- Journal Article2012Methodological, temporal and spatial factors affecting modelled occupancy of resident birds in the perennially cultivated landscape of Uttar Pradesh, IndiaLandscape Ecology 27: 59-71. doi:10.1007/s10980-011-9666-3.
Biodiversity persistence in non-woody tropical farmlands is poorly explored, and multispecies assessments with robust landscape-scale designs are sparse. Modeled species occupancy in agricultural mosaics is affected by multiple factors including survey methods (convenience-based versus systematic), landscape-scale agriculture-related variables, and extent of remnant habitat. Changes in seasonal crops can additionally alter landscape and habitat conditions thereby influencing species occupancy. We investigated how these factors affect modeled occupancy of 56 resident bird species using a landscape-scale multi-season occupancy framework across 24 intensively cultivated and human-dominated districts in Uttar Pradesh state, north India. Convenience-based roadside observations provided considerable differences in occupancy estimates and associations with remnant habitat and intensity of cultivation relative to systematic transect counts, and appeared to bias results to roadside conditions. Modeled occupancy of only open-area species improved with increasing intensity of cultivation, while remnant habitat improved modeled occupancy of scrubland, wetland and woodland species. Strong seasonal differences in occupancy were apparent for most species across all habitat guilds. Further habitat loss will be most detrimental to resident scrubland, wetland and woodland species. Uttar Pradesh’s agricultural landscape has a high conservation value, but will require a landscape-level approach to maintain the observed high species richness. Obtaining ecological information from unexplored landscapes using robust landscape-scale surveys offers substantial advantages to understand factors affecting species occupancy, and is necessary for efficient conservation planning.
- Journal Article2012To eat and not be eaten: modelling resources and safety in multi-species animal groups.PLoS ONE. 7(7): e42071.Download
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Using mixed-species bird flocks as an example, we model the payoffs for two types of species from participating in multi-species animal groups. Salliers feed on mobile prey, are good sentinels and do not affect prey capture rates of gleaners; gleaners feed on prey on substrates and can enhance the prey capture rate of salliers by flushing prey, but are poor sentinels. These functional types are known from various animal taxa that form multi-species associations. We model costs and benefits of joining groups for a wide range of group compositions under varying abundances of two types of prey–prey on substrates and mobile prey. Our model predicts that gleaners and salliers show a conflict of interest in multi-species groups, because gleaners benefit from increasing numbers of salliers in the group, whereas salliers benefit from increasing gleaner numbers. The model also predicts that the limits to size and variability in composition of multi-species groups are driven by the relative abundance of different types of prey, independent of predation pressure. Our model emphasises resources as a primary driver of temporal and spatial group dynamics, rather than reproductive activity or predation per se, which have hitherto been thought to explain patterns of multi-species group formation and cohesion. The qualitative predictions of the model are supported by empirical patterns from both terrestrial and marine multi-species groups, suggesting that similar mechanisms might underlie group dynamics in a range of taxa. The model also makes novel predictions about group dynamics that can be tested using variation across space and time.
- Journal Article2012Conservation of the Asian small-clawed otter (Aonyx cinereus) in human-modified landscapes, Western Ghats, IndiaTropical Conservation Science 5: 67-78.Download
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Conservation in human-modified landscapes is important for riparian animals as their habitats extend linearly beyond adjoining protected areas. We examined occupancy and intensity of habitat use of Asian small-clawed otters in coffee and tea plantations and an adjoining protected area in the Western Ghats. We sampled 66 stream segments of 500 m length, using spraints as an indicator of habitat use. Several variables characterising the stream and shoreline were also measured. Occupancy, corrected for detection of spraints, was >0.75 in all three land use types, indicating widespread use of the riparian ecosystem in human-modified landscapes. Intensity of habitat use, however, was much lower in tea (2.08 spraints/500 m) and coffee (2.42) plantations than in the protected area (3.86). Using GLMs we identified the abundance of potential refuges (such as boulders and fallen trees), which was greater in the protected area, as the major factor influencing intensity of habitat use. Shoreline diversity, which was lowest in the tea plantation, might also be another factor. The retention of much of the riparian vegetation and the presence of forest fragments which provide refuges have led to wide occupancy of the tea and coffee plantations although with less intensive use. Sand mining, fishing and infrequent poaching might be other reasons for the relatively low use of human-modified landscape. This study highlights the need to retain remnant forests and riparian vegetation, and to control some human activities for integrated management of species like the small-clawed otter in both protected areas and adjoining human-modified habitats.
