Browsing by Author "Mukherjee, Shomita"

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Annual Report 2009-10
(SACON, 2010) Mukherjee, Shomita; Prusty, B Anjan Kumar; Srinivasan, A
Assessing the distribution and density of the Fishing Cat in Bhitarkanika mangroves of eastern India by
(Wildlife Institute of India, Dehradun, 2024) Ashik, C.S.; Mukherjee, Shomita; Gopi, G.V.; Pandav, Bivash
Identifying the areas of occurrence, population, and the factors affecting the species distribution is critical in conservation and management. The Fishing Cat (Prionailurus viverrinus), a smaller feline native to South and Southeast Asia, is globally vulnerable and adapted to wetland habitats, with a diet primarily consisting of fish. This makes Bhitarkanika, a mangrove ecosystem, an ideal habitat for the Fishing Cat. This study was conducted to estimate the species density, determine the factors affecting its distribution, and assess the effect of lunar illumination and tidal fluctuation on Fishing Cat activity. Despite known occurrences of Fishing Cats in this area, there has been no proper assessment of their population or other ecological studies. Camera traps were deployed in 109 grids, each covering 1km², across a total of 145 km², for 2878 trap nights. Camera trap locations are unbaited, with two cameras used to capture both flanks. Spatially explicit capture-recapture (SECR) was used to estimate the density, resulting in 0.6 ± 0.1 individuals per km². The abundance was also calculated, with an estimate of 99 ± 16 individuals. These density estimates from this study are close to recent high-density estimates for the species. The canopy cover, the width of the creek, canopy cover and the distance to the aquaculture farms significantly influenced the Fishing Cat habitat use, indicating the need for the conservation of natural mangrove habitats and regulation of aquafarms present near the forest. In contrast, the presence of Saltwater Crocodile showed a negative effect on the distribution of Fishing Cats. The Fishing Cats were more active during the brighter nights of the moon phase (μ= 266.783, r= 0.051, p< 0.01) due to better visual detection. The activity was influenced both by the tidal fluctuations in terms of food resources from waterbodies and it is further enhanced by the lunar illumination during the night. Pairwise non-parametric tests showed that the probability distributions of Fishing Cat activity under lunar illumination and tide fluctuation (D= 0.125, p-value = 0.9885 and D= 0.125, p-value= 0.9899) were similar, indicating minimal differences between each probability distribution. This study underscores the importance of protecting the mangrove habitat and controlling aquaculture expansion to ensure Fishing Cat survival in the Bhitarkanika National Park.
Ecological separation of four sympatric carnivores in Keoladeo Ghana National Park, Bharatpur, Rajasthan, India
(Wildlife Institute of India, Dehradun, 1989) Mukherjee, Shomita; Johnsingh, A.J.T.
The study conducted from 5th May 1989 to 9th October 1989 covering summer and monsoon looked at the ecological separation of four sympatric carnivores in Keoladeo National Park, Bharatpur, Rajasthan. The four carnivores were - Jungle cat (Felis chaus), Fishing cat (Felis viverrina), Jackal (Canis aureus) and otter (Dutra perspicillata). Objectives of the study were to determine differences in dietary composition, habitat occupancy and time of activity as well as to tryout methods for studying sympatric lesser carnivores. Five methods were tried out to obtain these Objectives. Line transects and searches during mornings and nights were used to collect data on prey abundance, location of carnivores and their tine of activity. Scats were collected and analyzed to determine dietary composition and see how they differed among jackal, fishing cat and Jungle cat. Otter spraints were not found. The following conclusions are although some amount of overlap is evident an overall difference in habitat use, time of activity and dietary composition is seen. Jackals and Jungle cats are habitat generalists but dietary specialists. "The fishing cat and otter are habitat as well as dietary specialists . Jungle cat and fishhing cat are largely nocturnal Out the Jackal and otter are active throughout the day. Behavioural observations added to the results obtained from the other methods . 100 methods however were found unsuitable for studying lesser carnivores.
Habitat use by sympatric small carnivore in Sariska Tiger Reserve, Rajasthan, India.
(Wildlife Institute of India, Dehradun, 1998) Mukherjee, Shomita; Johnsingh, A.J.T.
