo vegetation

TPN9 4330 m

Fig.4. Zonal upper bunch grass páramo of Calandrinio-Calamagrostietum rectae variant typicum at 4330 m in the Paramo of Santa Rosa, east ofthe Valle San Ramón between OtÚn and Hacienda La Sierra (relevé TPN 9), Risaralda province. See Photo 5. - Pajonal zonal del páramo propiamente dicho alto del Calandrinio-Calamagrostietum rectae variante typicum a 4330 m en el Páramo de Santa Rosa, al este del Valle de San Ramón en el camino de OtÚn a la Hacienda La Sierra (lev. TPN 9), Dpto. de Risaralda. Véase Foto 5. TPN 4 4350 m

Fig. 5. Zonal upper bunch grass páramo of Calandrinio-Calamagrostietum hartwegiana ssp. centroandina Risaralda province.

at 4350 m on the northwest slope ofNevado

rectae variant of Espeletia Santa Isabel (relevé TPN 4),

- Pajonal zonal del páramo propiamente dicho alto del Calandrinio-Calamagrostietum rectae variante de Espeletia hartwegiana ssp. centroandina a 4350 m en la vertiente norte-occidental del Nevado de Santa Isabel (lev. TPN 4), Dpto. de Risaralda.

La vegetación de páramo

TPN 30 4315m

1 m

Fig. 6. Zonal upper bunch grass páramo of Calandrinio-Calamagrostietum rectae variant of Espeletia hartwegiana ssp. centroandina at 43 l 5 m south ofthe pass and southeast of the Nevado Santa Isabel in the headwaters ofQuebrada Africa (relevé TPN 30), Tolima province. See Photo 9. - Pajonal zonal del páramo propiamente dicho alto del Calandrinio-Calamagrostietum rectae variante de Espeletia hartwegiana ssp. centroandina a 4315 m al sur del Paso y al sureste del Nevado de Santa Isabel en las cabeceras de la Quebrada Africa (lev. TPN 30), Dpto. del Tolima. Véase Foto 9. TPN6 4150 m

Fig. 7. Zonal upper bunch grass páramo of Calandrinio-Calamagrostietum rectae variant of Espeletia hartwegiana ssp. centroandina at 4150 m between the Laguna Otún and the soutwest slope ofNevado Santa Isabel (relevé TPN 6), Risaralda province. See Photo 6. - Pajonal zonal del páramo propiamente dicho alto del Calandrinio-Calamagrostietum rectae variante de Espeletia hartwegiana ssp. centroandina a 4150 m en el camino de Otún al Nevado de Santa Isabel (lev. TPN 6), Dpto. de Risaralda. Véase Foto 6.

The paramo vegetation

TPN 32 4125 m

Fig. 8. Zonal upper bunch grass páramo of Calandrinio-Calamagrostietum

rectae variant of Espeletia hartwegiana ssp. centroandina at 4125 m at the southern side of Quebrada Africa in the headwaters ofValle del Totarito (relevé TPN 32), Tolima province. See Photo 7.

- Pajonal zonal del páramo propiamente dicho alto del Calandrinio-Calamagrostietum rectae variante de Espeletia hartwegiana ssp. centroandina a 4125 m en la márgen derecha de la Quebrada Africa en las cabeceras del Valle del Totarito (lev. TPN 32), Dpto. del Tolima. Véase Foto 7.

Photo 5. Open bunchgrass páramo ofthe variant typicum (relevé TPN 9) of Calandrinio acaulis-Calamagrostietum rectae close to its upper Iimit at 4330 m in the Páramo de Sta. Rosa, close to the Valle de San Ramón (Risaralda province). See Fig. 4. - Pajonal paramuno abierto de la variante typicum (lev. TPN 9) del Calandrinio acaulis-Calamagrostietum rectae a 4330 m en su límite altitudinal en el Páramo de Sta. Rosa, cerca del Valle de San Ramón (Dpto. de Risaralda). Véase Fig. 4.

La vegetación de páramo

Photo 6. Collecting of soil samples and plant species in relevé site TPN 6 at 4150 m in the bunchgrass páramo of the variant of Espeletia hartwegiana ssp. centroandina of Calandrinio acaulis-Calamagrostietum rectae on the southwestern slope ofNevado Sta. Isabel, about 1 km north ofthe Otún lake (Risaralda province). See Fig. 7. - Colección de muestras de suelo y de plantas dellev. TPN 6 a 4150 m en el pajonal paramuno de la variante de Espeletia hartwegiana ssp. centroandina del Calandrinio acaulis-Calamagrostietum rectae en el lado SW del Nevado de Sta. Isabel aproximadamente l km al norte de la Laguna de Otún (Dpto. de Risaralda). Véase Fig. 7.

Photo 7. Relevé TPN 32 at 4125 m in the Totarito Valley, left side ofQuebrada Africa, northeast ofthe pass (Tolima province). Semi-open páramo bunchgrassland of the variant of Espeletia hartwegiana ssp. centroandina de Calandrinio acaulis-Calamagrostietum rectae. See Fig. 8. - Levantamiento TPN 32 a 4125 m en el Valle de Totarito, márgen derecha de la Quebrada Africa, al norte oriente del paso (Dpto. del Tolima). Pajonal paramuno semiabierto de la variante de Espeletia hartwegiana ssp. centroandina de Calandrinio acaulis-Calamagrostietum rectae. Véase Fig. 8.

The paramo vegetation

Photo 8. Flowering Senecio isabelis at 4300 m in the upper grass páramo (Calandrinio acaulis-Calamagrostietum rectae val'. of Espeletia hartwegiana ssp. centroandina) east ofthe Laguna de OtÚn (Risaralda province). - Senecio isabelis florecido en el pajonal del páramo propiamente dicho alto (Calandrinio acaulis-Calamagrostietum rectae var. de Espeletia hartwegiana ssp. centroandina) a 4300 msnm al oriente de la Laguna de OtÚn (Dpto.de Risaralda).

Photo 9. southeast troandina influence

Relevé TPN 30 at 4315 m in the headwaters of the Valle Quebrada Africa, south of the pass and ofNevado de Santa Isabel. Páramo bunchgrassland ofthe variant Espeletia hartwegiana ssp. cenof Calandrinio acaulis-Calamagrostietum rectae on sloping ground. Nearby are two tracks with of grazing and trampling (on more level ground). See Fig. 6.

- Levantamiento TPN 30 a 4315 m sobre un talud de derrubios al Sur del Paso (al suroriente del Nevado de Santa Isabel) en el valle alto de la Quebrada Africa (Dpto. del Tolima). Pajonal paramuno de la variante de Espeletia hartwegiana ssp. centrondina del Calandrinio acaulis-Calamagrostietum recta e en la parte inclinada. Cerca hay dos caminos de herradura con influencia de pastoreo (en la palie más plana). Véase Fig. 6.

La vegetación de páramo

of the two variants belonging to this syntaxon reflect extreme environmental bunchgrasslands near the altitudinallimit of the paramo proper.

changes in the

Syneco]ogy and distribution: This association is found on sandy deposits fomled by o]d pyroclastic flows. Most of these are currently covered by incipient soils, affected by perig]acial processes in the lower border of the superparamo. The uppermost distribution of this syntaxon coincides well with the altitudinal limit of growth of Calamagrostis recta. Frost heaving between the bunches occurs almost daily in bare soil patches. The association Calandrinio acaulis-Calamagrostietum rectae is newly described for the Ruiz-Tolima massif. It extends between 4]25 and 4350 m on the Volcano Nevado de Santa Isabel; between 4200 and 4440 m on the Vo1cano Nevado de Santa Rosa and it was found between 4140 and 4300 m on the Volcano Nevado del Cisne. In the Colombian Eastem Cordillera, the extension of Calamagrostis recta bunchgrasslands is very limited. Cleef (198]) reported bunchgrasslands, with Calamagrostis recta and Jamesonia bogotensis as a characteristic species, as high as 4500 m in the uppermost bunchgrass paramo on the dry side of the Sierra Nevada del Cocuy.

Variant typicum Salamanca, Cleef & Rangel1992 Variante typicum

Type: relevé SS 82. Table 3; Figs. 3, 4; Photo 5 Physiognomy: ]n this variant of Calamagrostis recta vegetation, the Espeletia stemrosette layer is absent. However, the herb layer is rather dense, covering as much as 45%. Composition and syntaxonomy: The absence of Espeletia hartwegiana is the differentiating criterion. Moreover, this syntaxon is relatively poor in plant species. Some species, largely restricted to the lower superparamo, like Agrostis ¡oliata, Lachemilla tanacetifolia and Thamnolia vermicularis occur in the vegetation of the variant typicum. Syneco]ogy and distribution: The soils (mainly Vitrandepts and Cryorthents) above 4200 m are poor]y developed and affected by the periglacia] conditions of the superparamo climate. This bunchgrass vegetation is transitional to the ]ower-most superparamo. Bunchgrass paramos be]onging to this variant are in the upper part of the distribution range (mainly between 4200 and 4400 m) of Calandrinio acaulisCalamagrostietum rectae.

Variant of Espeletia hartwegiana ssp. centroandina Salamanca, C]eef Variante de Espeletia

hartwegiana

& Range] 1992

ssp. centroandina

Type: relevé TPN 5. Tab]e 3; Figs. 5-8; Photo 6-9; (see also vol. 1, Fig. 20; Photo 12, 17) Physiognomy: In the vegetation of this variant the tussocks of Calamagrostis recta are intermingled with the low stemrosettes of Espeletia hartwegiana ssp. centroandina. The Espeletia ]ayer covers between ]0% and 45 %. The herb layer, covers between 4% and 20% and is somewhat more open than in the grass]and of var. typicum. A]so shrubs are more abundant than in the var. typicum. grassland.

The paramo vegetation

Composition and syntaxonomy: Differentiating from other variants is the presence of Espeletia hartwegiana ssp. ceritroandina and the overall higher species richness. Castillejajissifolia, Niphogeton dissecta, Ophioglossum crotalophoroides and Polystichum polyphyllum are absent fram the grassland of var. typicum. of Calandrinio acaulis-Calamagrostietum rectae. Synecology and distribution: Soils are more developed than under the bunchgrass vegetation of variant typicum. Compared to the bunchgrass paramo of variant typicum. slightly higher temperatures cause limited frast heaving and allows for the presence of more species. Bunchgrass paramos belonging to this variant are mainly found between 4125 and 4300 ffi. In the study area these are foundwithin the upper part of the paramo proper belt, and are contiguous below those of the bunchgrassparamo of Calandrinio acaulis-Calamagrostietum rectae var. typicum.

Calamagrostietum ejjitso-rectae Salamanca, Cleef & Rangel 1992 Paramo bunchgrassland of Calamagrostis effusa and C. recta Pajonal de páramo de Calamagrostis effusa y C. recta Type: relevé SS 2. Table 3; Fig. 9; Photo 10, 11; (see also vol. 1, Photo 15) Physiognomy: This syntaxon refers to dense bunchgrasslands, with an average cover of 50% of the tussock layer. In this five layered vegetation type, the Espeletia stemrosette layer covers from 5% to 25%; the scrub ¡ayer about 5%; the herb layer between 5% and 25%; and the ground ¡ayer

TPN 26 3900 m

Fig.9. Zonal bunch grass páramo of Calamagrostietum ejJitso-rectae at 3900 m on 'lahar' at the northem side ofQuebrada Africa in the headwaters ofValle del Totarito (relevé TPN 26), Tolima province. See Photo 11. - Pajonal zonal del páramo propiamente dicho del Calamagrostietum effitso-rectae a 3900 m sobre flujo de lodo en la márgen izquierda de la Quebrada Africa en las cabeceras del Valle del Totarito (lev. TPN 26), Dpto. del Tolima. Véase Foto 11.

La vegetación de páramo

Photo 10. Páramo bunchgrass vegetation (relevé TPN 31) of Calamagrostietum effilso-rectae with stem rosettes of Espeletia hartwegiana ssp. centroandina at 4200 m between the pass and the sources ofTotarito river in the headwaters of Quebrada Africa (Tolima province). - Pajonal paramuno (lev. TPN 31) del Calamagrostietum effitso-rectae con caulirrósulas de Espeletia hartwegiana ssp. centroandina a 4200 msnm entre el paso y el nacimiento del río Totarito en el valle alto de la Quebrada Africa (Dpto. del Tolima).

Photo 11. Stem rosette-bunchgrassland (rel. TPN 26) of Calamagrostietum ejJuso-rectae con Espeletia hartwegiana ssp. centroandina at 3900 m in the Totarito valley, left side ofthe Quebrada Africa (Tolima province). See Fig. 9. - Pajonal paramuno con caulirrósulas (lev. TPN 26) del Calamagrostietum ejJuso-rectae con Espeletia hartwegiana ssp. centroandina a 3900 m en el Valle del Totarito, márgen izquierda de la Quebrada Africa (Dpto. del Tolima). Véase Fig. 9.

from 3% to 25%. Ground cover can become rather dense in those places not shadowed by the tussocks. The cover ofthe bryophytes ranges from less than 1% to 50%. Sometimes lichens can be abundant, covering as much as 30% of the ground layer.

The paramo vegetation

Composition and syntaxonomy: Diagnostic taxa for this association are Castilleja fissifolia, Calamagrostis ejjÚsa and Espeletia hartwegiana occurring together. This association has a group of species in common with Calandrinio acaulis-Calamagrostietum rectae. Ihese include, besides Calamagrostis recta and C. efjÚsa; Aphanactis jamesoniana, Cerastium subspicatum, Luzula racemosa, Senecioformosus andValeriana plantaginea. The association Calamagrostietum ejJuso-rectae also shares some species with the two associations described by Cuatrecasas (1934) fram Tolima Volcano (see also chapter 4). Synecology and distribution: Ihe bunchgrass paramo belonging to this association thrives on non-differentiated Andosols, with an A~C profile, pH values around 6 and sometimes with high contents of aluminiul11. Ihe association Calamagrostietum ejJuso-rectae includes the bunchgrasslands of Calamagrostis recta and C. effilsa of the middle part ofthe paramo proper belt throughout the study area. It extends cOl11l11onlybetween 3900 and 4200 m.

