Patterns and determinants of mammal species occurrence in India (original) (raw)
Related papers
Biological Conservation, 2011
Large mammals face high risks of anthropogenic extinction owing to their larger body mass and associated life history traits. Recent worldwide mammal declines have highlighted the conservation importance of effective assessments of trends in distribution and abundance of species. Yet reliable data depicting the nature and extent of changes in population parameters is sparse, primarily due to logistical problems in covering large areas and difficulties in obtaining reliable information at large spatial scales, particularly over time. We used key informant surveys to generate detection histories for 18 species of large mammals (body mass > 2 kg) at two points in time (present and 30 years ago) in the Southern subregion of the Western Ghats global biodiversity hotspot. Multiple-season occupancy models were used to assess temporal trends in occupancy, detectability and vital rates of extinction and colonization for each species. Our results show significant declines in distribution for large carnivores, the Asian elephant and endemic ungulates and primates. There is a significant decline in detectability for 16 species, which suggests a decline in their abundance. These patterns of change in distribution and abundance repeat in our assessments of spatial variation in occupancy dynamics between the three contiguous forest complexes and two human-dominated landscapes into which the southern Western Ghats has been fragmented. Extinction rates are highest in the human-dominated landscapes. Declines in abundance for several species suggest the presence of extinction debts, which may soon be repaid with imminent range contractions and subsequent species extinctions unless immediate remedial conservation measures are taken. Detection/non-detection surveys of key informants used in an occupancy modeling framework provide potential for rapid conservation status assessments of multiple species across large spatial scales over time.
Biodiversity and Conservation, 2011
There is a realization that managed forests and other natural areas in the landscape matrix can and must make significant contributions to biodiversity conservation. Often, however, there are no consistent baseline vegetation or wildlife data for assessing the status of biodiversity elements across protected and managed areas for conservation planning, nor is there a rapid and efficient means to acquire those data. We used a unified vegetation classification and simple animal sampling design to describe the patterns of abundance of selected mammals as indicator, or characteristic, species in different vegetation types and protected areas vs. managed forest units in the Terai Conservation Area (TCA) in northern Uttar Pradesh state, India. We quantified the relative abundance of 15 mammals of conservation concern from dung counts in vegetation sampling plots within 122 sample patches in 13 vegetation types and 4 management units. Assemblages of species differed both among vegetation types and among management units. Species assemblages in the two protected areas differed strongly from those in two managed forests. Grasslands in protected areas were the most species diverse among vegetation types and had several indicator species. Protected forests were dominated by chital (Axis axis) and nilgai (Boselaphus tragocamelus) in a second species group. A third species group in open grasslands and savannas in managed forests was characterized by cattle (Bos taurus) and Indian hare (Lepus nigricollis). Protected areas clearly are the core conservation area of the TCA for their relatively high habitat value and species diversity, and their protected status minimizes human disturbance. Impacts of human use are high in managed forests, indicating their compromised value for biodiversity conservation. Our simple assessment methodology gives managers a simple way to assess the status of important mammals across landscape conservation units.
The shrinking ark: patterns of large mammal extinctions in India
Proceedings of the Royal Society B: Biological Sciences, 2010
Mammal extinctions are widespread globally, with South Asian species being most threatened. We examine local extinctions of 25 mammals in India. We use historical records to obtain a set of locations at which each species was known to have been present at some time in the last 200 years. We then use occupancy estimation models to draw inferences about current presence at these same locations based on field observations of local experts. We examine predictions about the influence of key factors such as protected areas, forest cover, elevation, human population density and cultural tolerance on species extinction. For all 25 species, estimated local extinction probabilities (referenced to a 100 year time frame) range between 0.14 and 0.96. Time elapsed since the historical occurrence record was an important determinant of extinction probability for 14 species. Protected areas are positively associated with lower extinction of 18 species, although many species occur outside them. We find evidence that higher proportion of forest cover is associated with lower extinction probabilities for seven species. However, for species that prefer open habitats (which have experienced intensive land-use change), forest cover alone appears insufficient to ensure persistence (the complement of extinction). We find that higher altitude is positively associated with lower extinction for eight species. Human population density is positively associated with extinction of 13 species. We find that 'culturally tolerated' species do exhibit higher persistence. Overall, large-bodied, rare and habitat specialist mammals tend to have higher extinction probabilities.
Current Science, 2012
For proper management of a wildlife reserve, it is essential to get estimates of occurrence, abundance, density and biomass of herbivores that in turn determine the density of carnivores. The Biligiri Rangaswamy Temple Wildlife Sanctuary (BRT WLS) is a critical conservation region as it is a living bridge between the Eastern and the Western Ghats of southern India. We made repeated walks of 795.5 km on 33 random line transects covering a total distance of 93 km in the sanctuary. During these walks, we recorded the sightings of herbivores using rangefinder, compass and GPS. We also surveyed the sanctuary driving a jeep during nights to detect typically nocturnal mammals. We analysed the data using DISTANCE software. We recorded 31 species of herbivores and the density of these species differed among habitats that included evergreen, moist deciduous, dry deciduous and scrub forests. Several nocturnal species, including elusive small cats were sighted. We found that leaving out elephants, the herbivore biomass in BRT WLS was 4,127.82 kg/km 2. This places BRT among some of the herbivore-rich wildlife reserves in the country. We recommend that BRT be notified as a Tiger Reserve.
