Landscape Heterogeneity: Avifaunal biodiversity relationship Case of Banni grassland, Kachchh
Vidisha Shah Guided by Dr. Deepa Maheshwari Co guided by Dr. Arun Kumar Roy Mahato Masters of Landscape Architecture Faculty of Architecture
May, 2017
Abstract Landscape is never static, it is dynamic. It transforms through seasons and years. If landscape is variable due to natural processes, the ecosystem faces adaptation, evolution and / or extinction. This process is a major contribution to nature. But, if the landscape transforms due to anthropogenic activities, it causes the imbalance in the ecosystem which is unfavourable to the earth. This may lead to changes in climate, biodiversity, habitat etc. Banni grassland reserve of Kachchh, Gujarat being an important biodiversity area has faced a similar imbalance in the ecology by anthropogenic activities and due to some natural processes. There have been certain changes in Banni grassland ecology after the earthquake of 1819, which is a natural calamity. Post 1960, the anthropogenic activities have taken over the grassland. These changes are more remarkable and rapid than natural changes, and it has major impacts on bird biodiversity. Some imbalances can be balanced and controlled by analysing the issues and by providing the needed framework.
Introduction Banni grassland is the grassland in India located on Northern area of Kachchh district (23°33′N to 69°16′E) of Gujarat state in India. It is the largest natural arid grassland in the Indian subcontinent, which used to be Asia’s largest and richest grassland in early times. The land is dynamic in terms of valuable ecologically and socio-culturally uniqueness. Banni is nearly has area of 2617 sqkms, located between the Greater ran of Kutch and mainland. Banni means “bani hui” land, formed by depositions of sediments of Indus and other rivers, which used to flow from Greater Rann of Kutch many years ago. The land is a belt of arid grassland ecosystem located on the southern edge of Greater rann. The formation of Banni consists of various changes including natural and manmade. The grassland has been converted into heterogeneous landscape by passing through several natural and manmade transformations. This fragile landscape comprises of dual ecosystems: Grassland and wetlands. Due to introduction of exotic species, the woodland ecosystem has generated along with grassland and wetland. The land has distinctive ecosystem because of the water, soil, climate and economy practice amalgamation, which is habitat of various type of flora and fauna including many threatened species also. Due to the low-lying characteristics of the land, Banni transforms into several ephemeral water bodies during monsoon and post monsoon. It easily attracts the migratory birds because of the availability of water, food and climatic condition. The migration of birds is visible since many years.
Need for the study There is transformation of the Banni grassland over the years and which have caused the impacts on the ecology. The changes are due to several issues like overgrazing by cattle, degradation of the grassland, spreading and illegal cutting of invasive Prosopis juliflora, salinity ingress, declination in bird population and
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diversity etc. Therefore, there is a need to understand and analyse these issues in depth to provide the necessary guidelines to upgrade the grassland and the habitat avifauna.
Research question
What are the transformations the land had gone through after 1960? (Natural / man-made) Does this transformation have the impact on the avifauna diversity? Whether these impacts are negative or positive? Is there a need for a management plan or suggestive measures? If yes, what are they?
Aim and Objectives Aim: To understand the transformation of avifauna habitat due to anthropogenic activities post 1960 and suggest a management plan and guidelines for the upgradation of grassland and avifauna habitat at Banni grassland. Objectives:
To study and understand the habitat transformation and changing pattern of avifauna in a heterogeneous landscape, affected by anthropogenic activity, since 1960. To analyse the ecological relationship between avifauna and vegetation types with seasonal changes. To study indicator avifauna species with respect to their habitat, migration, feeding, perching, roosting activity in the region, in reference to the resident, migratory and threatened birds. To provide measures to protect avifauna habitat and grassland.
Methodology
General study of understanding the grasslands of world, India and Gujarat. Literature study based on similar issues with inferences. Introduction to Banni grassland reserve on regional scales with details of evolution, demographics, settlements, people, ecology etc. Study of the natural factors responsible for formation of Banni grasslands. Importance of grasslands, including the nuances relevant to study. Study on current status of Banni with in depth details of impacts. Analysis of impacts. Avifauna and their habitat study of the region by finding and studying the indicator species, their distribution in Banni, habitat, threats to species, and their relationship with vegetation. The mapping of distribution of indicator species and important zones for habitats for these species. Analysis of important bird areas from the maps. Guidelines and measures on the bases on analysis.