Festuco dolichophyllae-Calamagrostion

ejJusae Cleef, Salamanca

& Rangel all. nov.

AlIiance of paramo bunchgrassland of Festuca dolichophylla and Calamagrostis effusa Alianza de pajonal del páramo de Festuca dolichophylla and Calamagrostis effusa

Type: Espeletio hartwegianae-Calamagrostietum

ejjÚsae Salamanca, Cleef & Rangel 1992

Physiognomy: Ihis syntaxon refers to dense bunchgrass paral110 vegetation with or without stemrosettes. Between the bunches species of low herbs and dwarf shrubs, bryophytes and lichens are found. Composition and syntaxonomy: Diagnostic for this syntaxon are: Calamagrostis ejJusa (highest presence and cover), Carex pichinchensis, Espeletia hartwegiana ssp. centroandina (p.p.), Festuca dolichophylla (the latter two were recorded in half of the relevés that belong to this alliance), Hieracium avilae, Lycopodium spurium and Nertera granadensis. The alliance comprises two associations; FestucoCalamagrostietum effilsae and Espeletio-Calamagrostietum ejJusae. The alliance is separated frol11 Cerastio-Calamagrostion rectae by the combined presence of diagnostic species of both associations. The alliance is separated from Cerastio-Calamagrostion rectae by the near absence of Baccharis caespitosa, Diplostephium schultzii, Erigeron chionophilus, Gentianella dasyantha, Jamesonia goudotii, Lachemilla nivalis and Pentacalia vernicosa among others. FestucoCalamagrostietum ejJusae is separated from Espeletio-Calamagrostietum effÚsae by the presence of Azorella multifida, Bromus lanatus, Calamagrostis recta, Cotula minuta, Lucilia kunthiana, Oreomyrrhis andicola and Ranunculus peruvianus. Espeletia is absent in Festuco-Calamagrostietum ejJusae, but diagnostic in Espeletio-Calamagrostietum ejJusae together with Agrostis tolucensis, Baccharis rupicola, B. genistelloides, Castilleja fissifolia and Halenia spp. Synecology and distribution: In general these grassland coml11unities are less adapted to cold. These grassland cOl11munities are strong1y affected by buming and grazing more than in any other vegetation type. Bunchgrasslands belonging to the alliance are commonly distributed between 3850 and 4250 111in the Parque Los Nevados.

La vegetación de páramo

Festuco dolichophyllae-Calamagrostietum

effusae Salamanca, Cleef

& Rangel1992

Bunchgrass paramo ofFestuca dolichophylIa and Calamagrostis effusa Pajonal de páramo de Festuca dolichophylIa and Calamagrostis efIusa

Type: relevé SS 85. Table 3; Fig. 10; Photo 12 Physiognomy: Three layers can be distinguished in this type ofbunchgrass paramo: - medium close to close tussock layer, 0.6 to 1 m high, mainly composed of Festuca dolichophylla and Calamagrostis ejjitsa, covering between 50% and 90%, - sparse herb layer, around 30 cm high, covering between 2% and 15%, - close ground layer, including rosette herbs, prostrate dwarf shrubs, bryophytes and lichens. Composition and syntaxonomy: The diagnostic species are: Calamagrostis effusa and Festuca dolichophylla. The absence of Aphanactis jamesoniana, Cerastium subspicatum, Colobanthus quitensis, Luzula racemosa, Senecio formosus andValeriana plantaginea is also diagnostico Bromus lanatus, Calamagrostis recta, Cotula minuta, Lucilia kunthiana, Oreomyrrhis andicola, Ranunculus praemorsus and Taraxacum spp. are also present within the Calandrinio acaulis-Calamagrostietum rectae. Synecology and distribution: The grassland of Festuco dolichophyllae-Calamagrostietum ejjitsae was observed in the external fringes of small glacier valleys, on moraines, or within those places that are occasionally flooded. Individual tussocks of Festuca dolichophylla frequently accompany Plantago rigida cushion bogs. Cleef et al. (1983) already reported bunchgrasslands, with Festuca dolichophylla as the dominant tussock grass, on the external slopes ofthe volcanic massifbetween 3800 and 4250 m.

TPN 14 3960 m

Fig.l0. Zonal bunch grass páramo of Festuco-Calamagrostietum effitsae at 3960 m in the valley ofQuebrada Betania, Hacienda La Sierra, Municipality of Santa Rosa de Cabal (relevé TPN 14), Risaralda province. - Pajonal zonal del páramo propiamente dicho del Festuco-Calamagrostietum e.ffitsae a 3960 m en el valle de la Quebrada Betania, Hacienda La Sierra, Municipio de Santa Rosa de Cabal (lev. TPN 14), Dpto. de Risaralda.

The paramo vegetation

Photo 12. Relevé site ofTPN 35 at 3800 m in bunchgrassland of Festuco dolichophyllae-Calamagrostietum ejJusae with stem rosettes of Espeletia hartwegiana ssp. centroandina in the Totarito valley, left side ofthe Quebrada Africa (Tolima province). - Sitio del levantamiento TPN 35 a 3800 m en el pajonal del Festuco dolichophyllae-Calamagrostietum effilsae con caulirrósulas de Espeletia hartwegiana ssp. centroandina en el Valle de Totarito, márgen izquierda de la Quebrada Africa (Dpto. del Tolima).

Festuca dolichophylla is a common element ofthe bamboo paramos in the Eastern Cordillera of Colombia e.g. Chusquea (communities with species of Sphagnum and Breutelia described by Cleef (1981). Chusquea tesselata was previously denominated Swallenochloa tesselata by this author. Acosta-Solís (1984) and J0rgensen & Ulloa Ulloa (1994) reported Festuca dolichophylla as a common species (2700--4200 m) in the Ecuadorian paramos. Chaverri & Cleef (1996) studied vegetation with Festuca dolichophylla and Chusquea subtessellata in the Costa Rican paramos between 3400 and 3600 m. They also reported Pernettya prostrata and species of Geranium, Gnaphalium and Lachemilla as companions. Festuca dolichophylla also has been recorded as a constituant of dry alpine grassland in Ecuador (J0rgensen & Ulloa Ulloa 1994), Peru (Gutte 1985) and Bolivia (Seibert & Menhofer 1992).

Espeletio hartwegianae-Calamagrostietum

ejJusae Salamanca, Cleef & Range11992

Paramo bunchgrassland of Calamagrostis effusa with Espeletia hartwegiana Pajonal de páramo de Calamagrostis effusa con Espeletia hartwegiana

Type: relevé TPN 34. Table 3; Fig. 11; (see also vol. 1, Photo 3-5) Physiognomy: These stemrosette bunchgrasslands show a distinct four layered stratification; - tussock layer, 0.6-1 m high, with a cover between 30% and 70%, - Espeletia layer, 1.5-3 m high, with the stemrosettes of Espeletia covering between 1% and 40%, - herb layer, with a height of 30 cm covering between < 1% and 20%, - ground layer, covering between 2% and 15%.

La vegetación de páramo

TPN10 4175 m

Fig.11. Zonal bunch grass páramo of Espeletio-Calamagrostietum

volcanoSanta Rosa (relevé TPN

10),

efJitsae at 4175 m on the west slope of

Risaralda province.

- Pajonalzonal del páramo propiamente dicho del Espeletio-Calamagrostietum oestedel Volcán de Santa Rosa (lev. TPN 10), Dpto. de Risaralda.

ejJusae a 4175 m en el lado

Composition and syntaxonomy: Diagnostic for this association is the absence of Aphanactis jamesoniana, Cerastium Sub5picatum, Luzula racemosa, Senecio formosus and Valeriana plantaginea. In stands with a relatively open tussock layer small acaulescent rosettes, like Eryngium humile, Senecio repens and Gnaphalium antennarioides as well as terrestric bryophytes, become more abundant and conspicuous, with cover as high as 80%. Baccharis rupicola, Castilleja fissifolia, Espeletia hartwegiana, Lysipomia muscoides and Niphogeton dissecta form a group of species shared by Calandrinio acaulis-Calamagrostietum rectae var. Espeletia hartwegiana, Calamagrostietum ejJuso-rectae and Espeletio hartwegianaeCalamagrostietum ejJusae. Synecology and distribution: The bunchgrassparamos of Espeletio hartwegianae-Calamagrostietum ejJusae are associated with humic and poorly differentiated Andosols (Thouret 1983). This association is rather com1110nin the middle part ofthe paramo proper belt in the study area (between 3920 and 4250 m). Cleef et al. (1983) ha ve already reported bunchgrasslands of Calamagrostis ejJusa and Espeletia hartwegiana ssp. centroandina from the external, humid, slopes of the Ruiz- Tolima massif. Rangel & Lozano (1986) reported Calamagrostis ejJusa-Espeletia hartwegiana communities on the Puracé Volcano between 3300-3400 m. Stunn & Rangel (1985) report Calamagrostis effusa bunchgrass paramos from the volcanoes Cumbal and Chiles. On the Nevado del Huila, according to the same authors, Calamagrostis ejJusa is not dominant nor does it forrn a typical bunchgrassparamo, though it is present in the paramo belt.

The paramo vegetation

The bunches of Calamagrostis effitsa dominate throughout the paramo proper in the Eastern Cordillera and, according to Cleef (1981), they can be found in dry paramos as well as in humid bamboo paramos together with Chusquea.

Azonal paramo vegetation Cushion bogs Geophytes and chamaephytes are the main constituents ofthe cushion-like vegetation, currently well known from the high tropical Andes. The phytosociological ranking of the cushion bog vegetation proposed by Cleef (1981) for the Colombian Eastern Cordillera seems valid for all the other paramos in Colombia within the order Oritrophio- Wernerietalia Cleef 1981 and the alliances Wernerion crassae-pygmaeae and Gentiano-Oritrophion (Cleef, l.c.). Rivas-Martinez & Tovar (1982) provided a syntaxonomical update of tropical Andean cushion bogs including the class level: Plantagini rigidae-Distichietea muscoides.

Wernerietum humilis Salamanca, Cleef & Rangel1992 Cushion bog ofWerneria humilis Turbera de cesped de Werneria humilis

Type: relevé AMC 603. Table 4; Photo 13 Physiognomy: Stands include small loose cushions, with a layer of cushion chamaephytes covering between 15% and 90%. Tussocks of Poaceae may be present with low cover percentages (1% to 15%). The bryophyte layer is well developed; achieving up to 60% of the total cover.

Photo 13. Cushion of Werneria humilis (Wernerietum humilis) situated in a Plantago rigida cushion bog (Gentianello dasyanthae-Plantaginetum rigidae) at about 4200 m on the northwestern side ofthe Nevado del Ruiz (Caldas province). Noteworthy are also some ground rosettes of Gentianella dasyantha.

- Cojín de Werneria humilis (Wernerietum humilis) ubicado en una turbera de cojines de Plantago rigida (Gentianella dasyanthae-Plantaginetum rigidae) a ca. 4200 m en el lado occidental del Nevado del Ruiz (Dpto. de Caldas). Además son notorias algunas rosetas sésiles de Gentianella dasyantha.

La vegetación de páramo

Composition and syntaxonomy: The cushion vegetation of the association Wernerietum humilis is rather poor in species diversity. Distichia muscoides and Plantago rigida are diagnostic in the variant of Distichia muscoides; Hypochoeris sessiliflora in the other variant. Carex peucophila, a diagnostic species of the alliance, is present in most of the relevés ;"ith a high total cover. Synecology and distribution: The cushions belonging to this association (occurring in the paramo praper between 4000 and 4400 m) are found on the wet and cold glacial valley floors, where often the water table reaches the surface. Werneria humilis cushions frequently occurr in Plantago rigida bogs. Isolated cushions of Wernerietum humilis are also found in very wet (micra )habitats ofthe lower superparamo outcrops. Here they are associated with the open grassland ofthe association Senecioni latifloriCalamagrostietum ligulatae. Although Werneria humilis has a wide distribution in the superparamos of the Eastem and Central Cordilleras, the true cushion vegetation of this association is not common. Rangel & Lozano (1986) also report Werneria humilis cushions from 4050 m on the Puracé Vol cano, Central Cordillera of Colombia. Cleef et al. (1983) reported Werneria humilis among the character taxa of the association Oritrophio limnophili- Wernerietum pygmaeae found on the Santa Isabel Volcano. The same species also occurs in the superparamo vegetation of the Sumapaz and the Sierra Nevada del Cocuy paramos in the Colombian Eastem Cordillera. Acosta-Solís (1984) reports Werneria humilis as an element of the paramo cushion vegetation, in Ecuador. Ramsay (1992) described in Ecuador different zonal types of what he calls cushion paramo (4100--4400 m) with Werneria humilis from the volcanoes El Altar, Cotacachi and the Páramo de Guamaní in Ecuador. Werneria humilis seems also present in Peru.

Variant of Hypochoeris sessiliflora Salamanca, Cleef Variante de Hypochoeris

& Rangel1992

sessiliflora

Type: relevé AMC 603. Table 4 Composition and syntaxonomy: Differential species of this variant are Breutelia sp., Hypochoeris cleefii and Riccardia spp.

sessiliflora, Muhlenbergia

Synecology and distribution: Small stands of the variant of Hypochoeris sessiliflora of the association Wernerietum humilis are found in the altitudinal range of 4000 m to 4400 m, mainly in small flat areas on the slopes of the Nevado del Ruiz.

Variant of Distichia muscoides Salamanca, Cleef

& Rangel1992

Variante de Distichia muscoides

Type: rel. SS 113. Table 4 Composition and syntaxonomy: Distichia muscoides is the differential species. Moreover, the floristic composition at the species level is les s diverse, and species likeAgrostis haenkeana, Azorella aretioides, Baccharis caespitosa, Bromus lanatus and Gentiana sedifolia among others, are absent fram the vegetation of bogs belonging to this variant. But present in the vegetation is the variant of Hypochoeris sessiliflora.