Oryx
Understanding the distribution of wildlife species and their response to diverse anthropogenic pressures is important for conservation planning and management of wildlife space in human-dominated landscapes. Assessments of anthropogenic impacts on mammals of the Indian Himalayan Region have mostly been limited to locations inside protected areas. We studied the occurrence of mammals in an unexplored landscape, the 7,586 km2 Bhagirathi basin, at an altitude of 500–5,200 m. The basin encompasses wilderness areas of various habitat types and protection status that are exposed to a range of anthropogenic pressures. Camera trapping at 209 locations during October 2015–September 2017 confirmed the occurrence of 39 species of mammals, nine of which are categorized as threatened (four Vulnerable, five Endangered) and four as Near Threatened on the IUCN Red List. We recorded five mammal species that were hitherto undocumented in Uttarakhand State: the argali Ovis ammon, Tibetan sand fox Vulp...
2004
Abstract We assessed the distribution and relative abundance of mammals in two rainforest areas, Brahmagiri-Makut and Sirsi-Honnavara, of the Western Ghats, southern India, from November 2001 to April 2002. Both direct (daytime and night-time wildlife sightings through 'recky'walks) and indirect (wildlife signs and local information) methods were employed. A total of 34–35 species, of which we recorded 31–32, are known from the two areas; 14 are in one of the IUCN Red List threatened categories and six are endemic to India.
2006
Methods To assess the mammal abundance, the existing trails were walked repeatedly both during the day and night. Recently in Sharavathi Valley WS forest department has established the line transect to calculate the herbivore occurrence and abundance as a national program. Since no attempt has been made by any researchers to calculate the density in the rainforests of Western Ghats, we used the same transect lines to estimate the density of mammals.
Check List, 2022
Information on the status and distribution of species within a geographical area is vital for developing effective conservation plans. We conducted camera-trapping (n = 473) to determine diversity, species composition, relative abundance index, sampling effort, and conservation status of mammals in forested habitats of Manas National Park, Assam, India. Camera stations accumulated data over 11,388 trap nights over three sampling years: 2017-2019. Camera-traps recorded 34 mammalian species belonging to seven orders, 15 families, and 29 genera, with 22,738 independent records. Among them, 17 species are globally threatened or 50% of the recorded species. The species accumulation curve reached an asymptote, indicating an adequate sampling design for obtaining a robust inventory of the mammalian community. Despite a history of ethnopolitical conflict, almost all mammals expected to occur in the park were detected. Our study will enable future evaluations of the recovery process in terms of changes in mammal abundance over time.
Folia Oecologica, 2021
Barandabhar Corridor Forest (BCF), the biologically functional corridor, is surrounded by the large human settlements that exploit the corridor where large mammals such as tigers, leopards and their prey such as ungulates, primates, and rhinoceros occur. This study aimed to evaluate major determinants that affect the distribution of large mammals in BCF, Chitwan, Nepal that connects the biologically significant Chitwan National Park with the Mahabharat range. The status and distribution of large mammals along the habitat and disturbance gradients were determined by using 29 line transects (mean length = 4.59 ± 0.38 km) that covered a linear distance of 133.13 km. The chital were the most abundant mammals (density per km2 (D) = 8.9095 ± 1.4570 and encounter rate per km (ER) = 1.49) followed by rhesus monkey (D = 38.896 ± 16.013, ER = 0.28), wild boar (D = 14.814 ± 3.57, ER = 0.62), northern red muntjac (D = 9.6566 ± 2.9514, ER = 0.62) and sambar (D = 5.392 ± 2.319, ER = 0.38). Simila...
POPULATION ESTIMATION OF MAJOR MAMMALS IN THE FORESTS OF KERALA - 2011
ii PREFACE Scientific information on the distribution and abundance of wildlife population is a prerequisite for their management. So far, population estimation of wildlife based on scientific methods has been carried out in Kerala State in 1993, 1997 and 2002, covering the larger and medium sized mammals. In 2005, 2007 and 2010, estimation of elephants alone was carried as part of all India elephant population estimation, following the guidelines of the Directorate of Project Elephant, Ministry of Environment and Forests, Government of India. In addition, estimation of tigers, co-predators, prey and their habitat were also carried out during 2006 and 2010. A comprehensive population estimation of the major mammalian species other than that of tigers and panthers was carried out in 2011 by the Kerala Forests and Wildlife Department after about a decade. The whole programme was implemented after a series of discussions among the officials and scientists and imparting training for field staff including the participating volunteers. The task of wildlife population estimation was quite demanding and the attempts taken by the forest officials and scientists from Periyar Tiger Conservation Foundation to reduce possible errors are highly appreciated. The programme was organized and implemented successfully by the officials of the Kerala Forest Department and Periyar Tiger Conservation Foundation. The team of scientists from Kerala Forest Research Institute closely worked with the Department for identifying and deploying volunteers to various Divisions for taking part in the process. The task of preparation of the report after the statistical analysis of the data is carried out professionally by the competent team of Kerala Forest Research Institute.