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Scope and limitations The scope of the study is to understand Banni grasslands with specific reference to avifauna and their habitat. The limitation of the study is that the analysis will be based on study of indicator species of the grassland in detail.
India
Gujarat
Kachchh
Banni Grassland Reserve
Figure 1 Banni grassland location map
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Overview of Banni grassland Banni is located on the north border of Bhuj taluka and falls within the administrative boundary of Gujarat State Forest Department (GSFD) of Kachchh Circle. It falls under three talukas: Bhuj, Nakhatrana and Bhachau. Banni grassland is 86 kms far from Bhuj and 68 kms from Nakhatrana. Greater rann of Kachchh is on the northern and eastern sides of Banni. The little ran of Banni separates grassland from the Kachchh mainland. Banni grassland has a unique history for the formation of the land and the transformation of the vegetation. This history had occurred because of natural processes and anthropogenic activities. 1819 earthquake is considered as a major reason for formation of Kachchh land and thus Banni land was formed. Gradually the grassland developed with a rich biodiversity. The plains are low alluvial table land with elevation of 3 to10 mt from Greater ran of Kachchh. This does not allow the sea tides to enter into Banni. The land is more or less flat without any gradient, with upliftment of Kachchh mainland, Pachchham, Wagad and Bela around it. Banni being a flat land, all the monsoon streams get empty into Banni plains including five major rivers from Bhuj. Soil of the region is saline. Banni grasslands fall under Dichanthium-Cenchrus-Lasiurus type. The grassland is considered under the mid-successional / subclimax type. The vegetation Banni of grasslands is dominated by grasses, following by few herbs, fewer shrubs and trees. Prosopis cineraria, Acacia leucophloea, Acacia Senegal, Acacia spp., Salvadora persica, Salvadora oleoides, Capparis decidua, Tamarix sp. etc.are trees and shrubs, mainly distributed near settlements. The richness in the vegetation, hydrology and unique climate has resulted the hosting of resident and migratory birds, as the location of Banni passes through the migration route. It is habitat of more than 260 birds including migratory birds, with foraging, roosting, nesting, resting and staging grounds. The grassland also supports high diversity of wildlife in addition to thousands of domestic livestock. Banni has very low population density of 3.6 person/sqkm and the major occupation is cattle rearing and cattle breeding as Banni buffaloes are known for its milk yield capacity. Here the cattle are fed on the rich grasses of Banni with free grazing system. Post 1960, Gujarat State Forest Department did a management intervention of introducing Prosopis juliflora to stop the spread of Rann on the northern fringes of Banni, without evaluating the ecological and associated socio-economic consequences in the future. As the result of this plantation, Prosopis become invasive and dominant species in this area and parts of Gujarat.
Importance of grassland: The grassland is important to all the living organisms in different ways. Ecologically, grassland is important for the growth of grasses, food and habitat for birds and animals. And, economically also it is important for people of Banni.
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Animal husbandry is visible for more than 500 years. This grazing pattern is major key to generate economy. More than 60-70% people depend on animal husbandry. Grassland is habitat for many threatened species and endangered species since many years. Because of the dual ecosystems of grassland and wetland, terrestrial and aquatic birds depend on the vegetation and water. Many grasses growing in Banni have the nutrients which cattle needs during their breeding and milking period.
Current status of Banni: Grassland is facing a major degradation due to several reasons like overgrazing, salinity ingress, damming of rivers, Prosopis invasion, desertification etc. The free grazing system with lack of regulations has increased the cattle population above the carrying capacity of Banni grassland. The imbalance of the carrying capacity and intensive grazing pressure has led grassland to a degradation condition. Severe droughts during 1981-1996 have affected the soil moisture majorly, which directly degrades the land. Banni has been going through desertification because of the rann presence, low vegetation cover, soil texture and high evaporation rate and wind erosion. Salinity also creates a layer on soil which decreases the vegetation cover. Salinity has increased due to dam construction, infrastructure development, existing topography and collection of dung.
Impacts on Banni grassland and its Analysis: Current status of Banni is having a major ecological imbalance and other threats. Livestock population has increased 132% in 2007 from the year 1982. Also, because of the availability of rich grass many maldhaaris migrates to Banni post monsoon with their cattle. This floating population also adds the numbers in livestock. Buffalos of Banni have adapted the climate, intake of salt tolerant plants and Prosopis pods, which directly affects the population of livestock and grazing pressure. This has lead Banni into a fragile ecosystem. Intensive grazing has reduced the major reduction of perennial grasses. Overgrazing has replaced the heavily grazed palatable grass species and its density by resistant and woody unpalatable species. Trampling of cattle has hardened the soil and thus the grass germination rate is less.