The paramo vegetation

Synecology and distribution: Lax cushions of the variant of Distichia muscoides of the asociation Wernerietum humilis were found at 4200 m in flat areas, on moist soil and along the slopes of Santa Isabel Volcano.

Floscaldasio hypsophilae-Distichietum muscoides Cleef 1981 Variant of Cotula minuta vaL nov. (this study) Floscaldasia hypsophila-Distichia muscoides cushion bog; Cotula minuta variant Turbera de cojines de Distichia muscoides con Floscaldasia hypsophila; Variante de Cotula minuta

Table 4; Fig. 12; (see also vol. 1, Photo 27, 30) Physiognomy: The association comprises flat to convex cushions of Distichia muscoides. The young and firm cushions are poor in companion species. However, the cover ofthe small herbs is higher on the top of mature cushions. Composition and syntaxonomy: The association Floscaldasio hypsophilae-Distichietum muscoides already has been described for the Cordillera Oriental. Cleef et al. (1983) also provided a short description ofthis vegetation type present in the study area. Besides Distichia muscoides and Floscaldasia hypsophila other character species are Bryum argenteum, Calamagrostis coarctata and Gymnocoleopsis multiflora. On decaying cushions, Calamagrostis coarctata may achieve high cover. Cotula minuta is differential for the Central Cordilleran Distichia cushion bogs. They belong to the variant of Cotula minuta. Different species have been reported within hollow communities around lake Otún at 3950 m the reddish

Fig. 12. Small cushion bog of Floscaldasio-Distichietum muscoides (relevé Cleef & Salamanca 582) at 4300 m in contact with upper bunchgrass paramo (Calandrinio-Calamagrostietum rectae) and lower superparamo sClUb of Loricarietum colombianae (relevé Cleef & Salamanca 593) on outcrops of volcanic rock on the soutwest side ofNevado Santa Isabel, Risaralda province. - Turbera de cojines del Floscaldasio-Distichietum muscoides (lev. Cleef & Salamanca 582) a 4300 m en contacto con pajonal del páramo propiamente dicho alto (Calandrinio-Calamagrostietum rectae) y matorral bajo del superpáramo bajo del Loricarietum colombianae (lev. Cleef & Salamanca 593) sobre afloramientos de roca volcánica en el lado suroccidente del Nevado de Santa Isabel, Dpto. de Risaralda.

La vegetación de páramo

coloured Calamagrostis jamesonii is particularly conspicuous. Scirpus cernuus has also been found common at 3950 m on top of the Distichia cushions in neighbouring Laguna Mosquito. Synecology and distribution: In the Ruiz-Tolima massif, Distichia muscoides cushion mire is present mainly above 4000 m in the high paramo proper and in the superparamo. Distichia muscoides forms soligenous cushions in concave terrains with a peaty substrate, especialIy in the depressions left by former glacial lakes. Rangel & Lozano (1986) observed Distichia muscoides cushions at 3950 m on the Puracé Volcano. Duque & Rangel (1989) studied the same cushion type vegetation, which they ranked as Agrostio boyacensis-Distichietum muscoides. In Ecuador Ramsay (1992) reported a Distichia muscoides-Azorella corymbosa- Werneria humidis cushion paramo at 4100 m on the El Altar Volcano, Ecuador. In addition to Gutte (1980) with the association Stylito andicolae-Distichietum muscoides, Rivas-Martínez & Tovar (1982) described the Calamagrostio jamesonii-Distichietum muscoides fram Central Peru. Seibert & Menhofer (1992) studied a "Scirpo deserticolae-Distichietum muscoides" from the Bolivian Andes. Ruthsatz (1977; 1995) studiedDistichia muscoides cushion bogs fram the Andes ofnorthern Argentina and northern Chile.

Carici peucophilae- Wernerietum crassae Cleef 1981 var. Cotula mexicana Salamanca, Cleef & Rangel 1992 Werneria crassa cushions with Carex cC.peucophila; Cotula mexicana variant Turbera de cesped de Werneria crassa con Carex cf. peucophila; Variante de Cotula mexicana Type: rel. SS 152. Table 4 Physiognomy: The vegetation of this association, defined by Cleef (198 1) for the paramos of the Colombian Cordillera Oriental, comprises loose cushions of Werneria crassa. These cover between 40% and 80 % and are associated with a well-developed bryophyte layer, up to coverages of 25%. Sometimes tussocks of Poaceae can be found fram 5% to 50%. In some of the relevés, dwarf shrubs achieve a cover fram 2% to 60%. Composition and syntaxonomy: Diagnostic species of this Central Cordilleran association are Cotula mexicana, Breutelia sp., Cladina cf. rangiferina, Muhlenbergia cleefii, Plagiocheilus solivaeformis and Riccardia sp(p.). Cleef (1981) defined Carici peucophilae-Wernerietum crassae (with subass.wernerietosum crassae) as a new syntaxon for the Eastern Cordillera. From this syntaxon Bartsia sp., Breutelia sp., Muhlenbergia cleefii, Hypericum lancioides, Oritrophium limnophilum, Plantago rigida and Riccardia spp., among others, also occur in the variant described here. Differential for the Central Cordillera are Bromus lanatus, Cotula mexicana, Gentianella dasyantha and Werneria crassa ssp. crassa (versus Werneria crassa ssp. orientalis). Synecology and distribution: In the Ruiz- Tolima volcanic massif, the vegetation belonging to Carici- Wernerietum crassae is found mainly on flat glacial valley bottoms as small patches on the fringes of Plantago rigida bogs. The relevés which constitute the basis for the description of this variant were 10cated in the altitud in al range of 3800 m to 4200 m. Relevés with an important cover of Hypericum lancioides apparently represent a successional stage on old Werneria crassa cushions parallel to such series of succession described on Plantago rigida and Distichia cushions in the Colombian Eastern Cordillera (Cleef 1981; Bosman et al. 1993).

The paramo vegetation

A similar type of vegetation, but with another species of Werneria e.g. the vegetation of Oritrophio limnophili-Wernerietum pygmaeae subass. typicum, has been reported fram one 10cality in the Sierra Nevada de Santa Marta (Cleef & Rangel 1984). In Ecuador, Acosta-Solís (1984) found Werneria disticha, W graminifolia, W pumila, W pygmaea, W rigida and W rosea, on the volcanic sandy deposits of the Chimborazo V olcano. Monasterio (1980), referred to Werneria pygmaea cushions within the Plantago rigida bogs on glacial valley bottoms in the Sierra Nevada de Mérida, Venezuela.

Gentianello dasyanthae-Plantaginetum

rigidae Salamanca, Cleef & Rangel1992

Gentianella dasyantha-Plantago rigida cushion bog Turbera de cojines de Plantago rigida con Gentianella dasyantha

Type: relevé SS 1. Table 4; Photo 13-15; (see also vol.1, Photo 26, 31) Physiognomy: The bogs of this association include compact flat cushions, in which Plantago rigida attains between 20% and 100% cover. Tussocks ofPoaceae, grawing on top ofthe cushions, with cover between 1% and 30%, are characteristic. Some (dwarf) shrubs may be present with cover between 2 % and 50%. In appraximately half of the relevés, bryophytes were present; covering between < 1% and 60%. Composition and syntaxonomy: Diagnostic species ofthis association are Baccharis caespitosa, Bromus lanatus, Diplostephium eriophorum, Gentianella dasyantha, Hypericum laricifolium, Lachemilla galioides, Oreomyrrhis andicola, Pentacalia vaccinioides, P. vernicosa and Valeriana plantaginea. With the ex-

Photo 14. Cushion bog ofthe Gentianello dasyantha-Plantaginetum mo ofthe Parque Los Nevados.

rigidae association in the grass pára-

- Turbera de cojines perteniciente al Gentianello dasyanthae-Plantaginetum mente dicho del Parque Los Nevados.

rigidae en el páramo propia-

La vegetación de páramo

Photo 15. Cushion bog of Plantago rigida associated with bunches of Festuca sublimis (Gentianello dasyanthae-Plantaginetum rigidae) at 4200 m on the northwestern slope ofthe Nevado del Ruiz near Las Brisas (Caldas province). The volcanic outcrops support low shrubs of Loricaria colombiana (Compositae) and moss cover. - Turbera de cojines de Plantago rigida con pajonal de Festuca sublimis (Gentianello dasyanthae-Plantaginetum rigidae) a ca. 4200 m en el lado norte occidental del Nevado del Ruiz, cerca de Las Brisas (Dpto. de Caldas). Los afloramientos de roca volcánica están cubiertos de arbustillos de Loricaria colombiana (Compositae) y musgos.

ception of some of the character species for higher rank syntaxa, there are not many species in common with the diagnostic species given by Cleef (1981) for Hyperico lancioides-Plantaginetum rigidae of the paramos from the Eastern Cordillera of Colombia. Two subassociations are provisionally described within the present Gentianello dasyanthaePlantaginetum rigidae, the subassociation typicum, and the subassociation brometosum lanatae. Ihe first is poorer in species. Bromus lanatus, Elaphoglossum mathewsii, Hieracium avi/ae, Niphogeton dissecta, Pentacalia vernicosa, Senecio formosus and Valeriana plantaginea are differential for the subassociation brometosum lanatae. The association Gentianello dasyanthaePlantaginetum rigidae subass.typicum is characterized by the presence of Oreobolus cf. obtusangulus. Oreobolus obtusangulus, a common element of the Plantago rigida bogs in the Colombian Eastern Cordillera (Cleef 1978; 1981; Bosman et al. 1993), is very rare in the Ruiz-Tolima massif. Ihis cushion species was found only two times during the tieldwork: one record from the Páramo de Santa Rosa and another from the Quindío V oleano. It is supposed that the vo]canic environment, rich in nutrients, is limiting the presence of Oreobolus. Syneco]ogy and distribution: Cushion mires belonging to the association Gentianello dasyanthae-Plantaginetum rigidae are found in concave and flat glacial depressions in the paramo proper be]t. Plantago rigida cushion bogs occur in most Co]ombian paramos. Although apparently scarce in the Sierra Nevada de Santa Marta (there is on]y one observation: Sturm & Rangel 1985), they are wide]y distributed in the Eastern and in the Central Cordilleras and a]so occur in the Western Cordillera, the Tatamá massif and on the Farallones de Cali (Ca]derón 1993).

The parama vegetatian

Benoist (1935), Diels (1937), God]ey (1978), Acosta-Solís (1984) report Plantago rigida cushion bogs fram the paramos of Pichincha and Chimborazo, as well as from many other ]0calities in Ecuador. Also in Ecuador, Ramsay (1992) described aPlantago rigida cushion paramo fram 4200 m at the El Altar Volcano, Ecuador. In Central Peru, Gutte (1980) described an assaciation of Carex microglochin-Plantago rigida fram 3800-4800 m. This vegetation type has affinities with the Gentianello dasyanthae-Plantaginetum rigidae at syntaxonomica] ranks above the association leve], with species like Gentiana sedifolia, Luzula racemosa, Oritrophium limnophilum, Ourisia muscosa andWerneria pygmaea. Rivas-Martinez & Tovar (1982) described the same community of Centra] Peru as Hypselo reniformis-Plantaginetum rigidae, be]onging to the alliance Hypselo-Plantaginion rigidae (Calamagrostio jamesonii-Distichietalia muscoides MartÍnez & Tovar, l.c). Seibert & Menhofer (1992) studied a Calamagrostio ovataePlantaginetum rigidae fram the Bo]ivian Andes. Monasterio (1980) reported Plantago rigida bogs fram glacial valley bottams in the paramo belt ofthe Sierra Nevada de Mérida, Venezuela.

Sphagnum-Chorisodontium

bog

Sphagnum bogs appear to be rather rare in the Parque Los Nevados study area. This could be attributed ta the relatively nutrient rich volcanic substrates and low precipitation compared to paramo elsewhere in the Colombian Andes. Just one relevé (Table 4a), has been taken fram a species-rich Sphagnum-Chorisodontium bog with a substantia] open aerial cover af Calamagrostis effusa at 3710 m along the upper forest hne just below Hacienda La Sierra, above Termales de Santa Rosa de Cabal, on the west slope of the TPN transect.

Paramo scrub Apart fram the association Baccharido-Hypericetum community can be reported.

laricifolii described above, another scrub

Pentacalietum vernicosi Cleef 1981 carr. Salamanca, Cleef & Rangel 1992 Pentacalia vernicosa shrub Matorral de Pentacalia vernicosa Tab]e 2 Physiognomy: These shrub]ands of the high paramo proper exhibit three layers: - shrub ]ayer, covering between 20 and 75%, - tussock layer, covering between < 1 and 40%, - graund ]ayer, covering between < 1 and 30%. Sometimes bryophytes can dominate in the ground layer, reaching a cover as high as 80 %. Composition and syntaxonomy: This association was originally described as Senecionetum vernicosae by C]eef (1981) for the southern paramos of the Co]ombian Eastern Cordillera. Character species for the Centra] Cordillera include Senecio isabelis and S. latiflorus. Common species of this association to Centra] and Eastern Cordilleras are Calamagrostis recta, Campylopus spp., Geranium sibbaldioides, Lachemilla nivalis, Lachemilla holosericea, Leptodontium wallisii, Oreomyrrhis andicola, Pelti-

La vegetación de páramo

Table 4a.

