Bu onwood

(Conocarpus erectus)

Bu onwood (Figure 29) can be found in the inter dal zone furthest from the sea, in low-salinity, elevated, sandy soils, where it mixes with terrestrial vegeta on. Because of this, some field experts do not consider it a true mangrove.

Bu onwood usually grows as a shrub, although in some cases, provided it receives op mal condi ons, it may grow as a fairly large tree, between 15-23 feet (5-7 m) tall. In Puerto Rico, it usually forms small forests along rocky shores. It may also be found bordering very low-salinity lagoons that are distant from the shore.

Main characteris cs:

Leaves: The bu onwood’s leaves are ellip cal and small (4-9 cm long and 2-3 cm wide). It is the only mangrove tree species with alterna ng leaves. The leaf pe ole is small and, like the white mangrove, has two small salt-excre ng organs on each side (Figure 30a). Like all the other mangrove species men oned, it needs to eliminate salt to maintain proper hydra on.

Flowers: Bu onwood flowers are ny (0.2 cm wide), green and fragrant, and grow in large numbers to form round inflorescences measuring 0.6 -12.5 cm in diameter (Figure 30b).

Fruit: Bu onwood gets its name from the shape of its fruit. The round inflorescences become a brown, round, aggregated fruit, similar to a ny pinecone or bu on. (Figure 30c). Each fruit contains a large number of seeds.

Main disturbances affec ng the mangroves in Puerto Rico

Natural

 Sea level rise - In the best case scenario, it would reduce the inter dal zone which mangroves can colonize; in the worst case scenario, it could submerge and exterminate exis ng mangrove forests.

 Hurricanes and tsunamis - They create strong winds, rainfall events and storm surges which could poten ally tear mangroves from the substrate.

Anthropogenic (caused by humankind)

 Coastal urban development - The increase in human popula on in coastal zones has increased wood clearing (including cu ng down mangrove forests), which increases soil erosion and sediment discharge reaching the sea.

 Mangrove forest clearing - Usually, mangrove forests are cut so that urban development may occur. Their wood is also harvested and used as construc on material for building fish traps, because of the wood’s resilience to water.

 Increased boat traffic on shallow waters - This removes sediments on the bo om (which are usually anoxic; that is to say, without oxygen), and resurfaces the contaminants and toxic substances in the water, to the detriment of water quality and mangrove health, as well as risking the wellbeing of mangrove forest inhabitants.

 Increased presence of nutrients, fer lizers and other contaminants - Discharge from rivers or runoff nega vely affects water quality, hurts mangrove health, and risks the wellbeing of mangrove forest inhabitants.

 Trash - The des bring in trash which gravely affects the many species inhabi ng the mangrove forest.

 Changes in water flow - Altera ons and/or construc on on the coast cause changes in water flow. This changes the water’s characteris cs, such as its temperature or salinity, and can cause widespread ex nc on in the mangrove forest.

Conserva on

In order to preserve these valuable ecosystems, several key issues must be addressed, such as:

 coastal development;

 effec ve management of runoff, used waters and garbage;

 waste reduc on through the use of the three R’s: Reducing the use of disposable materials, Reusing objects as much as possible, and Recycling.

The Department of Natural and Environmental Resources of Puerto Rico (DRNA, by its Spanish acronym) has developed a plan for mangrove protec on and conserva on in Puerto Rico. This plan responds to the public policy established by Law #23, the DRNA Organic Law from June 20, 1972.

There are also a series of federal laws protec ng Puerto Rico’s wetlands. The United States Environmental Protec on Agency (EPA) has a website where any ci zen may anonymously report viola ons to the laws: h p://www.epa.gov/region02/water/wetlands/viola ons.html

Glossary

Aerial prop root - root growing outwards from the main tree trunk in a s lt shape.

Alluvial substrate - deposit of water-transported sediments

Apex - the outer end of a leaf or branch.

Bank mangrove - a type of mangrove that develops in zones adjacent to rivers and lagoons, which have li le water flow and which receive li le influence from the des.

Border mangrove - a type of mangrove which grows along the coast, usually in bays and open lagoons, and exposed to low to moderate waves. This type of mangrove is not associated to freshwater influx.

Cay mangrove - mangroves that develop into islands close to the shore. These mangroves are exposed to low to moderate waves.

