M Sc Dissertation(WII)
Permanent URI for this collectionhttp://192.168.202.180:4000/handle/123456789/3
Browse
3 results
Search Results
Item Patterns of Bird Community Structure in Relation to Land-Use Driven Habitat Changes in the Arid Grasslands of Thar Desert(Wildlife Institute of India, Dehradun, 2019) Kher, Varun; Dutta, Sutirtha; Uniyal, V.P.; Page, Navendu V.The Indian Thar desert has seen a massive loss of grassland habitat in the last few decades. The main driver of this habitat loss has been the large-scale change in landuse from pastoralism to agriculture, leading to expansion of cultivated land over grasslands. This expansion, further compounded by a simultaneous rise in livestock population has drastically increased grazing pressure on the remaining rangelands. To complicate things further, irrigation schemes (notably the Indira Gandhi Canal) have led to intensification of agriculture in many areas. Protected area network in this landscape is minimal and ineffective, making the multiple-use agro-pastoral landscapes very important for conservation of wildlife. The largest protected area in the landscape – the “DNP WLS” – is also a multiple-use landscape and home to more than 50k people whose livelihood is tied to the federal mandate of conservation in the sanctuary. 1. Understanding the impact of land use change on native biodiversity is thus very important for conservation of biodiversity in this critical habitat. In this context, my study tries to find effects of land-use change on community structure of birds in the arid grassland of Jaisalmer district in the Thar Desert. 2. Understanding ecology or distribution and abundance of species is incomplete without holistically understanding the patterns and processes occurring at the community level. To this end, I explored the patterns of bird community structure in the Thar Desert and tried to understand how these properties change with land-use driven habitat change, by comparing fundamental properties of biological communities like species richness, abundance and composition. Additionally, I tried to find out potential habitat correlates of these properties, so as to shed some light on the processes that might be driving community assembly in response to land-use change. 3. Bird community structure: My results indicate that local-scale species richness,abundance and composition did not differ significantly between protected grasslands, rangelands and extensive rain-fed croplands, during either of the seasons. However, intensive irrigated croplands had a notably different community structure with higher species richness and abundance, during both winter and summer. The change is community structure of intensive croplands was influenced by the change in native species along with ingression of newly colonised species. Most of the newly colonised species were restricted to areas with intensive agriculture where their survival was potentially facilitated by the new microhabitats created by irrigation and associated changes (Rahmani & Soni, 1997). 4. Regional species pool: Intensive agriculture increased the overall species of birds in the region by sustaining newly colonised bird species; while the number of native species in this pool was only marginally lower than protected grasslands and comparable to all the other land-uses in both the seasons. Considering both the seasons together, protected grasslands had the highest naïve and estimated number of native species while the naïve and estimated number of native species in other three land-uses – Rangelands, extensive croplands and intensive croplands – was only marginally lower. This signifies that most species found in the region can use the entire gradient of land-use types at their current levels of intensification. Although this result by itself does not indicate that, all land-use types can sustain all the native species. 5. Seasonality of patterns: In winter, protected grasslands, rangelands and extensive croplands had similar bird communities, which together were significantly different from the communities in intensive croplands. The same pattern repeated in summer, but the magnitude of difference between bird communities in intensive agriculture and other land-uses was much lower. This pattern was correlated to the pattern shown by vegetation structure of intensive agriculture, which also became more similar to other land-uses after harvesting of crops in the summer. This potentially suggests that bird communities are influenced by vegetation structure and areas with similar vegetation structure would have similar bird communities. 