Sphagnum-Chorisodontium

Relevé nr. Relevé area Slope (0) Exposure Altitude m cover %

65 10 3

1 1

5 1

5 2

1 <1

<1 <1 <1 <1 <1 <1+ <1+ 5

1 <1 <1 3 <1

1 <1 <1 <1 <1

bogo

AMC 608 6m x 6 m 3

SW 3710 vascular species: Calamagrostis effusa Espeletia aff. hartwegiana (yellowish broad-Ieaved) Hypericum laricifolium Oritrophium peruvianum Lycopodium d. brevifolium Festuca dolichophylla Isoetes andina Pernettya prostrata Uncinia macrolepis (U meridensis,) Lucilia kunthiana Senecio repens Hypochaeris sessiliflora Cotula minuta Lachemilla d. hispidula Sisyrinchium sp. (small, yellow flowering) Erigeron sp. Nertera granadensis Ophioglossum crotalophoroides Carex sp. (brownish, small) Hypericum lancioides Bartsia sp. Pedicularis in curva Werneria humilis Geranium sibbaldioides Ericaceae (unknown) Bromus sp. Azorella multifida Jamesonia rotundifolia. Plagiocheilus solivaeformis

Locality: Parque Los Nevadas, Risaralda Hacienda La Sierra; upper forest line 24 January 1980 microtopography: cover %

hummock-hollow

bryophytes & lichensl cryptogams:

40 10

Chorisodontium sp. Sphagnum magellanicum

<1 35 25 <1 2

Pezizales (orange) Plagiochila sp. Riccardia spp. Lepidozia sp. Anastrophyllum sp. Campylopus cucullatifolius Adelanthus lindenbergianus

2 <1+ <1+ 5 1

1 <1 <1+ <1+ 1

<1 <1 < 1+

Jensenia sp. Lophocolia sp. Campylopus spp. Herbertus sp. Metzgeria sp. Lejeuniaceae (Iight-greenish) Funaria calvescens Ascomycetes (yellowish) Pleurozium schreberi Leptodontium wallisii Cladonia subg. Cenomyce Leptoscyphus d. c1eefii.

gera spp., Satureja nubigena and Senecio formosus. Senecio niveo-aureus is found instead of Senecio isabelis in Pentacalietum vernicosi of the Co1ombian Eastern Cordillera (C1eef 1981). Synecology and distribution: Pentacalia vernicosa is a frequent companion of the Plantago rigida bogs. Scattered shrubs of this species are also characteristic for Calamagrostis recta bunchgrass1ands. Range1 & Lozano (1986) described the species as characteristic for the Calamagrostis macrophylla-C ejJusa and Chusquea (Swallenochloa) tessellata-Espeletia hartwegiana ssp. centroandina communities on the Puracé Volcano. Cleef (1981) reported the Pentacalietum vernicosi fram the southern paramos of the Co1ombian Eastern Cordillera, as a new association in the altitudinal range between 3800 and 4100 m.

"",l,--,l"•-•-•--,,l'-,•-,-,l'

,,l' -

PRADOS <1 ,1<1 lO ,1 23S 754S7" sS 1532 SE5 NEE <1<1 <l <1 741 4<1 ,1' ,1 1 <1 <1,1 <1 ,1 12S "60 025•19 ,l' <1 ,1<l<1'<1' ,1,1'O ,1<1 3720 C596 25 261S 21 2011 30 3311 60 <1 <1156 154 1,1 15 ,,_ 13e "12 1S 100 103 SI SIo 106 102 ,13 14 30 2,O 221 10 16o99 316 O 15 ,1 40 30 oe47S2 A 14 'O ,1-3 < s50 35 95 eo 70 96 90 P S ,,1750 O 3,1 21-615 40 60 16 '0 1302S 43 9NW S 760u 1<1 o10 564G 26 7SA52S 340111-WNW NW <1' C!577 <115 25 30 <1 15 <l524 33,1 115 ,1 C576 ,13<13SSI 1S <1 C624 512 531 4HUHLEN8ERGIETUH C61 ti 'O 514030 3950 13610 ,1 <1 3900 ,1I1IC:tOP'H'fL.LAE LACHEHILLETUI1 4200 4\50 3960 OUICULATAE 4150 3740 39t10 ,1-<1.0 992 es SS 2SI 414 •96 70 10 <1 <1 31,12S <1<12<1 <110 ,160 ,1 S4050 13775 AOItOSTIO 95 ,1 3600 StUBA", SREVICULHIS <1NW 20 <1 10 13 144 2S6 320 62 25 S SO 85 4S 529 54 72 'S 95 9S 75 1lO 15 60 O 5WW ,1 544 <1,1C15J4 S 3213C31 S·52 CI5J3 <l' 10 C452 CS1e C567 13S30 C106 IIJS 'O 00 SS 15 10 <1 <1 .•.•• C415 , 'O L. 3950 C336 C491 4040 23900 C320 C257 3960 ,1 e 4OtiO CI60 156 <1 3eoo 3640 C1501 3915 CS65 3ellO ,y 'u 'y 90 'y 11 2pS ,13670 r.STIGIAUE ENE ACIACHNETUH 20 4000 NNW ,1 <1 5433130 32150 <1nP'ICUH 70 S4070 7Q3e25 60ft'ULVfHATA( "<1 ,1-,1 3t1S0

11llhlenberglu

<1 ,,_

,130 <1 231

2 <1

<1-

15 15

fOS1l910l0

-l ::J" CD

al al

...,

3O < CD

CO CD

§: o· ::J

Buccrll~ns <1 212 <1 <1 <1<1 ID

•

10 lrlcune-oto 2<1 <1 <1<1 IS1

d-<1

,l' o

:J 2<1<1d "<1 <1

<1 <1

d I< 2 <1<1 2

,1 IS ID<11 <1 <'1

<11 <1

O: Q)3

d ,,-

(")

CO<1-

<1<1 Q). <1

•

<12

" • <11 1

<12

<1 <1

<1S

,,<l'<1 2 ""O

<1.

<1.2

The paramo vegetation

The association Pentacalietum vernicosi occurs in the study area between 4000 and 4400 m, either on the foot slopes of scree debris, near the boundary of the superparamo, or on the wet soils along small ravines in the high paramo proper. Paramo meadows A few types of azonal meadows will be described in the present study. Most of them be long to the alliance Lachemillion orbiculatae Cuatrecasas 1934, with the exception of the Muhlenbergietum jastigiatae Cleef 1981 (now Muhlenbergietum cleejii corro Salamanca et al., this study). The alliance Lachemillion orbiculatae Cuatrecasas 1934 includes most of the meadows with Lachemilla orbiculata as a prominent species. This taxon replaces the natural vegetation in the northem Andes mostJy by repeated buming and intensive grazing at the altitudinal limit of the Andean forest in the northem Andes.

Muhlenbergietum cleefii Cleef 1981 corro Salamanca, Cleef & Rangel (this study). Muhlenbergia c1eefiimeadow Prado de Muhlenbergia c1eefii Table 5 This association has been described by Cleef (1981) as Muhlenbergietum jastigiatae from the paramos of the Colombian Eastem Cordillera. These humid meadows composed of small cushions of Poaceae were observed in the damp soils transitional to Plantago rigida cushion bogs near the Otún lake at 3900 m. However, these have also been observed elsewhere in similar habitats. Diagnostic taxa of this association are Breutelia spp., Carex pichinchensis and Galium canescens. According to Laegaard (1995), the common Muhlenbergia cushiongrass species growing on damp soil in the Colombian paramos belongs to the newly described M. cleefii Laegaard, and not to M. jastigiata (Pres!) Henr., which is a misidentification. In the Parque Los Nevados study area also transitions have been noted from this association to Caricetum pichinchensis resulting in a Breutelia spp. facies and a Sphagnum cuspidatum facies of this species-poor vegetation type.

Aciachnetum acicularis Vareschi 1953 em. Cleef 1981; corro Salamanca, Cleef & Rangel, (this study). Aciachne acicularis meadow Prado de Aciachne acicularis Table 5 Composition and syntaxonomy: The vegetation of Aciachnetum acicularis is dominated by prickly cushion grasses, and was originally described as Aciachnetum pulvinatae from the Sierra Nevada de Mérida in Venezuela (Vareschi 1953). Laegaard (1987) studied the genus Aciachne, which was earlier believed to be monotypic with A. pulvinata. However, two new species were recognized by Laegaard (J.c.): A. acicularis and A. flagellifera. Aciachne acicularis has a wide distribution from Venezuela to Bolivia, and was also matched for the Los Nevados study area. The association Aciachnetum acicularis can be divided in two subassociations: typicum Cleef 1981 and lupinetosum microphylli Salamanca, Cleef & Rangel 1992 (type relevé AMC 634). The first subassociation is

La vegetación de páramo

restricted to the Aciachne acicularis meadows of the Colombian Eastem Cordillera, while the subassociation lupinetosum microphylli has been identified for the Ruiz- Tolima volcanic massif. Agrostis cf. haenkeana, Hypochoeris sessiliflora, Lachemilla orbiculata and Lupinus microphyl[usare mainly found in the subassociation lupinetosum microphylli. A diagnostic species for the Rujz area is Hypericum lancioides, while Calandrinia acaulis and Geranium sibbaldioides are found in the same association in the Eastem Cordillera (Cleef 1981). Synecology and distribution: In the Ruiz-Tolima massif, relatively big patches ofthe vegetation belonging to this association were observed on the dry and heavily grazed eastem slope ofthe Santa Rosa Volcano between 3800 and 4100 m, and in the headwaters of the Quebrada Africa on top of old lake sediments at 3800 m. Similarly Aciachne acicularis vegetation is reported for the paramos ofVenezuela (Vareschi 1953; 1970; Monasterio 1980; Berg 1998) and also for Costa Rica (Chaverri & Cleef 1996). In Peru (Gutte 1985) and Bolivia (Seibert & Menhofer 1991; 1992) Aciachne pulvinata ("Gnaphalio-Aciachnetum pulvinatae") vegetation is natural to the dry puna landscape. However, Laegaard (1987) indicated that Aciachne pulvinata and A. acicularis seem almost sympatric in Peru and Bolivia.

Agrostio breviculmis-Lachemilletum

orbiculatae Cleef 1981

Agrostis breviculmis-Lachemilla orbiculata herb field Prado de Lachemilla orbiculata with Agrostis breviculmis

Table 5 Physiognomy: These low herbaceous meadows are dominated by ground rosettes of Lachemilla orbiculata. In some cases small shrubs and/ or bryophytes can attain a high percentage of the total cover. The association was described for the Eastem Cordillera of Colombia (Cleef 1981). Composition and syntaxonomy: Poa annua, Taraxacum sp. andTrifolium repens are diagnostic taxa for the study area. In the Agrostio breviculmis-Lachemilletum orbiculatae meadows of the Central Cordillera, Agrostis cf. haenkeana is far more common than A. breviculmis. Synecology and distribution: The meadows of Agrostio breviculmis-Lachemilletum orbiculatae are found in the study area in deforested areas near the altitudinal Iimit of the high Andean forest, 01' as a replacement of tussock grasses in heavily grazed bunchgrassparamos. They occupy an altitude range from 3800 m to 4200 m and are widely distributed in the northem Andes.

Aquatic vegetation During fieldwork in the Otún area of the Parque Los Nevados, a number of quick relevés and observations were made on the aquatic vegetation (submerged and wet shore communities) of paramo lakes. This work included observations on the hydroseral sequence (Fig. 13). The highest lake (Fig. 13e) on the southwest slope ofNevado de Santa Isabel contained submerged vegetation (at 50 cm depth) of Isoetetum karstenii (Cleef 1981). Isoetes karstenii (identification confirmed by DI'. H.P. Fuchs 1980) covered 20% ofthe sandy lake bottom (rel. AMC 584). The association Isoetetum karstenii is here for the first time documented outside the Cor-

The paramo vegetation

c. 9

":'-,.~,~" •...• " ..•.:,.::.::- O ;.

.' .~~.•..;.,>:",:

-15' m.

4310m.

-1

1. Caricetum cf. pichinchensis with/con Lachemilla orbiculata, L. mandoniana, Veronica serpyllifolia, Cotula minuta, cf. Calliergonella sp., Poa annua. Apparently manuring by waterfowl/aparentemente deposición de estiercol por avifauna acuática; 2. Lilaeopsis schaffneriana, Limosella australis; 3. Isoetes sp.; 4. Alopecuris aequalis; 5. Myriophyllum quitense (with/ conPotamogeton berteroanos & filamentous green algae/algas verdes filamentosas; 6. Callitricha sp.; 7. Nitella sp.; 8. Lilaeopsis schaffneriana, Isoetes sp., cf. Fontinalis sp.; 9. Calamagrostis cf. ¡¡gulata; 10. Plantago rigida; 11. Distichia muscoides; 12. Ranunculus nubigenus; 13. Crassula pedicularis; 14. Isoetes karstenii; 15. upper bunch grass paramo/Pajonal paramo propiamente dicho withl con Draba sp.

Fig. 13. Semi-schematic hydroseral sequence of the vegetation in Laguna atún (a, b; 3975 m) and three smalllakes (e, d, e) at different altitudes (4150--4310 m) on the southwest slope ofNevado de Santa Isabel, Risaralda province. - Secuencia hidroseral semi-esquemática de la vegetación en la Laguna atún (a, b; 3975 m) y en tres lagunitas (e, d, e) a diferentes altitudes s.n.m. (4150--4310 m) en el lado suroccidental del Nevado de Santa Isabel, Dpto. de Risaralda.

La vegetación de páramo

dillera Oriental of Colombia. The species has been reported in Colombia (between about 3500 and 4425 m) and also for the Mérida Andes in Venezuela. In small lakes at 4260 m and 4150 m on the same slope (Fig. 13c, d) Isoetes karstenii was still present with low (l 0-15 %) cover. In these lakes it was found in association with Crassuletum peduncularis Cleef 1981 corro Cleef (this study). In the Colombian Eastern Cordillera this syntaxon has been earlier described as Tillaeetum paludosae Cleef 1981 (based on Tillaea paludosa Schltdl., now a synonym of Crassula peduncularis (Sm.) Meigen) with two subassociations: isoetetosum and typicum (Cleef 1981). For the time being we believe that the six Central Cordilleran AMC-relevés (4100-4170 m) belong to the same syntaxon as in the Eastern Cordillera of Colombia: Crassuletum peduncularis Cleef 1981 corr. Cleef (Table 5a). lA. Steyermark has later described a second species, Crassula (Tillaea) venezuelensis with a distribution area in the high Andes from Venezuela to Pem. We are not convinced that Crassula venezuelensis (Steyerm.) M. Bywater & Wickens is a 'good species', and maintain for the moment Crassula peduncularis for the study area. Hence, the community should be termed Crassuletum peduncularis, as the only syntaxon in this amphibious habitat on sandy-silty paramo lake shores. In Laguna Otún (Fig. 13a,b) a hydroseral sequence was studied from the swampy shores with mire and reedswamp vegetation (different communities of order Marchantio-Epilobietalia Cleef 1981) to submerged communities of Hydrocotylo ranunculoides-Myriophylletum quitensis Cleef 1981 corro Cleef and deep lake bottom stands belonging to Nitella sp.(Charetea). Patches of Alopecuris aequalis with filamentous algae and floating Azolla cf. filiculoides, Calamagrostis ligulata, Carex bonplandii, Caricetum pichinchensis Cleef 1981, Juncus sp. with Epilobium sp., Hydrocotyle ranunculoides, Lilaeopsis schajJneriana and Limosella australis have been recorded partly on mud, partly floating, on or close to the unsafe shores of Laguna Otún (3975 m).