The salinity has increased highly to almost 50% of the area, which has lead major reduction in vegetation. High saline soil does not support many grasses and it completely devoid good vegetation cover. Increase in salinity affected area has reduced palatable grass area by 14% and increased salt tolerant grass area by 67%. Salinity has changed the floral composition season wise. Grasses have been replaced by salt tolerant grass and herbs. Also, the Prosopis has started growing
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the high saline areas too and have dominated on other species. Density wise also the flora has changed. Acacias and Salvadora density has been declined due to Prosopis invasion. Prosopis juliflora has dominated the native species because of its growth in saline areas and the captivity to grow in such climate with less requirement of water. Density in moderate to strong saline soil is 970/ha and in low/non saline soil is 2440/ha. The correlative relationship of cattle and Prosopis has added one more reason to the rapid spread of this specie. Intake of Prosopis pods by cattle disperses the seeds via dung. These seeds have a high germination rate when it gets available moisture and fertilizer from dung. The population of livestock is directly associated to invasion. By 1998, more than 31.23% of Banni grassland was taken over by Prosopis juliflora. The future assumption is by 2020, 56.42% grassland will be taken over by this invasive species. Infrastructure plays a major part in the imbalance of ecology. Damming of the rivers has almost completely stopped the freshwater flow to Banni. Thus, the salinity leaching process and nutrient supply is completely stopped from 1,603 km2 catchment area except good rainfall years. Thus salinity has increased. It also has Lack of the freshwater from the river has affected some specie growth and germination, which are salt intolerant plants.
In Banni, there are major road construction happening from Bhuj and Nakhatrana. The purpose of roads is facility to the local people as well as tourism. The road level is 2.5 to 3 mtrs high than the land without culvert provision to maintain the water flow during monsoon. In addition to this, during 1965 India – Pakistan war, Punjabi road was constructed without any punctures to pass the sea water to the east ran. Because of this construction, water logging is happening which leads to salinity increase in the area. In future, there is a proposal by the government of a new national highway from Satalpur to Hajipir via Khadir Island and central Banni (Khavda and dhordo). This road also may be responsible for salinity increase and vehicular movements. According to Sardar Sarovar dam project canal network, a branch canal mainly will pass through the east Banni area, where agriculture has already introduced and many farmers are practicing there. Branch of this canal will have adequate amount of water. Agriculture activity may rise because of the water availability, which will lead the conversion of grassland to agriculture land. All the above factors has played a major role in change in bird biodiversity. Due to all major and minor threats like damming of rivers, increasing salinity, infrastructure development, invasion of Prosopis juliflora, vehicular activity bird biodiversity has disturbed a lot in direct or indirect way. Damming of rivers has increased and ingressed salinity which has caused the change in vegetation cycle. Thus, the migration and distribution of some birds have shifted. Invasion and dominance of Prosopis has major effects on the vegetation on which bird are depending for foraging, roosting and feeding.
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Vehicular activity disturbs the wildlife. There are many reports saying the sightings have been decreased of many birds along road side. Road construction has led to water logging areas near roads, which has become the foraging and feeding grounds for aquatic birds. Introduction of agriculture in e-astern Banni has also lead habitat loss for grassland birds and changed the avifauna composition. Branch canal introduction will affect majorly on bird biodiversity for habitat loss and it also may attract some aquatic species.
Avifauna overview: Banni grassland, having the unique history and heterogeneous landscape, attracts many living organisms. The land is known for birds for years including the hosting of threatened and migratory species. It has diversity of habitats along with changing climatic condition, which provides birds an ideal habitat according to their requirement. The birds of Banni play a huge role in the ecosystem to enhance the richness of the bio diversity, also acts as direct / indirect factors in socio cultural strength. Banni grassland hosts 262 species of birds in which 166 are terrestrial and 96 are aquatic species. Status wise there are 118 resident species are resident, 76 species are resident/short migratory, and the rest of the 68 species are migratory to Banni. According to the IUCN Redlist, 4 critically Endangered (CR), 1 Endangered (EN), 8 Vulnerable (VU), 11 Near Threatened (NT) species are there at Banni. Thus, Banni is rich in terms of avifauna. The migration of birds in Banni is visible for more than 500 years and it is consistence except during some drought years. The grassland attracts birds from the other parts of India as well as the parts of globe during winter. Chhari dhandh wetland is the major landscape grain which has attracted migratory birds consistently because of its heterogeneous landscape. Apart from that, several ephemeral water bodies and emergent vegetation post monsoon are driving factors for migration. Banni grassland has varied type of habitats depending on climate, seasonal changes, soil condition, topography etc. Grassland, wetland, woodland, mudflat, saline areas etc. are types of habitats for birds of Banni.
