M Sc Dissertation(WII)
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Item Effect of Grazing on the Community Structure and Functional Diversity of Grazing Lawns in Sathyamangalam Tiger Reserve(Wildlife Institute of India, Dehradun, 2021) Malagi, Aaroha; Adhikari, B.S.; Page, Navendu V.; Ramesh, K.Understanding the effects of grazing (by both livestock and wild ungulates) on grasslands is paramount to come up with more robust managerial actions to conserve, and increase the ecosystem function of these valuable ecosystems. In the current study, we investigate the effects of grazing on a highly productive, mesic grassland ecosystem, viz. grazing lawn in Sathyamangalam Tiger Reserve, Tamil Nadu, India. We examined how species richness and composition of a grassland patch change across a grazing gradient by carrying out plot-based vegetation sampling in the grazing lawns of Sathyamangalam Tiger Reserve. We also looked at how trait composition and functional diversity changed across the grazing gradient, to better understand the plant functional response and resilience of the grazing lawn complex. We used a Linear Mixed Effect Model (LMM) to investigate the impact of grazing intensity on species richness, and a Non-metric Multidimensional Scaling (NMDS) to look at the differences in species composition between different grazing treatments. Functional composition and diversity were measured using Lavorel and Villeger’s index in the ‘FD’ package of R (4.0.2). We found that grazing lawns were minimally affected by grazing intensity in terms of species richness and trait composition, but showed a significant change in species composition and functional diversity across the grazing gradient.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 Factors Influencing Small Carnivore Community Structure in Chandoli National Park Northern Western Ghats(Wildlife Institute of India, Dehradun, 2019) Lad, Himanshu C.; Gopi, G.V.The current study was conducted on small carnivores in Chandoli National Park of Sahyadri Tiger Reserve from December 2018 to April 2019. The main objectives was to understand drivers of spatial distribution and temporal variation amongst sympatric small carnivores present in the study area. This study provided information on local small carnivore distribution, dietary pattern of palm civet and time activity patterns of small carnivores in Chandoli national parkItem Responses Shown by Bird Communities to Teak Palatations in Sagar Forest Division, Karnataka(Wildlife Institute of India, Dehradun, 2009) Barve, Sahas S.; Mohan, D.; Qureshi, QamarThis study was aimed at discerning the responses shown by bird communities to teak plantations of various age classes in Sagar Forest Division, Karnataka within Latitude 13° 36' and 14° 38' North 74° Longitude 38' and 75° 32'East Latitude. Birds were sampled using line transects in three habitat strata, natural plantations, mature teak plantations and young teak plantations. Density, diversity and community similarity were the chief ecological responses that were quantified to bring out differences in the usage of forest plantations by native bird fauna. Habitat (vegetation) correlates, both structural and floristic were quantified to establish the reasons for differences. The sampling period was from December 2008 to April 2009. This period was divided into two seasons, winter and summer. A total of 9 transects were laid, marked and sampled at least 4 times per season. Birds were divided into three feeding guilds and three habitat guilds for analysis. The overall density of birds across the three strata was found to be higher in summer than in winter. However a guild level analysis showed that in winter while insectivorous birds were most abundant in natural forest with decreasing density towards young plantations (F (6.241) , p< 0.05). There was no difference in their density in summer. Phytophagous birds showed the exact reverse trend. Density of this guild was higher in young plantations than natural forests and mature plantations in winter and summer (F(S.689), p< 0.05), (F (14.302), p< 0.01) respectively. Overall diversity of birds showed a trend of decreasing species richness from natural forests to young plantations in both seasons. However this difference was almost non existent in summer at the guild level. The abundance of birds belonging to evergreen and moist deciduous forests shows a consistent· rise in abundance from winter to summer in all the three strata. There is also evidence that there is ingression of individuals of species that were common to both seasons possibly for nesting. The overall community similarity is quite high between the three strata and it increases from winter to summer. Bird diversity was found to be affected by the vertical spread of vegetation and tree height heterogeneity (R=0.871, pItem Disturbance and Coral Community Structure in the Intertidal Coral Reefs of the Southern Gulf of Kutch(Wildlife Institute of India, Dehradun, 1995) Arthur, Rohan; Jhala, Y.V.I quantified the coral community structure using quadrat sampling in two intertidal coral reefs off the island of Narrara and Pirotan in the Southern Gulf of Kutch. These areas are subject to heavy disturbance from industries, and anthropogenic pressures on the reef are considerable. Species richness and indices of diversity indicate the reefs are of low diversity. Species diversity values indicate that Narrara has a lower species diversity (H'= 2.822, SE 0.139) than Pirotan (H'= 3.95, SE 0.126) (t-test d.f. = 236, P < 0.00 I). However, environmental data collected from both areas indicate that the levels of disturbance, measured as the mean