10 70 0.5 594 622 0.5 2 615 4170 4160 50 581 2 580 25 42 20 65 35 90 15 30 125 <4160 1<80 10 1Cleef 1981 15 100 3 corro Cleef 616 4270 Table 5a. Crassu/etum pedicu/aris 615,616), Laguna de Silencio, Oitrichum Crassu/a pedicu/aris sp. (GVR 1226) East of Otún lake (AMC 622).

relevé nr. AMC sabel, SW slope (AMC 580,581,594),

NW slope El Portón (AMC

20 3

The paramo vegetation

Rheophytic vegetation bordering streams at 3730 m in the Quebrada Africa sector included small stands of Montia fontana (AMC 629) and Limosella australis (AMC 628). Limosella australis was further recorded (AMC 647) near the shore of Laguna del Silencio (4150 m) above Laguna OtĂşn. In shallow running water of Quebrada Totarito (3320 m) (AMC 628) and in Quebrada Las Damas (3030 m) (AMC 629) bryophyte growth of Rhynchostegium riparioides was noted on boulders with 80 and 30% cover respectively. The same species (cover 80 %) was also documented in Quebrada La Sierra near Hacienda La Sierra (3675 m) in the upper forest line (AMC 607). The species seems very common in this rheophytic habitat at the East slope (Tolima) and West slope (Risaralda) of the Parque Los Nevados. This rheophytic vegetation type was earlier reported from the lower paramos of the Eastern Cordillera of Colombia (Cleef 1981) as Dendrocryphaeo latifoliae-Platyhypnidietum riparioides Cleef & Gradstein 1981. At present the correct name for this association is Dendrocryphaeo latifoliae-Rhynchostegietum riparioides Cleef & Gradstein 1981 corro Cleef.

The superparamo From C. 4300 m upwards the vegetation cover starts to be more sparse; the absence of Calamagrostis recta, C. eJJusa and Espeletia hartwegiana is a noticeable feature of the superparamo. Similarly as in the Eastern Cordillera of Colombia (Cleef 1981) the superparamo zone of the Central Cordilleran study area can be subdivided into an upper (subnival) and a lower superparamo. Small tufts of Festuca breviaristata and Agrostis araucana that form the so-called blue grasslands (Cleef et al. 1983; Salamanca et al. 1992), are characteristic for the lower superparamo. Replacing the low Pentacalia vernicosa shrubs of the bunchgrassparamo, Loricaria columbiana is the most common shmb in the lower superparamo. Near the lower limit ofthe nival belt, the vegetation cover becomes increasingly scattered and only small patches of subnival vegetation are found. Calandrinia acaulis, Cerastium jloccosum, Draba spp., Erigeron chionophilus, Lachemilla nivalis, Pentacalia gelida and Senecio canescens are almost exclusive taxa to the superparamo. Distichia muscoides dominated cushion bogs are common in the lower superparamo.

Subnival communities The subnival communities are present at the altitudinallimit of the upper superparamo vegetation. They exhibit a pioneer character, are of variable t10ristic composition, and show conspicuous adaptations to the extreme environmental conditions (Monasterio 1980; Pfitsch 1988). The volcanic origin of the substrate, in combination with the diurnal freezing and thawing, have shaped unique habitats. The ongoing retreat of the glaciers is followed by colonization of the highly specialized vegetation. The sparse subnival vegetation is found on the coarse, and/or, fine-grained volcanic sandy deposits, where well-differentiated soils are not yet developed.

Syntaxonomy

of the subnival communities

Agrostio foliatae-Cerastion

floccosae Cleef, Salamanca

& Rangel all. nov.

AlIiance of Agrostis foliata and Cerastium floccosum Alianza de Agrostis foliata y Cerastium floccosum

Type: Cerastio floccosi-Pentacalietum Table 6

gelidae Salamanca, Cleef

& Rangel 1992

La vegetación de páramo

Physiognomy: The vegetation type ofthis al1ianee is dominated by searee, patehy, open vegetation ofthe lower and uppermost superparamo. This varies from dominanee of smalJ shrubs, whitish ground rosettes, loose grass tufts, sma11tussoeks and aeroearpous bryophytes and liehens. Bryophytes and liehens l11ayfreely move over the substrate as a eonsequenee of night1y frost heaving. Composition and syntaxonomy: Diagnostie taxa of the assemblage are Agrostis foliata, Baccharis caespitosa, Bromus lanatus, Cerastiumfloccosum, Draba hallii, D. hazenii, D. pachythyrsa, Erigeron chionophilus, Grammitis moniliformis, Hypochaeris sessiliflora, Luzula racemosa, Lycopodium crassum, Poa trachyphylla, Senecio canescens, Stereocaulon vesuvianum and Valeriana plantaginea. AIso the eharaeter species ofthe six associations, referred to below, have been included here. This classification is based on relevés from the study area; for a robust c1assification at the order and c1ass level, it is necessary to compare with superparamo elsewhere in the northern Andes. The assoeiation Racomitrio-Lachemilletum is the vegetation type with highest speeies density. In faet, this vegetation type is 10ca11ypresent on the lowermost border (4150--4250 m) of the superparamo. Racomitrium crispulum and Thamnolia vermicularis are present in both the associations Racomitrio-Lachemilletum nivalis and Thamnolio-Racomitrietum nivalis. Those may constitute either a suba]]iance, or final1y merge into one association (Thamnolio-Racomitrietum prov.), when more relevés become available. Cuatrecasas (1934) described 'Culcitietum rufescentis-Agrostiosum' from the Tolima Volcano. In this syntaxon, he integrated a11zonal superparamo vegetation types from the Loricaria colombiana scrub at 4320 m up to the last stands at 4500 m (see Cuatrecasas, this volume). Syneeology and distribution: This type of superparamo is representative for the Parque Los Nevados area. As detailed for the Mérida Andes by Pfitsch (1988) daily frost heaving and low temperatures, combined with high radiation levels, are the main abiotic factors. On the Puracé V olcano, some of the associations belonging to this a11iance seem also to be present (Rangel & Lozano 1986). In the study area, coml11unitiesofthis alliance extend between about 4150 m and 4600 m. Cerastiofloccosi-Pentacalietum gelidae Salamanca, Cleef Subnival Pentacalia gelida dwarf shrub Matorral bajo subnival de Pentacalia gelida Type: relevé SS 63. Table 6; Photo 16

& Rangel1992

Physiognomy: This open, dwarf shrub-like, vegetation consists only of one sparse layer, about 30 cm high, mainly cOl11posedof endemic Pentacalia gelida, with sma]] eoriaceous leaves, covering between 1% and 70 %. Composition and syntaxonomy: Within this assoeiation two different variants can be recognized: one speeies poor, almost entirely consisting of Pentacalia gelida (variant inops, type relevé SS 63), and another relatively species rich (variant of Stereocaulon vesuvianum, type relevé SS 102). Synecology and distribution: This vegetation is found on pyroclastic flow deposits affected by diurnal freezing and thawing. The environment is permanent1y wet and cold, and the sandy deposits move according to erionival proeesses. The dwarfshrub of Cerastio-Pentacalietum gelidae was found in the Ruiz-

The paramo vegetation

Photo 16. Subnival dwarfshrub patches of Pentacalia gelida (Cerastiofloccosi-Pentacalietum gelidae) in the upper superpáramo ofthe Nevado del Ruiz, 'arenal' ofthe La Olleta volcano at 4650 m (Caldas province). The dwarfshrubs are characterized by dark green, coriaceous leaves and a well developed root systemo The substrate consists of moving ash deposits with stripes caused by solifluction and frost heave (relevé Cleef & Salamanca 610). - Vegetación subnival en islotes de arbustillos de Pentacalia gelida (Cerastio floccosi-Pentacalietum gelidae) en el superpáramo alto del Nevado del Ruiz, arenal de La Olleta, a 4650 m (Dpto. de Caldas). Los arbustillos se caracterizan por sus hojas coriáceas verdes y un sistema radicular bien desarollado. En el substrato de cenizas móbiles se oberservan las huellas del efecto combinado de la soliflucción y la gravedad (lev. Cleef & Salamanca 610).

Tolima massifbetween 4400 and 4650 m. The variant inops belongs to the uppermost vegetation limit, while the variant of Stereocaulon vesuvianum can be found at somewhat lower altitudes. No similar association has been described for other studied superparamos of Colombia, such as the Eastern Cordillera or the Sierra Nevada de Santa Marta. Nevertheless, some ofthe species like cf. Oreoweisia bogotensis, Senecio canescens and Thamnolia vermicularis, occasional in Cerastio-Pentacalietum gelidae, are reported to be common in the superparamo communities described by Cleef (1981) for the Colombian Eastern Cordillera. It is interesting to note that dwarshrub of Pentacalia (Senecio) guicanensis, a vicariant community occurs un del' similar environmental conditions in the Sierra Nevada del Cocuy.

Senecioni latiflori-Calamagrostietum Subnival Senecio latiflorus-Calamagrostis Vegetación subnival de Senecio latiflorus

ligulatae Salamanca, Cleef & Rangel 1992 ligulata vegetation y Calamagrostis ligulata

Type: relevé AMC 590. Table 6; Photo 17 Physiognomy: This vegetation is composed of scattered ground rosettes of Senecio latiflorus together with small cushions of Werneria humilis and tussocks of Calamagrostis ligulata.

La vegetación de páramo

Two ]ayers are present; - tussock ]ayer, with cover of Calamagrostis ligulata ranging between 5 and 80%, - ground layer, main]y composed ofthe cushions of Werneria humilis, with cover between 3% and ]5%. Bryophytes may cover as much as 90% in the ground ]ayer. Composition and syntaxonomy: Diagnostic species of this association are Calamagrostis ligulata, Lucilia kunthiana, Senecio latiflorus and Werneria humilis .. The association of Senecioni latiflori-Calamagrostietum ligulatae has t10ristic affinities with some of the communities with Calamagrostis ligulata described by C]eef (1981) for the high paramos ofthe Colombian Eastern Cordillera, viz. the Sierra Nevada del Cocuy and the Nevado de Sumapaz. A]so, site conditions on wet 01'damp ground are are indicative to azonal vegetation. For practica] reasons, the association of Senecioni-Calamagrostietum ligulatae is being provisionally included under the alliance Agrostio-Cerastion jloccosae. Note: The formal name of this association was erroneously omitted at the base of p. 57 in Salamanca (1992). The name of this association however was correctly quoted on p. 58 under 'Composición y sintaxonomía'. Synecology and distribution: Vegetation belonging to this association is present on humid coarse-grained volcanic sands, in depressions in small ravines in the high superparamo, between 4400 and 4500 m, in the Parque Los Nevados. In fact, this vegetation type is rather azona] than zonal.

Photo 17. Vegetation of Calamagrostis liguiata and ground cover of Bryum sp. (Cleef 10432) (Senecioni latiflori-Calamagrostietum ligulatae) at 4470 m in the upper superpáramo ofthe western slope ofthe Ne-

vadodel Ruiz (Caldas province). The small valley bottom between both moraines is permanently wet as a resultof seepage fram the surrounding slopes (relevé Cleef & Salamanca 612). - Vegetaciónde Calamagrostis ligulata y tapetes de Bryum sp. (Cleef 10432) (Senecioni latiflori-Calamagrostietum ligulatae) a 4470 m en el superpáramo alto dellado occidental del Nevado del Ruiz (Dpto. deCaldas).En el vallecito entre las dos morrenas hay escolTentíapermanente (lev. Cleef & Salamanca 612).

Senecioni canescentis-Cerastietum

The paramo vegetation

floccosi Salamanca, Cleef

& Rangel 1992

Senecio canescens-Cerastium floccosum superparamo vegetation Vegetación subnival de Senecio canescens y Cerastium floccosum

Type: relevé SS 139. Table 6; Photo 18-23; (see also vol. 1, Photo 8, 9) Physiognomy: This association consists of very sparse superparamo vegetation at the lower limit of the snow line. The total cover ranges fram 5% to 20%. Composition and syntaxonomy: Cerastium jloccosum, Poa trachyphylla andSenecio canescens are diagnostic species. This syntaxon is poor in species, with an average of only 5 vascular species. The Senecioni-Cerastietum is differentiated against all other here studied subnival associations by the absence of their respective diagnostic species. Distribution and synecology: Subnival vegetation of Senecioni canescentis-Cerastietum jloccosi occurs in the loose, not yet stabilized, sandy volcanic deposits, but also covers superparamo morraines (TPN 2). This vegetation was found between 4400 and 4550 m; mainly on the slopes ofthe Ruiz and Santa Isabel volcanoes. Superparamo vegetation, with Senecio canescens and Poa paucijlora, is also described by Rangel & Lozano (1986) fram Puracé Vo1cano. The next syntaxa do not properly belong to the subnival belt, but are characteristic of the transition subnival - lower superparamo blue grasslands. There they occur on the lava escarpments, in contact with the blue grasslands.