Study on indicator avifauna species: Five indicator species are chosen on the bases of their status in Banni, IUCN status and their association with other birds. The species are as below: 1. Sociable lapwing (Vanellus gregarious) 2. Common crane (Grus grus) 3. Grey Hypocolius (Hypocolius ampelinus) 4. MacQueen Bustard (Chlamydotis macqueenii) 5. Chestnut bellied Sandgrouse (Pterocles exustus)
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The five indicator species are studied in detail which includes the study on: 1. Global level details Description of bird Behaviour Habitat preference during breeding and after breeding Breeding behaviour and nesting sites Food and feeding pattern Migration Population trend Global threats 2.
Status in Banni grassland Habitat type Distribution locations Foraging and roosting behaviour and areas Food Associated species Migration duration at Banni Disturbances at Banni
3. Location mapping After mapping of locations, the important bird zones are mapped by overlapping the locations maps of indicator species.
Recommendations/protection grassland:
measures
for
avifauna
and
The study of indicator species of the region is an important requirement to understand the habitat requirement and overall threats to avifauna. It is based on information available on several reports, newsletters, books and IUCN records. This study reveals the baseline information of the ecology of avifauna and threats. There are several disturbances occurring in Banni grassland. Banni grassland is under many threats and yet, ecological imbalance adds another dimension to it. Threats to avifauna are: Habitat loss due to:
Degradation of grassland Conversion of grassland into cropland Invasion of Prosopis juliflora Removal of native species Infrastructure: Vidisha Shah
Overgrazing Poaching Human movements Human encroachment Vehicular movements Tourism
Damming of rivers Road construction Page 9 of 11
The study help formulating the management level map and guidelines to protect avifauna and grassland considering above threats and analysis as major base factors. 1. Habitat preferance map: Habitat preference map of five indicator species is categorised under 4 zones: i. ii. iii. iv.
Highly preferred habitat Moderately preferred habitat Least preferred habitat High saline area
2. Habitat suitability map: Prepared by overlapping of avifauna habitat preferences. i. ii. iii. iv. v.
Highly suitable habitat – includes subcategories derived by overlapping of maximum and minimum species habitat. Moderately suitable habitat – includes subcategories derived by overlapping of maximum and minimum species habitat. Less suitable habitat – includes subcategories derived by overlapping of maximum and minimum species habitat. Least suitable habitat Not suitable habitat
3. Identification of zones for management and guidelines: Based on Habitat suitability map, zones are defined for protection and management. These zones are: i. ii. iii.
Core areas Buffer areas Peripheral areas
According to zones, guidelines are prepared with consideration of existing vegetation, waterbodies, settlements and road networks. i. Core areas Core areas have the high suitable areas for habitat of avifauna. Also, it falls under important bird areas and rich biodiversity zone.
Strictly reserved area from maldhaaris No grazing pressure / Rotational grazing practice. Intensive areas to introduce Grassland plots with fencing if necessary No settlements allowed No agriculture practice No roads or any other infrastructure allowed Prosopis removal – phase wise Plantation of native grasses
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ii. Buffer areas Core areas are surrounded by buffer areas, which partially allows the activities in buffer areas. iii.
Villagers allowed for fodder cutting Strictly rotational grazing practice Agriculture practice allowed, no cash crops and without pesticide usage. Existing road condition to be taken care of. Peripheral areas Agriculture allowed Roads should have speed breakers. Settlements can remain as it is.
4. Grassland protection and guidelines:
Rotational grazing Grassland plot development Plantation of palatable grass Removal of Prosopis – phases wise Trenching in saline areas to leach salinity Trenching in rich grass areas – to avoid grazing Environment impact assessment before road construction and branch canal of Narmada Control over anthropogenic activities.
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