percentages of dead coral, sediment load on live coral, algae cover and bleaching, was generally higher in Pirotan than in Nanara. Multivariate techniques of analysis were used to elucidate these trends. Community clustering using the statistical package TWINSPAN and direct ordination using Canonical Correspondence (statistical package CANOCO) were carried out. Axis I correlated well with the percentage of boulders in the reef and the density of algae, and Axis 11 correlated well with sediment load on the coral. Species showed clear patterns of distribution along these axes. I set up experiments to test the effect of crude oil and bittern, a salt manufacturing by-product, on two common reef Scleractinidia, Porites compressa and Favia favus. Significant effects were seen with both pollutants. Most of the replicates showed some level of recovery though this recovery did not result in any of the coral regaining total health. Indices of coral sensitivity and coral recovery was developed and this proved a valuable means of comparing the response of different species. Bittern and crude oil stressed the corals and resulted in sediment deposition. The immediate cause of mortality was caused by sediment deposits on the coral boulders. In highly turbid reefs, coral species might be affected more by high sedimentation levels than by other environmental stressorsItem Avian Communities in the Riparian Areas of Bori Wildlife Sanctuary, India(Wildlife Institute of India, Dehradun, 1993) Pai, Ashwini; Johnsingh, A.J.T.Riparian areas are important as special habitats and corridors for wildlife. However, in India, riparian areas have not been studied to any detail. Also, not much is known about the avifauna of riparian habitats. The vegetation near a riparian area tends to be dense and hence distinct owing to constant availability of water. Riparian areas come under heavy use, both by livestock as well as wild animals because of the presence of water and forage. The avifauna of riparian areas is rich due to its floral complexity and structure and resources like fish and insects. This study quantified bird species diversity, avian guilds and avian community structure found in four riparian areas ( a flood plain, a riparian scrub, a disturbed nulla and an undisturbed nulla) of Bori sanctuary in Central India. The riparian areas were compared with the adjoining deciduous forest for avifaunal differences. Vegetation was studies along the riparian areas and the deciduous forests, using circular plots. Tree and shrub densities, vertical stratification of foliage and species richness were quantified. Line transects were used to estimate bird ,species richness and abundance. Bird species richness was correlated to negative variables for the two seasons. In summer the BSR was highly correlated with CC and in winters with CC. Stepwise multiple regression was used to create a habitat model for BSR in summer and in winter. Community patterns show seasonal change and also respond to structural changes of habitat.Item A Study on Bird Communities-Habitat Structure Relationships in Pench National Park, M.P.(Wildlife Institute of India, Dehradun, 1997) Jayapal, R.; Qureshi, QamarThere has been a number of studies on bird communities and their relationships with habitat features of floristics and physiognomy. In particular, the spatial distribution of bird communities along the axis of structural variables of a habitat has received a wider attention in the light of recent findings on landscape behaviour. Most of these works relate to either temperate or neotropical forests and our knowledge of community dynamics of tropical deciduous forests is very limited, for there has been hardly any comprehensive study in the tropics. The present study was done in the deciduous forests of the Pench National Park, Central India (M.P) between "November, 1996 and April, 1997 covering winter (November,1996-1anuary,1997) and summer (March, 1997-April, 1997). Seven distinct habitat types were identified for the study based on floristic and structural diversity. Seasonal data on 27 habitat structural variables were collected from bird-centered sampling plots. Point count census technique was employed to study the bird population. Principal Components Analysis (PCA) was used to determine the patterns of inter-relationships among the habitat structural variables. Canonical Correspondence Analysis (CCA) was done to understand the relationships of habitat components to the distribution of bird communities. For guild analysis, two different sets criteria were used to identify the guilds among the bird populations viz., food type and foraging behaviour. Twelve guilds were recognized based on the food type and, six among the insectivores with respect to foraging behaviour. The results of the PCA showed that habitat structural variables of tropical deciduous forests have a marked pattern of inter-relationships on two axes of landscape behaviour, viz., heterogeneity and complexity. But they failed to reveal any such segregation vis-a-vis bird community structure, as the scale of measurement did not address all the members of the community. The spatial distribution pattern of bird communities in relation to habitat architecture was shown by CCA to be not very tenacious; the interactions of other extraneous factors like floristics, habitat dynamics, phenophases of vegetation, disturbance, or interactions within the community may influence the habitat selection process. There was no linear correlation observed between Foliage Height Diversity and Bird Species Diversity; possible explanations and alternative views have been discussed briefly. The response of