Photo 18. Whitish ground rosettes of Senecio canescens (Senecioni canescentis-Cerastietum jloccosi) at 4570 m in the upper superpáramo ofNevado del Ruiz, 'arenal' ofLa Olleta, constituting the almost upper limit of vascular plant growth (Caldas province). The substrate consists of unstabilized volcanic sand and ash deposits that are subjected to daily solifluction. The snow patches persist only few hours in the shadow ofthe rosettes (relevé Cleef & Salamanca 611). - Rosetas blancas acaules de Senecio canescens (Senecioni canescentis-Cerastietumfloccosi) en el límite altitudinal de la vegetación vascular en el superpáramo alto del Nevado del Ruiz, arenal de La Olleta, a 4570 m (Dpto. de Caldas). El substrato consiste de depósitos de arenas volcánicas sueltas, todavía no estabilizados, debido a la acción diaria de la soliflucción. Los parches de nieve persisten unas horas en la sombra de las rosetas (lev. Cleef & Salamanca 611).

La vegetación de páramo

Photo 19. Vegetation aspect of the upper superpáramo with ground rosettes of Senecio canescens (Senecioni canescentis-Cerastietumjloccosi) at the high pass (4550 m) between the voJcanic cones ofNevado del Ruiz and La Olleta (Caldas province). - Aspecto de la vegetación del superpáramo alto con rosetas esparcidas de Senecio canescens (Senecioni canescentis-Cerastietumjloccosi) en el paso alto (4550 msnm) entre el edificio principal del volcán del Ruiz y su cráter adventicio La Olleta (Dpto. de Caldas).

Photo 20. Upper limit of the vascular vegetation at about 4600 m on La Olleta (Nevado de Ruiz, Caldas province). Whitish ground rosettes of Senecio canescens (Senecioni canescentis-Cerastietum jloccosi) are growing together with dark, greenish, dwarfshrub of Pentacalia gelida on the unstable 'arenales' ofthe upper superpáramo. - Limite altitudinal de la vegetación vascular a ca. 4600 m en La Olleta (Nevado de Ruiz, Dpto. de Caldas). Observan rosetas blancas acaules de Senecio canescens (Senecioni canescentis-Cerastietum floccosi) creciendo junto con arbustillos verde oscuro de Pentacalia gelida en los arenales mobiles del superpáramo alto.

The paramo vegetation

Photo 21. Draba pennell-hazenii shown as tiny stem rosettes colonizing the unstable 'arenales' perpáramo at 4350 m on the northwestern side ofthe Nevado de Ruiz (Caldas province).

ofthe su-

- Draba pennell-hazenii en forma de caulirrósula pequeña que coloniza los arenales del superpáramo a 4300 m en el flanco norte occidental del Nevado Ruiz (Dpto. de Caldas).

Photo 22. Branched stem rosette up to 20 cm height ofyellow-flowered Draba pennell-hazenii at 4350 m in the shelter ofvolcanic outcrops in the superpáramo ofthe northwestern side ofNevado de Ruiz (Caldas province). - Caulirrósula ramificada de Draba pennell-hazenii (hasta 20 cm) en un abrigo de roca volcánica en el superpáramo a 4350 m, flanco norte occidental del Nevado de Ruiz (Dpto. de Caldas).

La vegetación de páramo

':;:':~~::~:~: :~'.:'~': ,- u_·

::,'2':'~';%;~;~f\::'~ ·i:

Photo 23. Superpáramo vegetation at 4350 m in a landscape ofmobile

'arenales' (caused by daily solifluction) and volcanic outcrops on the nOlihwestern side ofthe Nevado de Ruiz (Caldas province). Vegetation comprises low shrub of Loricaria coLombiana, bunches of Festuca sp., reddish Lycopodium (Huperzia) crassum and grayish patches of StereocauLon vesuvianum. - Vegetación de superpáramo a 4350 m en paisaje de arenales móbiles (con soliflucción diaria) y afloramientos de roca volcánica en el lado norte occidental del Nevado de Ruiz (Dpto. de Caldas). Se encuentran tambien arbustillos de Loricaria coLombiana, macollas solitarias de Festuca sp., tallos rojizos de Lycopodium (Huperzia) crassum y parches grisáceos de Stereocaulon vesuvianum.

Elaphoglosso mathewsii-Muehlenbeckietum

vulcanicae Salamanca, Cleef & Rangel 1992

Elaphoglossum matthewsii-Muehlenbeckia vulcanica vegetation Vegetación de Elaphoglossum matthewsii and Muehlenbeckia vulcanica

Type: relevé AMC 586. Table 6; Photo 24 Physiognomy: This vegetation consists oftwo layers: the first one, 15 cm high, is mainly composed ofthe fern Elaphoglossum mathewsii with cover between 2 and 20%. Predominant in the ground layer are the lichen Stereocaulon vesuvianum and the small creeping Muehlenbeckia vulcanica, with coverages for both species from 15 to 40%. Composition and syntaxonomy: Muehlenbeckia vulcanica is the exclusive character species for this association. Elaphoglossum mathewsii is also highly diagnostic fOl'this association, which is rather poor in species. Ground rosettes of Senecio canescens and Hypochaeris sessiliflora are absent Synecology and distribution: The asociation of Elaphoglosso mathewsii-Muehlenbeckietum vulcanicae is found within three different habitats: on the outcrops of volcanic andesites, on 10w stony ground moraines, and in coarse-grained pyroclastic flow deposits. In the Ruiz- Tolima volcanic massif, vegetation patches ofthis association were observed fringing the 10wermost superparamo between 4250 and 4380 m.

Photo 24. Fems of Elaphoglossum

The paramo vegetation

mathewsii (Elaphoglosso

mathewsii-Muehlenbeckietum

vulcanicae)

growing at 4375 m between volcanic roche moutonnée in the transition between the 'blue grassland' ofthe lower superpáramo and the subnival vegetation at the southwestern side ofvolcano Sta. Isabel (type relevé Cleef & Salamanca 586; Risaralda province). vulcanicae) a 4375 - Helechos de Elaphoglossum mathewsii (Elaphoglosso mathewsii-Muehlenbeckietum m en los afloramientos de roca volcánica pulida por acción del hielo en la transición entre los pastizales azules del superpáramo bajo y la vegetación subnival del superpáramo alto en el lado SW del Volcán de Sta. Isabel (lev. tipo Cleef & Salamanca 586; Dpto. de Risaralda).

Racomitrio crispuli-Lachemilletum

nivalis Salamanca, Cleef & Rangel 1992

Racomitrium crispulum-Lachemilla nivalis vegetation Vegetación de Racomitrium crispulum y Lachemilla nivalis

Type: relevé AMC 642. Table 6. (see also Cleef 1981, Fig. 29) Physiognomy: This association is composed ofhanging carpets ofmosses and low (up to about 30 cm) grayish ground rosettes on outcrops ofvoIcanic rocks exposed to frequent fog and atmospheric humidity. This results from the uppermost condensation zone at this altitude. Composition and syntaxonomy: Diagnostic species are Aa (Altensteinia) cf. colombiana, Castilleja jissifolia, Disterigma empetrifolium, Hieracium avilae, Lachemilla nivalis, Ourisia chamaedrifolia, Polystichum polyphyllum and Racomitrium crispulum (generally cover from 40 to 70%). Also diagnostic is the absence of Cerastium floccosum and Senecio canescens. Racomitrium lanuginosum and Rhacocarpus purpuracens reported by Cleef(1981) as character species for a similar Racomitrium crispulum vegetation type in the Colombian Eastem Cordillera, are found only in the plot of the type relevé (Racomitrium lanuginosum 30% cover). This association shows affinities with that of Loricarietum complanatae racomitrietosum crispuli Cleef 1981 ofthe Eastem Cordillera.

La vegetación de páramo

Synecology and distribution: The bryophyte vegetation belonging to Racomitrio crispuli-Lachemilletum nivalis was studied at the humid, exposed northwest side ofthe Ruiz Volcano within a narrow altitudinal range from 4150 to 4250 m. Patches have also been observed on the west slopes of the Santa Rosa and the Santa Isabel voleanoes. Rangel & Lozano (1986) reported patches of Racomitrium crispulum at 4250 m on the Puracé Voleano. Another stand belonging to this association was recorded at 4100 m on the Nevado de Sumapaz, Eastern Cordillera, as was referred to by Cleef(l98l) under 'Other zonallower superparamo communities'.

Thamnolio vermicularis-Racomitrietum

crispuli Salamanca, Cleef & Rangel1992

Thamnolia vermicularis-Racomitrium crispulum pioneer vegetation Vegetación pionera de Thamnolia vermicularis y Racomitrium crispulum

Type: relevé SS 104. Table 6; Photo 25 Physiognomy: The physiognomy of this vegetation is similar to that of the ground layer of the Racomitrietum crispuli-Lachemilletum nivalis described above. The conspicuous moss layer covers between 40 and 95%. A low herb layer, with cover from 2 to 30%, is also present. Composition and syntaxonomy: The poorness in species diversity is a diagnostic character when compared to the previously described Racomitrietum crispuli-Lachemilletum nivalis. Thamnolia vermicularis is a free moving lichen species common to both associations with Racomitrium crispulum, described here. Thamnolio vermicularis-Racomitrietum crispuli has affinities with the community of Thamnolia vermicularis-Alectoria cf. ochroleuca described by Cleef (1981) from the paramos ofthe Eastern Cordillera, although the latter one is richer in lichens. Both vegetation types have Thamnolia vermicularis and Draba spp. in common.

Photo 25. Detail (ofPhoto 23) showing patch of Stereocaulon vesuvianum (lichens) associated with Racomitrium crispulum (dark mosses), grasses and a small dwarfshrub of Loricaria columbiana. - Detalle de la foto 23. Parche en el cual predomina Stereocaulon vesuvianum (líquenes), asociado con Racomitrium crispulum (musgos oscuros), gramíneas, y un arbustillo de Loricaria columbiana.

The paramo vegetation

Synecology and distribution: The association of Thamnolio vermicularis-Racomitrietum crispuli is found on andesite outcrops ofthe lower superparamo. The vegetation starts growing in small depressions in the rocks, where litter, as wel! as fine-grained ashes, are accumulated. When the vegetation is well developed, large carpets of mosses hang over the vertical rocky wal!s. These are kept permanently wet by seepage from ground water. In the study area this association was found between 4200 and 4450 m. Rangel & Lozano (1986) reported the occurrence of Racomitrium crispulum in the superparamo of the PuracĂŠ V olcano from 3960 to 4250 m. But, according to these authors, these vegetation types are very scarce and were mainly found on volcanic sand deposits. Similar moss vegetation associations (between 3400-3800 m), with Grammitis moniliforme, Racomitrium crispulum, R. lanuginosum and Stereocaulon vesuvianum have been studied by Chaverri & Cleef (1996) from paramo outcrops in Costa Rica. AIso, patchy vegetation with Racomitrium lanuginosum var. pruinosum have been reported growing in the volcanic rock crevices from the summit of Mt. Mauna Loa (Hawaii) at 4150 m (Fosberg, 1959). VillagrĂĄn (1980) studied extense Racomitrium lanuginosum vegetation on the Osomo Volcano in Chile.

Superparamo

blue grasslands

This plant formation contains al! the grasslands of the lower superparamo belt. In contrast with the subnival vegetation, they always occur on the so-called fine-grained volcanic ashes (Kloosterman et a!., chap. 5, this vo!.).

Syntaxonomy

of the superparamo

Festuco breviaristatae-Agrostion

blue grasslands

araucanae Cleef, Salamanca

& Rangel al!. nov.

Alliance of Festuca breviaristata and Agrostis araucana Alianza de Festuca breviaristata y Agrostis araucana

Type: Lupino alopecuroides-Agrostietum Table 7

araucanae Salamanca, Cleef & Rangel 1992

Physiognomy: The aspect of the vegetation of this alliance is an open grassland, consisting of low tufts with a bluish hue. The open ground 1ayer consists of ground rosettes, small herbs and prostrate dwarf shrubs. Conspicuous are whitish inflorescences of Lupinus alopecuroides and Senecio canescenso Reddish clumps of Lycopodium (Huperzia) crassum locally reach high densities. Composition and syntaxonomy: Agrostis araucana and Festuca breviaristata are diagnostic species ofthis al!iance, characterized by high presence and cover values. The same applies for Bromus lanatus, Cerastium jloccosum, Erigeron chionophilus, Hypochaeris sessiliflora, Lachemilla nivalis, Luzula racemosa, Lycopodium (Huperzia) crassum, Senecio canescens, Stereocaulon vesuvianum and Valeriana plantaginea. The new alliance includes Lupino-Agrostietum araucanae, Baccharido-Agrostietum araucanae and provisionally Diplostephio-Loricarietum columbianae. Synecology and distribution: The so-called 'blue grasslands' are present in the lowermost part ofthe superparamo belt, where the vegetation cover may be close to 100%. Frost heaving is an important daily phenomenon here, but also pedogenetic processes develop under the closed tussock layer. The first species

La vegetación de páramo

indicative of grassparamo indicate, that this grass vegetation is transitional between the superparamo being dominated by large patches ofbare ground, and the bunchgrassparamo proper. In the study area, small tussock grasslands of Festuco-Agrostion araucanae are found between c. 4300 and 4470 m. Observations from Acosta-Solis (1984) indicate that this vegetation type may a1sobe present in the Ecuadorian Andes. Cleef et al. (1983) studied a superparamo blue grassland of Agrostis araucana and Festuca breviaristata with Lupinus alopecuroides, Lycopodium crassum and Senecio canescens which, though it was not ranked at the time, also belongs to this alliance. No similar superparamo blue grasslands have been described from the other two Colombian Cordilleras, nor from the Sierra Nevada de Santa Marta. Agrostis araucana has been reported (according to herbarium records) from Colombia to Chile and Festuca breviaristata as far south as Bolivia (Jorgensen & Ulloa Ulloa 1994).