6. Habitat correlates of species richness and bird community composition: In both the seasons, species richness was positively associated with the foliar volume of woody vegetation and negatively associated with forb volume (which in turn was negatively correlated with grass volume). During winter, species richness was positively related to crop volume and during summer, with compositional diversity of vegetation. Community composition like richness was influenced significantly by woody plant foliar biomass in both the seasons. Crop volume also had a significant influence on bird communities during both winter and summer, whereas grass volume was significantly influential only in winters. Conservation implications: This study corroborates many others in indicating that low-impact land-uses are important secondary habitats for conservation of grassland species (Dutta & Jhala, 2014; Wright, Lake, & Dolman, 2012). The inferences further support the commonly advocated approach of conserving grasslands at a landscape scale by strategically placing them as mosaics of low-impact agro pastoral land-use with small protected areas embedded within them (Dutta & Jhala, 2014; Dutta, Rahmani, & Jhala, 2011; Singh et al., 2006).Item Effect of Habitat Structure on Odonate Species Richness in Streams of Kalakkand Mundanthurai Tiger Reserve in Tamil Nadu India(Wildlife Institute of India, Dehradun, 2013) Anilitty, A.S.; Uniyal, V.P.; Johnson, J.A.This study aimed at the responses of species richness of Odonates toward the habitat structure in Kalakkad Mundanthurai Tiger Reserve(KMTR) in Tamil Nadu, India. KMTR lies between latitudes 8° 25' to 8° 53' N and longitudes 77°10' to 77° 35' E with altitude ranging from 50 meters to 1868 meters. Intensive study areas were confined to three beats in Mundanthurai and Kalakkad ranges of KMTR namely Kodamadi, Kannikatti and Sengaltheri. We sampled vegetation and stream structural parameters along with altitude and time of sampling from three drainages, River Thamiraparni, River Servalar and River Kil Manimuthar. Only the second, third and fourth order streams were sampled. Thirty six belt transects were laid and each transect was walked trice. A total of thirty six species were found during the study period. Species richness was calculated using Software· Estimate S version 0.8 and used to do GLM(Generalized Linear Model) in Software R version 3.0.1. Altitude was found to be the most influencing factor on species richness. A second GLM was carried out for the altitude wise stratified data incorporating temporal replicates for each transect. Tree height and stream width were found to be the most influencing factors in this model with p values 0.00007 and 0.001 respectively.Item The Impact of Land Use Change on Litter Beetle and Ant Communities a Coffee-Dominated Landscape in Chickmagalur District, Karnataka(Wildlife Institute of India, Dehradun, 2001) Badrinarayan, Smitha; Krishnamurthy, Jagdish; Uniyal, V.P.Human-modified habitats dominate the landscape on earth. There is an urgent need for investigations into the diversity of biota supported by different land use systems that replace forests. The plantation of coffee is one such land use that occurs in large tracts of the Western Ghats in Karnataka. An observational study on changes in litter faunal communities caused by conversion 'of forests to coffee was attempted at the Koppa and Narasimharajapura taluks of Chickmagalur district. Four replicate blocks containing three treatments: forest, polyculture shade coffee plantations and mono culture shade coffee plantations, were selected using detailed spatial information that existed for this area. These included a land cover map, aerial photographs and topographic sheets. The information from these sources was used to obtain a list of possible study sites, the suitability of which were assessed on the basis of field visits and interviews of the locals. Litter beetle and ant communities were sampled using pitfall traps along two transects within each of the treatments. Measurements of microclimate, vegetation structure and litter parameters were made along with sampling for litter fauna. The organisms obtained in the pitfall :traps were sorted out and the ants and beetles occurring in it were identified to the level of morphospecies. Comparisons of the diversity of beetle and ant morpho species in the forest and two coffee shade treatments were made on the basis of the occurrence and abundance of different morphospecies. Cluster analyses of the twelve sites were done based on the distances between the communities found in them. Patterns revealed using exploratory data analyses were tested using quantitative statistical sampling. There were significant differences in microhabitat structure between the three treatments. Forests were found to be more humid and had more equitable conditions than either of the coffee systems. The beetle and ant communities in the three treatments were also found to be distinctly different. Beetle morphospecies richness and abundance was highest in forests and lowest in the coffee monoculture shade systems. Ants, while having an equal number of morphospecies across the three treatments, were seen to be dominated in abundance by a few species in the coffee mono culture shade systems. Generally, forest sites were seen to cluster together in one group while coffee mono culture shade sites clustered in another. The polyculture shade coffee treatments were seen to be intermediate in their community composition between forests and mono culture shade coffee plantations. The high community turnover rates across the landscape suggest that even remnant forest patches in this coffee dominated landscape need to be protected from further degradation. For further conservation of the litter faunal community, traditional coffee polyculture shade systems need to be promoted to halt conversion to silver oak dominated agricultural systems.