bird communities to floristics was found to be inconsistent across habitat types as positive linear relationship was detected only for Teak-dominant forests in winter, and for Anogeiss Boswellia forests and Cleistanthus collinus woodland in summer. Guild compositions of various habitat types were not found to be significanty different from each other though the seasonal change was consistent across all the habitats.Item Shifting Cultivation and Conservation of Tropical Forest Bird Communities in Mizoram, North-East India(Wildlife Institute of India, Dehradun, 1995) Raman, T.R. Shankar; Johnsingh, A.J.T.The impact of the traditional practice of shifting cultivation or jhum on evergreen and semievergreen forest bird communities was studied in Dampa Tiger Reserve in western Mizoram, north-east India. Bird community changes through vegetation succession was studied by comparing sites that were jhum 1,5, 10,25, and 100 years ago with primary forest that has never been cleared. Systematic line transect sampling showed that bird species richness, abundance, and diversity, increased from very low levels in the I-year old fallow to maximum levels in undisturbed and 100-year old forest, with intermediate values in the 5-25 year fallows (bamboo forests). The trend of increase was not linear but hyperbolic, with a rapid increase up to 25 years approaching an asymptote at 100 years . Similarity in bird community composition between two sites was inversely related to the difference in the logarithm of their ages. Trends in bird communities were closely related to changes during vegetation succession. Vegetation variables measured were summarised by Principal Components Analysis, which yielded two components (PCI and PC2), accounting for 91.9% percent of the variance in the data-set. PCI was correlated positively with tree density, woody plant species richness, vertical stratification, depth of leaf litter, and canopy cover, and negatively with horizontal heterogeneity in the vegetation. PC 1 thus represents the changes occurring during woody plant succession. PC2 was correlated strongly with bamboo density, which shows an increase from 1 to at least 25 years after jhuming and declines in mature forest, and this axis was taken to represent bamboo succession . Bird species richness and abundance were positively correlated with PCI (woody plant succession). When the effects of PC I were removed by partial correlation, both variables were negatively correlated with PC2. The number of species in guilds such as frugivores, nectarivore insectivores, bark-feeder, canopy insectivores were positively related to PC 1. Only the bamboo-substrate feeding guild was related to PC2. These results suggest that bird community structure is largely determined by ,woody plant succession. Mature forests were found to be the main habitat for forest specialists, rare birds, and altitudinal migrants. Thirteen specialised open-country birds and two species of latitudinal migrants occurred mainly in jhumed areas. These were generally common and widespread species that will likely persist in highly disturbed areas. In terms of conservation of the forest birds of the region, mature forests are most important. The major implication of the study relates to the observed hyperbolic changes in bird species richness, and vegetation variables such as woody plant species richness. This suggests species loss in jhumed areas will be a logarithmic and not linear function of the age, i.e. a decline in jhum cycle from 100 to 50 years Ca 2-fold difference) will have less impact than a decline from 25 to 5 years Ca 5-fold difference). This implies that under the 5-10 year jhum cycles that are prevalent in most parts of north-east India today, there will be substantial losses in bird species richness. This effect may be accentuated if primary forests are not part of the jhum habitat matrix.Item A Study of Heterospecific Flocking and Nonbreeding Bird Community Structure of Rajaji National Park(Wildlife Institute of India, Dehradun, 1991) Rai, Nitin D.; Johnsingh, A.J.T.Many workers have found a direct relationship between bird community structure and vegetation structure. To investigate this and describe the heterospecific flocking behaviour of nonbreeding birds I sampled five habitat types in the Dholkhand range of Rajaji National Park, U.P., India. Inter-habitat differences in flocking and bird community structure were considered. I used the line transect technique to sample bird communities. Mixed species flocks were observed to investigate why birds flock. The guild structure based on diet and foraging strategy showed a marked difference between habitats. Species richness was estimated using rarefaction analysis, a procedure that standardizes the unequal area of the different sites. I used a correlational approach to answer the question – what determines bird species richness ? Foliage height diversity, canopy cover, canopy height, canopy height difference, tree density, tree species numbers and cross sectional area, were used as the vegetation variables. Results indicate that none of the variables have strong predictive value though tree species number which is the only floristic measure of the habitats has a consistent influence independent of sample size. The guild structures suggest that the bird communities vary with floristic aspects, of the habitats. To test my hypothesis that flocking is a response to food availability I related bird densities, which is an indicator of food availability, to flocking tendencies and found a inverse relationship. I also found behavioural evidence to suggest that flocking is also an anti-predatory strategy.