Lupino alopecuroides-Agrostietum araucanae Salamanca, Cleef & Rangel1992 Agrostis araucana blue grassland with Lupinus alopecuroides Pastizal azul de Agrostis araucana con Lupinus alopecuroides Type: relevé TPN 22. Table 7; Figs. 14, 15; Photo 26-33; (see also vol. 1, Photo 10, 11) Physiognomy: This vegetation consists of two layers; - tussock layer, mainly composed of Agrostis araucana tufts, and some ground rosettes. The cover ranges from 20 to 70%. Conspicuous are the woolly columnar inflorescences of Lupinus alopecuroides, - ground layer of small herbs, achieving maximally 15 % of the total cover. Composition and syntaxonomy: Diagnostic species of this association are Draba hallii, Gentiana sedifolia, Lucilia kunthiana, Lupinus alopecuroides, Poa trachyphylla, Senecio isabelis, S. latiflorus and S. repens. Further also: Bartsia sp., Draba lindenii, Halenia campanulata, Lachemilla holosericea, Lysipomia museoides, Senecio summus, Valeriana plantaginea and Werneria humilis. The association has clase affinities to Baccharido-Agrostietum araucanae. Synecology and distribution: The association Lupino alopecuroides-Agrostietum araucanae was studied on the fine-grained sandy deposits ofthe lower superparamo on the Santa Isabel Volcano, between 4350 and 4500 111. This vegetation type is very common in the Parque Los Nevados. Rangel & Lozano (1986) and Duque & Rangel (1989) reported lower superparamo grasslands (3950 to 4380 m) withLupinus alopecuroides and Valeriana microphylla on the Puracé Volcano. However, Agrostis araucana was very sparse and Festuca breviaristata was absent.

Baccharido caespitosae-Agrostietum araucanae Salamanca, Cleef & Rangel 1992 Agrostisaraucana blue grassland with Baccharis caespitos a Pastizal azul de Agrostis araucana con Baccharis caespitosa Type: relevé SS 3. Table 7

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The parama vegetatian

TPN 28 4475 m

Fig. 14. Zonallower superpáramo ofblue grassland of Lupino-Agrostietwn araucanae at 4475 m northeast ofthe pass on the southeast slope ofNevado de Santa Isabel, Quebrada Africa (relevé TPN 28), Tolima province. See Photo 30 and 31. - Pastizal azúl zonal del superpáramo bajo del Lupino-Agrostietum araucanae a 4475 !TI al nOlieoccidente del paso al suroriente del Nevado de Santa Isabel, Quebrada Africa (lev. TPN 28), Dpto. del Tolima. Véase Foto 30 y 31. TPN 118 4460 m

Fig. 15. Semi-schematic cross-section of lower superparamo vegetation of low scrub (Diplostephio eriophori-Loricarietum colombianae) in contact with 'arenales' and different facies of blue grassland (LupinoAgrostietum araucanae) in the summit area at 4460 m at the northwest side ofSanta Rosa volcano, Risaralda province. - Corte semi-esquemático de la vegetación del superpáramo bajo con matorral bajo (Diplostephio eriophori-Loricarietum colombianae) en contacto con arenales y diferentes facies del pastizal azul (Lupino-Agrostietum araucanae) en la zona del cumbre a 4460 m en el flanco norteoccidental del Volcán de Santa Rosa, Dpto. de Risaralda.

Physiognomy: This vegetatian is mainly stratified into two layers; - tussock layer covering between 10 and 70%, - ground layer, covering from 3 to 25%, consisting of ground rosettes and prostrate dwarf shrubs. Sometimes scattered shrubs of Pentacalia gelida can be observed.

La vegetación de páramo

Photo 26. Blue grassland belonging to the Lupino alopecuroides-Agrostietum araucanae the lower superpáramo ofLagunares de Santa Isabel at about 4300 m. (Tolima province).

- Pastizal azul perteneciente al Lupino alopecuroides-Agrostietum Lagunares de Sta. Isabel a ea. 4300 m (Dpto. del Tolima).

association in

araucanae en el superpáramo bajo de

Photo 27. Zonal and azonal superpáramo

vegetation at 4300 m in the area ofLagunares de Sta. Isabel (Tolima province). Blue grasslands of Lupino alopecuroides-Agrostietum araucanae comprised Agrostis araucana, Festuca breviaristata and Senecio canescens. Lycopodium (Huperzia) crassum is present on the low morraines and on a cushion bog of Distichia muscoides (Floscaldasio hypsophilae-Distichietum muscoides) in the glaciallake. - Vegetación zonal y azonal del superpáramo a c. 4300 m en Lagunares de Sta. Isabel (Dpto. del Tolima). Pastizales azules de Lupino alopecuroides-Agrostietum araucanae con Agrostis araucana, Festuca breviaristata y Senecio canescens. Lycopodium (Huperzia) crassum sobre morrenas bajas y por encima de cojines de Distichia muscoides (Floscaldasio hypsophilae-Distichietum muscoides) en la laguna glaciar.

The paramo vegetation

Photo 28. Uppermost fringe of the blue grassland (Lupino alopecuroides-Agrostietum araucanae) of the lower superpáramo at 4450 m on a recent moraine on the northwestern slope ofNevado Sta. Isabel (relevé TPN 3; Risaralda province). - Franja superior del pastizal azul (Lupino alopecuroides-Agrostietum araucanae) del superpáramo bajo sobre una morrena reciente a 4450 m en el lado norte occidental del Nevado de Sta. Isabel (lev. TPN 3; Dpto. de Risaralda).

Photo 29. Blue grassland (Lupino alopecuroides-Agrostietum araucanae) of the lower superpáramo at 4550 m on the eastern side ofthe surnmit area ofvolcano Sta. Rosa (Risaralda province). Conspicuous are the whitish ground rosettes of Senecio canescens and reddish plants of Lycopodium (Huperzia) crassum (relevé TNP 8). - Pastizal azul (Lupino alopecuroides-Agrostietum araucanae) del superpáramo bajo a 4550 In en la zona oriental de cumbre del Volcán de Sta. Rosa (Dpto. de Risaralda). Son notorias las rosetas blancas acaules de Senecio canescens y los tallos rojizos de Lycopodium (Huperzia) crassum (lev. TPN 8).

La vegetación de páramo

Photo 30 and 31. Blue grassland (Lupino alopecuroides-Agrostietum

araucanae) ofthe lower superpáraal 4475 m in the headwaters of Quebrada Africa, northeast of the pass located southeast ofNevado Sta. Isabel (relevé TPN 28; Tolima province). See Fig. 14.

1110

- Pastizal azul (Lupino alopecuroides-Agrostietum araucanae) del superpáramo bajo a 4475 m al norteoriente del Paso, al suroriente del Nevado de Santa Isabel en las cabeceras de la Quebrada Africa (lev. TPN 28; Opto. del Tolima). Véase Fig. 14.

The paramo vegetation

Photo 32. Blue grassland (Lupino alopecuroides-Agrostietum araucanae) ofthe lower superpáramo close to the pass between the valleys of Qtún and Quebrada Africa, southeast of Nevado Sta. Isabel at 4380 111 (Risaralda province). A species poor variant of the Lupino-Agrostietum araucanae association covers the flat sandy bottom ofthe former glaciallake (4335 m) surrounded by moraines on the Qtún side ofthe pass.

- Pastizal azul (Lupino alopecuroides-Agrostietum araucanae) del superpáramo bajo cerca del Paso a 4380 m al suroriente del Nevado de Santa Isabel, entre los valles de Qtún y Quebrada Africa (Dpto. de Risaralda). Se encuentra una variante más pobre en especies de la asociación Lupino-Agrostietum araucaneae en el fondo plano y arenoso de una antigua laguna glaciar (4335 msnm) rodeada por morrenas en el lado occidental del Paso.

Composition and syntaxonomy: Baccharis caespitosa val'. alpina, Pentacalia gelida, Lupinus microphyllus, Geranium sibbaldioides, Rumex acetosella, Hieracium avilae, Eryngium humile and Ranunculus praemorsus are diagnostic species. The association also includes a Gentianella dasyantha variant (val'. nov.; type rel. S 67) with most ofthe diagnostic species for the association and a species pOOl'variant, variant typicum (val'. nov.; type rel. S 65). The association Baccharido-Agrostietum araucanae shows close affinities with LupinoAgrostietum araucanae, but also with Diplostephio eriophori-Loricarietum colombianae. Baccharis caespitosa, Geranium sibbaldioides, Lupinus microphyllus and Pentacalia gelida occur in both vegetation units. Synecology and distribution: The association Baccharido caespitosiae-Agrostietum araucanae was studied on the sandy volcanic deposits affected by periglacial processes. The association reported here is on the lower superparamo ofthe Ruiz, the Santa Isabel and the Santa Rosa volcanoes, between 4200 and 4400 lll.

La vegetación de páramo

Photo 33. Blue grassland (Lupino alopecuroides-Agrostietum araucanae) of the lower superpáramo on sandy ridges on the glacier valley bottom at 4335 m directly west ofthe pass between the Otún valley and Quebrada Africa, southeast ofNevado de Santa Isabel (Risaralda province). Very conspicuous are the reddish Lycopodium (Huperzia) crassum plants between the low tussocks. In the background, Polylepis sericea dwarfforest is present (details photos I and 2). - Pastizal azul (Lupino alopecuroides-Agrostietum araucanae) del superpáramo bajo arenosos en el fondo del valle glaciar a 4335 m, inmediatamente al W del Paso entre los de la Quebrada Africa, al suroriente del Nevado de Sta. Isabel (Dpto. de Risaralda). Son plantas rojizas de Lycopodium (Huperzia) crassum en el pajonal ralo y bajo. En el fondo bosque de Polylepis sericea , el cual se muestra en detalle en las fotos 1 y 2.

Diplostephio eriophori-Loricarietum

columbianae Salamanca, C1eef

sobre depósitos valles de Otún y muy notorias las del valle hay un

& Rangel1992

Loricaria columbiana shrub with Diplostephium eriophorum Matorral bajo de Loricaria columbiana con Diplostephium eriophorum

Type: relevé AMC 593. Table 7; Figs. 12,15; Photo 34-36 Physiognomy: This open scrub is composed of two layers; - shmb layer of greenish-brawn strong1y imbricate leaves, c. 50 cm high, covering between 15 and 90%, - ground layer, with a cover up to 30%. Composition and syntaxonomy: Loricaria columbiana, Arcytophyllum cf. aristatum, Calamagrostis ejfusa, Diplostephium eriophorum, Jamesoniella rubricaulis, cf. Oreoweisia bogotensis, Pernettya prostrata, Polystichum polyphyllum, pottiaceous mosses, Racomitrium crispulum, Riccardia spp., Tortula andicola and Vacciniumfloribundum are diagnostic taxa of this association. This syntaxon shows strong floristic affinities with some ofthe syntaxa grauped under the subnival vegetation; especially with Thamnolio vermicularis-Racomitrietum crispuli and with Racomitrio-Lachemilletum nivalis. This is indicated by the presence of Disterigma empetrifolium, Lachemilla nivalis, cf. Oreoweisia bogotensis, Polystichum polyphyllum. and Racomitrium crispulum. Among the species in common between Loricarietum complanatae described by Cleef (1981) fram the Co10mbian

The paramo vegetation

Photo 34. Landscape of the lower superpáramo with outcrops of volcanic rock and 'arenales' (unstable sandy and ash deposits) at about 4350 m on the northwestem side ofthe Nevado del Ruiz (Caldas province). - Paisaje de afloramientos de roca volcánica y arenales en el lado norteoccidental del Nevado del Ruiz (Dpto. de Caldas) a aproximadamente 4350 m con representación de diferentes comunidades vegetales del superpáramo bajo.

Photo 35. Low shrub of Loricaria columbiana associated with bunchgrasses. This is present in the shelter ofvolcanic rock at 4350 m in the lower superpáramo ofthe northwestern slope ofNevado del Ruíz (Caldas province). - Matorral bajo de Loricaria columbiana, asociado con gramíneas en un abrigo de roca volcánica del superpáramo bajo a 4350 m en el flanco norteoccidental del Nevado del Ruiz (Dpto. de Caldas).

La vegetación de páramo

Photo 36. Detail of a branch with biana (Compositae)ofphoto 35.

imbricated xeromorphic leaves and inflorescences of Loricaria colum-

- Detalle de lIna rama con hojas imbricadas xeromórficas e inflorescencias de Loricaria columbiana (Col11positae) de la foto 35. Eastern Cordillera, and the present association fram the Central Cordillera, areCalamagrostis ejjÚsa,lamesoniella rubricaulis, Pernettya prostrata, Racomitrium crispulum, Riccardia spp. and Vacciniumjloribundum. Duque & Rangel (1989) described Lachemillo pectinatae-Loricarietum complanatae fram Puracé Volcano (3800 m) with a rather different floristic composition. A different type of Loricaria columbiana vegetation was observed in contact with the high bunchgrassparamo. This has relatively high cover of Calamagrostis eIJusa and Festuca sublimis. Nevertheless, in the absence of sufficient relevés, it is not described here. Synecology and distribution: The association of Diplostephio eriophori-Loricarietum columbianae reported here, is found on the escarpments of lava frants at the upper Iimit of the superparamo blue grasslands, between 4300 and 4450 m and common in the Parque Los Nevados.