Cotyledons - the shape in which the first leaf of a seed-bearing plant embryo appears.

Dormant forest - group of small mangrove trees inhabi ng the shaded undergrowth areas of the main forest, among its roots. They grow quickly when sunlight and spa al condi ons become op mal, such as when older trees die off because of strong winds or hurricanes.

Dorsal surface - top or superior surface of a plant’s leaf.

Estuary - habitat in which seawater becomes diluted as it mixes with freshwater draining from the mainland.

Inflorescence - array or group of flowers at the end of a plant’s stalk or a tree’s branch.

Len cels - projec ons from the tree’s trunk and root surfaces, having a pore to aid in gas exchange.

Li oral zone (inter dal zone) - coastal area under the direct influence of the rising or subsiding des.

Mangrove - tree or shrub with special adapta ons which allow it to thrive in high salinity and poorly oxygenated condi ons.

Mangrove forest - habitat chiefly comprised of mangrove trees; they grow in the inter dal zone, in the space between the sea and the land.

Osmosis - movement of water molecules through a semipermeable membrane, from an area of higher water concentra on to one with less water concentra on.

Pe ole - the leaf’s peduncle, or the stem through which it is a ached to the plant stalk.

Pneumatophore - type of root which grows upwards from the soil. They are a feature of both the black and white mangrove trees.

Primary consumers - Organisms which feed on primary producers (the ones that perform photosynthesis).

Primary producers - Organisms which can transform solar energy into ma er through photosynthesis.

Propagule - the mangrove’s viviparous seed, it is a plant in the early stages of development.

Riparian mangrove - it is a type of mangrove which develops in zones under the influence of rivers and water runoff, and are influenced by the des.

Secondary consumers - Organisms which feed on primary consumers.

Sepals - each of the harder, greenish leaves which form the flower’s calyx.

Stamen - the flower’s male reproduc ve organ, containing pollen.

Stoma - small pore-like orifices located on a leaf’s surface; they are in charge of regula ng gas exchange and minimizing water loss.

Tannins - organic substances present in the red mangrove’s vegetal ssue and which provide its characteris c reddish hue; tannins also offer protec on against bacterial decomposi on.

Ventral surface - bo om or inferior surface on a plant’s leaf.

Wetland - area influenced by aqua c systems and terrestrial systems which are frequently flooded or saturated with superficial or subterraneous water for a period of me.

Zona on - mangrove species distribu on perpendicular to the coast.

References:

CONABIO-CONANP. (2009). Mangle blanco (Laguncularia racemosa). Fichas de especies mexicanas. Comisión Nacional para el Conocimiento y Uso de la Biodiversidad y Comisión Nacional de Áreas Naturales Protegidas, México, D.F.

Ecología. Estuarios. Consulted on November 3, 2012. h p://memo.com.co/ecologia/estuario.html

Environmental Protec on Agency (EPA). Wetlands Viola on - Ini al Complaint Form. Consulted on November 3, 2012. h p://epa.gov/region02/water/wetlands/viola ons.html

Feller, I.C. y Sitnik, M. (1996). Mangrove Ecology: A manual for a Field Course. Smithsonian Ins tu on. Washington, DC.

González Lagoa, J.G. y González Toro, C. (2010). Encuentro con el mar. Puerto Rico: Programa Sea Grant.

Li le, E. y Wadsworth, F.H. (1995). Common Trees of Puerto Rico and the Virgin Islands. U.S. Department of Agriculture - Forest Service.

Mcleod, E. & Salm, R. V. (2006). Managing mangroves for resilience to climate change. Gland, Switzerland: The World Conserva on Union (IUCN).

Muñoz-Hincapié, M. (2007). Manual del Botero y Charlas Ecológicas. Puerto Rico: Departamento de Ciencias Marinas. Universidad de Puerto Rico, Recinto universitarios de Mayagüez.

Ramírez Mella, J. Los manglares: ¿Existe un plan de manejo para los manglares? Consulted on November 3, 2012. h p://cremc.ponce.inter.edu/manglares/manejo.htm

Universidad Pública de Navarra. Iden ficación de plántulas con claves dicotómicas. Consulted on November 3, 2012. h p://www.unavarra.es/servicio/herbario/htm/plantula_BAMH_01.htm