The present study on three sympatric carnivores, two felids: jungle cat (Felis chaus), and caracal (Caracal caracal) and one canid, the golden jackal (Canis aureus) aimed at studying their spatio - temporal use of food resources. The hypothesis are as follows : 1) Jungle cat is relatively more eclectic in the kind of habitat it inhabits than the jackal. 2) The felids are mostly nocturnal whereas the jackal is both diurnal and nocturnal ( cathemeral). 3) Diet of the three carnivores differs between seasons. 4) Small mammals «1 kg. body weight) form the major diet of the felids and are taken in proportion to their abundance. 5) Jungle cat and caracal are dietary specialists relative to the jackal. The study was conducted in Sariska Tiger Reserve (STR) which is located between 74° 17' to 76° 34'N and 25° 5' to 27° 33' E. STR encompassing an area of BOO km2 has three core areas of which core 1, with an area of 273.B km2 forms. the proposed National Park. This area functioned as the study site and the intensive study area was approximately 30 km2.
Influence of timber plantations on high-altitude understorey insectivorous birds in the Nilgiris landscape
(SACON, 2020) LAWRENCE, SWAPNA; Mukherjee, Shomita; Robin, V V
The Shola Sky Islands of the Western Ghats have undergone drastic land use changes for over a century due to several anthropogenic activities. One of the main reasons for significant habitat loss and fragmentation in this landscape is the establishment of plantations of many invasive and non-native species such as Acacia spp., Pine spp., and Eucalyptus spp. These are major threats for numerous endemic species that are found in the region including the endangered Nilgiri Sholakili Sholicola major and Nilgiri Laughingthrush Montecincla cachinnans. This study is an attempt at understanding the effects of exotic tree species on high-elevation birds found in the Nilgiris. Under an occupancy framework, I examined the habitat variables that best predict the distribution and abundance of four species of high-elevation understorey insectivorous birds in the Upper Nilgiris Plateau
MOLECULAR PHYLOGENY AND COMPARATIVE BIOGEOGRAPHY OF OWLETS OF INDIA
(SACON, 2019) Koparde, Pankaj Pramod; Mukherjee, Shomita
Geographical ranges of species are a function of the interplay between ecology and evolutionary history. To understand range dynamics of co-distributed species, it is necessary to understand their evolutionary biogeography and ecology. The Endangered Forest Owlet (Heteroglaux blewitti) is a highly range-restricted species and is co-distributed with the widespread Spotted Owlet (Athene brama) and Jungle Owlet (Glaucidium radiatum) in India. The range of Spotted Owlet overlaps with the Eurasian Little Owl (Athene noctua). All four owlets show similar morphology and habits. To understand, processes underlying the nested pattern in the geographical distribution of the co-distributed owls, I used phylogenetic analysis to decipher their evolutionary biogeography, followed by past-projected Climatic Niche Models (CNMs) to understand the responses of the species to paleoclimate with respect to current time. I also modeled the ecological niche of Forest Owlet, incorporating remotely-sensed climate and vegetation data and topography, identified conservation priority areas, and future-projected the niche of Forest Owlet to 2050 to understand future threats to the species. I performed preliminary genetic analysis of a Forest Owlet population sampled from Madhya Pradesh. Results of the phylogenetic analysis showed that H. blewitti is not sister to A. brama, but nested within the Athene clade. H. blewitti, as well as other Athene members, diverged during Plio-Pleistocene boundary (3-5 Ma), possibly as a response to the changing climate. Past-projected CNMs showed that the suitable niche areas for all the owlets underwent cycles of expansion and reduction or a gradual expansion or reduction since the Last Interglacial (~120 Ka), and were nested in climatically stable areas. Forest Owlet niche models (ENMs) constructed using current climate, topography, and vegetation data, which were field-validated, resulted in identifying niche clusters for Forest Owlet in central India. When the ENMs were projected to future climate-change scenarios, reduction and shift in the niche extent were observed, indicating that future climate-change is going to impact the range of Forest Owlet severely. The genetic analysis of Forest Owlet individuals sampled from Madhya Pradesh population revealed low allelic diversity and high sharing of alleles. The results presented here underscore the need for basic research on endangered and co-distributed species to generate information that can aid conservation and form the basis of research recommendations such as deep phylogeny reconstruction, population connectivity and occupancy studies on the species.