Relationship among the paramo syntaxa Table 1 shows the result of a Twinspan ana]ysis (Rill 1979) on the synoptic table including all syntaxa described here. The importance of altitude and humidity as determining factors for explaining the distribution ofthe paramo vegetation types in the study area is immediately apparent. In the first Twinspan analysis the higher cover c]asses (III, IV and V) were given three times the weight of the smaller cover c]asses (1, II, III). In the second Twinspan ana]ysis, no weights were given to the pseudospecies levels. The weighted Twinspan analysis gave a more satisfactory result than the unweighted one, indicating the relative importance ofthe higher cover classes. This final Twinspan table was not reordered further. There is a major division in the tab]e, which separates the superparamo vegetation fram the other vegetation types. Appraximately half of the total number of species are absent fram the superparamo vegetation. The two main superparamo formations were not c]early subdivided. Vegetation types belonging to the higher superparamo interdigitate with the ones be]onging to

The paramo vegetation

the lower superparamo. Species like Agrostis araucana, Altensteinia (Aa) paludosa, Andreaea rupestris, Cerastiumfloccosum, Draba spp., Lupinus alopecuroides, Montia meridensis, Pentacalia gelida, Poa trachyphylla, Senecio canescens, Stereocaulon vesuvianum and Thamnolia vermicularis occur exclusively in the superparamo. On the other hand, Arenaria serpens, Baccharis caespitosa, Bromus lanatus, Elaphoglossum mathewsii, Erigeron chionophilus, Grammitis moniliformis, Hypochaeris sessiliflora and Luzula racemosa are present in the majority of the vegetation types (with the exception of the meadows), but clearly prefer the superparamo environment. A group of species, consisting of Azorella multifida, Cortaderia sericantha, Festuca sublimis, Hypericum laricifolium, Rumex tolimensis, Senecio formosus and Uncinia macrolepis (U. meridensis) are found both in the forests and in the cushion bogs. Another group of species; Baccharis tricuneata, Carex pichinchensis, Conyza uliginosa, Espeletia hartwegiana, Lachemilla galioides, Ranunculus peruvianus and Satureja nubigena are shared by vegetation types belonging to the cushion bogs, the bunchgrasslands and the meadows. Castilleja fissifolia, Lachemilla holosericea, 1. tanacetifolia, Pentacalia vernicosa and Ranunculus praemorsus a\though present in few vegetation types of the superparamo, mainly belong to the dwarf forests, the bunchgrasslands and the cushion bogs. Apart from a11the trees, some other species like Bomarea linifolia, Calceolaria pentlandii, Geranium cucullatifolium, Hydrocotyle gunnerifolia, Lappula echinata, Oxalis spp., Peperomia hartwegiana, Rubus sp., Stellaria cuspidata and Urtica ballotaefolia are exclusive to the dwarfforests. Distichia muscoides, Floscaldasia hypsophila, Geranium confertum, Myrteola oxycoccoides, Oritrophium limnophilum and Ourisia muscosa are exclusive to the cushion bogs. The meadows form almost a completely isolated group, showing only a weak relation with the bunchgrasslands. Species like Acaena cylindristachya, Bromus unioloides, Elytrigia repens, Plantago linearis and Salvia sp. mainly belong to the meadows. On the other hand, the bunchgrasslands show hardly any exclusive species.

Altitudinal zonation of the paramo vegetation In order to depict the altitudinal zonation ofthe paramo vegetation in the Ruiz-Tolima volcanic massif the longest altitudinal sequences available were chosen. These were located along the east and west sides, respective1y of the Santa Isabel and the Santa Rosa volcanoes, lake OtÚn lake fa11ingin between these two volcanoes. These sequences comprised thirty- four relevés along the Parque Los Nevados transect (TPN relevé s), and a number of relevés made by the first author together with E.H. and C. Kloosterman (SS relevé s) and by the second author (AMe relevés). The structural configuration ofparamo vegetation at the a11iance level ofthe Parque Los Nevados is represented in Fig. 16. On the west slope of the Santa Rosa volcano, the most complete sequence of the zonal vegetation is present. The most extended paramo proper bunchgrasslands belong to the association of Calandrinio acaulis-Calamagrostietum rectae. The spatial distribution of this type of vegetation is not symmetric since it occurs at somewhat higher altitudes, at the outer slopes of both volcanoes. The upper limit ofthe paramo proper bunchgrasslands, belonging to the associationCalamagrostietum effuso-rectae, is found at a higher altitude on the eastern slope of the Santa Rosa volcano compared to the distribution on the western slope. On the west side of the Santa Isabel volcano these bunchgrasslands, together with those of the association Espeletio hartwegianae-Calamagrostietum effusae, are restricted to a sma11 belt. Bunchgrasslands belonging to the association Festuco dolichophyllae-Calamagrostietum ejJÚsae dominate this area. The altitudinallimit between the higher and lower superparamo is diffuse. Above 4400 m the vegetation of the associations Senecioni canescentis-Cerastietum floccosi and Senecioni canescentis-Calamagrostietum ligulatae are present. Both associations belong to the subnival vegetation of the upper superparamo. Sometimes they occur together at the same altitude with or

La vegetación de páramo

Senecio-Ceraslion

f1occosi

(4320-4650

Cerastio-Calamagrostion (3900-4400 m)

rectae

o 50

% cobertura caver

100

Festuco-Agroslion (4220-4470

araucanae m)

Festuco-Calamagrostion (3850-4250

100

% cobertura caver

effusae

o 50

Leyenda

100 % cobertura caver

100

% cobertura caver

legend

caulirósulas

- stem roseNes

lIIIlll

arbustillos

[SS3

macollas

de 40 cm -

herbs 0140 cm

macollas

de 20 cm -

herbs 0120 cm

+ hierbas de 50 cm - shrublets + herbs 0150 cm

rasante

de briófitas

rasante

de líquenes

bryophyte layer

lichen layer

Fig.16. Comparative diagrams ofthe height (m) and cover (%) ofthe different layers ofzonal superparamo (left side) and grassparamo (right side) vegetation types (medium values at the alliance level) in the Parque Los Nevados, Central Cordillera, Tolima and Risaralda provinces. - Diagramas comparativos de tamaño (m) y cobertura (%) de los estratos diferentes de la vegetación zonal del superpáramo (lado izquierda) y páramo prop. dicho (lado derecho) con valores promedios a nivel de alianza en el Parque Los Nevados, Cordillera Central, Dptos. del Tolima y de Risaralda.

even at lower altitudes than the blue grasslands of the lower superparamo, according to local climatic and edaphic conditions. The shrubs of Diplostephio eriophori-Loricarietum columbianae are found in a vast area on the west slope of the Santa Isabel volcano (between 4470 and 4350 m), whereas they occupy only in a small range on both sides of the Santa Rosa volcano. The upper forest limit is situated around 3800 m on the external slopes ofboth the Santa Isabel and the Santa Rosa volcanoes. The internal slopes end at an altitude of 3900 m at lake Otún. Patches of Aciachne acicularis-Escallonia myrtilloides dwarf forests are present in the open paramo near the margins of the Otún lake.

The paramo vegetation

From the azonal vegetation types, the association of Gentianello dasyanthae-Plantaginetum rigidae is by far the most extended type of cushion bogo It is encountered between 3700 and 4200 m on the eastern slope of the Santa Isabel Volcano, and from 4100 to 4200 m on the eastern slope of the Santa Rosa volcano. The cushion bogs belonging to the association Floscaldasio hypsophilae-Distichietum muscoides, have a more restricted distribution and are found mainly around 4150 m on the western slope of the Santa Rosa volcano and around 4350 m on the eastern slope of the Santa Isabel volcano, near the transition with the superparamo. Small patches of cushion bogs belonging to the association Wernerietum humilis are found on the western slope of the Santa Isabel volcano at an altitude of around 4200 m. Those of the association Carici peucophilae-Wernerietum crassae were recorded at about 3800 m on the eastern slope of the Santa Isabel volcano (AMC 625, 637). Dwarfforests ofthe association Gynoxyo-Polylepidetum sericeae are recorded in relevé AMC 623 (4300 m) on the western slope of the Santa Isabel volcano. However, they are also present elsewhere. Between 3830 and 3850 m scrubs belonging to the association Baccharido tricuneatae-Hypericetum laricifolii are recorded in relevés AMC 621 (western slope ofthe Santa Isabel volcano), AMC 635 and AMC 636 on the eastern slope of the Santa Isabel volcano (3830 to 3900 m). The greyish scrubs ofthe association Pentacalietum vernicosi are found in relevés SS 110 and SS 111 (both at 4340 m) on the western slope ofthe Santa Isabel volcano and in relevés SS 123 and SS 124 (4350 m) on the eastern slope of the Santa Isabel volcano. Azonal meadows belonging to the association Muhlenbergietum cleefii are recorded in only one relevé at the western margin of lake Otún, around 4000 m in relevé AMC 60 l. Prickly cushiongrass of Aciachnetum acicularis subassociation lupinetosum microphylli on the eastern slope ofthe Santa Rosa volcano is recorded in relevés SS 44 (4050 m) SS 51 (4030 m) and SS 52 (4070 m). The highest vegetation types on the western slope of the Santa Isabel volcano belong to two different associations of the subnival vegetation types of the upper superparamo. The first is recorded in TPN 2 (4540 m) and belongs to the association Senecioni canescentis-Cerastietum jloccosi. It is replaced at lower altitudes by the association Senecioni latiflori-Calamagrostietum ligulatae, recorded in re1evés SS 106, SS 107 and SS 118 (al! three at 4400 m). Around 4450 m, in TPN 3, the low scrubs of Diplostephio eriophori-Loricarietum columbianae, be10nging to the blue grasslands of the lower superparamo, is found. Between 4400 and 4350 m another association belonging to the lower superparamo blue grasslands; Lupino alopecuroides-Agrostietum araucanae, is recorded in relevés SS 108, SS 109, SS 112, SS 117, SS 119, SS 120, SS 121 and SS 125 between 4350 and 4470 m. The transition to the paramo proper is located at around 4400 m. The first relevé with a paramo proper vegetation is TPN 4 at 4350 m; this comprises a bunchgrassland belonging to the association Calandrinio acaulis-Calamagrostietum rectae var. of Espeletia hartwegiana. The same vegetation type is present in TPN 5 (at 4250 m) and TPN 6 (at 4150 m). Bunchgrassland of Calandrinio acaulis-Calamagrostietum rectae varo typicum is recorded at 4200 m in relevé SS 80. Bunchgrasslands belonging to the association of Festuco dolichophyllae-Calamagrostietum effusae are found in relevé SS 85 at 4140 m. On the eastern side of the Santa Isabel volcano, the highest vegetation type belongs to the association Lupino alopecuroides-Agrostietum araucanae (recorded in TPN 28 at an altitude of 4475 m). The same vegetation type is present in TPN 29 (4400 m). The transition to the bunchgrassparamo is situated at 4360 m. The bunchgrassland of Calandrinio acaulis-Calamagrostietum rectae var. of Espeletia hartwegiana is recorded in three relevés: TPN 30 (at 4315 m), TPN 32 and 33 (both at 4125 m). In between these three relevés, TPN 31 (at 4200 m) records a bunchgrassland belonging to the association Calamagrostietum effuso-rectae. TPN 34 (at 4015 m) represents the association Espeletio hartwegianae-Calamagrostietum effusae. In TPN 26 (at 3900 m) bunchgrassland of Calamagrostietum effuso-rectae is again present. The forest limit on the eastern slope ofthe Santa Isabel volcano is situated around 3800 m. In TPN 27 (at 3750 m) a high Andean forest was recorded.

La vegetación de páramo

The highest relevé on the westem side of the Santa Rosa volcano is TPN 8 at 4550 m; it belongs to the association Lupino alopecuroides-Agrostietum araucanae. From 4460 m, in TPN II to 4390 m, in SS 38, blue grasslands belonging to the association Diplostephio eriophoriLoricarietum columbianae are present. The transition to the paramo proper is located around 4400 m and the first association of the paramo proper bunchgrasslands is recorded in TPN 9 at 4330 m. It belongs to the bunchgrassland of Calandrinio acaulis-Calamagrostietum rectae var. of Espeletia hartwegiana. The same vegetation type is present in TPN 12 at 4250 m. In TPN 10 (at 4175 m) and in TPN 15 (4050 m) the association Calamagrostietum effuso-rectae is recorded. The bunchgrassland of Festuco dolichophyllae-Calamagrostietum eJJÚsae is present in TPN 14 (3960 m) and TPN 16 (3850 m). The forest limit is located around 3800 m; the first high Andean forest is recorded in TPN 17 (at 3755 m). On the eastem slope of the Santa Rosa volcano the highest occurring vegetation type is recorded in relevé SS 40 at 4400 m. It belongs to the association of Senecioni canescentis-Cerastietwn floccosi, in the higher superparamo. In TPN 22 (4425 m) the association Lupino alopecuroides-Agrostietum araucanae of the lower superparamo is found. Another relevé (AMC 605 at 4460 m) also has a vegetation type belonging to that association, while in the relevés SS 38 (4390 m) and AMC 606 (4400 m) low scrub of Diplostephio eriophori-Loricarietum columbianae is present. The transition to the paramo proper is situated around 4400 m. The first bunchgrasslands are recorded in TPN 23 (4400 m), TPN 24 (4300 m), TPN 25 (4200 m), SS 41 (4400 m) and SS 42 (4400 m). All of these records belong to Calandrinio acaulis-Calamagrostietum rectae val'. Espeletia hartwegiana. A dwarfforest of Aciachne acicularis-Escallonia myrtilloides is present in TPN I (3975 m) and TPN 7 (3930 m) at the west margin of lake Otún.

Acknowledgements

Theauthorsacknowledge the support ofDrs. Roberto Jaramillo Mejía and Santiago Díaz Píedrahita for collectionand identification of paramo plant species. We are grateful to profesora Eugenia Brieva for the fine linedrawingsbased on the field sketches of the second author and to Guido van Reenen for the final arrangementof these drawings.

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La vegetación de páramo

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Post Scriptum Ihis manuscript has been finished mid 200 l. The third edition of the International Code of Phytosociological Nomenclature (J. Veg. Sc. 11: 739-768.2000) has not been applied. In volume VII we wil! publish an overview of al! used syntaxonomical names and their formal corrections following the third edition of the Codeo

Synoptic table show the relationship among the different paramo syntaxa.

Tabla sin贸ptica que muestra las relaciones entre los diferentes sintaxa del p谩ramo

Paramo dwarf forests and shrubs. Constancy table indicating the floristic composition and the structure.

Bosques enanon de páramo y matorrales. Tabla de constancia indicando la composición florística y la estructura.

Bunchgrasslands. Constancy table indicating the floristic composition and structure.

Pajonales. Tabla de constancia indicando la composici贸n flor铆stica y la estructura.

Cushion bogs. Constancy table indicating the floristic composition and structure.

Turberas de cojines. Tabla de constancia indicando la composici贸n flor铆stica y la estructura.

Subnival vegetation. Constancy table indicatine the floristic composition and structure.

Vegetaci贸n subnival. Tabla de constancia indicando la composici贸n flor铆stica y la estructura.