- Journal Article2012Patterns of species participation across multiple mixed-species flock types in a tropical forest in northeastern India.Journal of Natural History. 46(43-44):2749–2762.Download
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We studied mixed-species bird flocks in northeastern India to (a) develop a framework for quantifying species participation in mixed-species flocks, (b) characterize the ecology and behaviour of participant species, and (c) explore mechanisms influencing the coexistence of different mixed-species flock types. To characterize participation in mixed-species flocks, we implement a new method incorporating species abundances, minimizing potential biases in measuring participation arising from differences in the availability of flocking species. There are at least three distinct flock types in the lowland forests of northeastern India; these flock types differ in the body mass and vertical stratum use of participant species. The “core” of mixed-species flocks was composed of a species group that differed much more in their foraging method in comparison with “attendant” species. The exchange of benefits and minimization of interspecific competition might lead to, and maintain, heterogeneity in foraging methods among core species of mixed-species flocks.
- Journal Article2012Trends in extinction and persistence of diurnal primates in Upper Brahmaputra ValleyOryx 46(2): 308-311Download
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The historical deforestation of the Upper Brahmaputra Valley in the Indian state of Assam has resulted in the transformation of its once-contiguous lowland rainforests into many isolated forest fragments that are still rich in species, including primates. We report the recent history and current status of six diurnal primates in one large (2,098 ha) and three small (, 500 ha) fragments of the Upper Brahmaputra Valley. We censused primates in the small fragments during 2002, 2005, 2009, in the large fragment in 2008, and used other published census data to derive population trends. We also used key informant surveys to obtain historical occurrence data for these populations. Our analyses reveal the recent extinction of some populations and the simultaneous long-term persist- ence of others in these fragments over 16 years. Most populations appeared to have declined in the small fragments but primate abundance has increased signific- antly in the largest fragment over the last decade. Addressing the biomass needs of the local human populations, which appears to drive habitat degradation, and better protection of these forests, will be crucial in ensuring the future survival of this diverse and unique primate assemblage in the last rainforest fragments of the human-dominated Upper Brahmaputra Valley.
- Journal Article2011Farmland foods: Black-necked Stork Ephippiorhynchus asiaticus prey items in an agricultural landscapeForktail 27: 98-100
- Journal Article2011Moisture and nutrients determine the distribution and richness of India’s large herbivore species assemblageBasic and Applied Ecology 12(7): 634-642Download
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The goal of this study was to test whether body-mass based foraging principles, guided by plant available moisture (PAM) and plant available nutrients (PAN), could explain large mammalian herbivore species distribution and richness in India. We tested (1) whether the occurrence of larger-bodied herbivore species increases with PAM, but is independent of PAN, (2) whether the occurrence of smaller-bodied herbivore species decreases with PAM, but increases with PAN, and (3) whether herbivore species richness is highest in areas with intermediate PAM and high PAN. We analyzed the distribution and richness of the 16 large (>10 kg) herbivore species found in sub-Himalayan mainland India. Since the distributions of large herbivores in India have been altered by historic human activity, we only used India's largest 76 protected areas as data points, with respect to PAM (log10(rainfall/potential evapotranspiration)), PAN (soil cation exchange capacity), elevation, tree cover, and fire frequency. Using regression and null models to analyze the data, we found positive relations between PAM and the occurrences of the larger-bodied species (elephant and gaur), and negative relations between PAM and the occurrences of smaller-bodied species (chinkara, four-horned antelope and blackbuck). We also found positive relations between the occurrence of the smaller-bodied species and PAN. Large herbivore species richness in India is highest in Kanha and Indravati, areas with high PAN and intermediate PAM. We found that elevation, tree cover and fire frequency were insignificant predictors of herbivore species richness, although elevation and tree cover explained the distribution of a few species. Based on our null model analyses results, we conclude that moisture and soil nutrients are important in determining large herbivore species distribution and richness in sub-Himalayan India.
- Journal Article2011Agricultural intensification, rainfall patterns, and large waterbird breeding success in the extensively cultivated landscape of Uttar Pradesh, IndiaBiological Conservation 144: 3055-3063. doi:10.1016/j.biocon.2011.09.012
In countries with high human populations, using agricultural areas as multifunctional systems to produce food for humans and retain wildlife may be an efficient conservation strategy for many species. Inclusion of natural habitat and species requirements on agricultural landscapes explicitly into planning processes are precluded by lack of information on drivers of species persistence. Climate change is an additional emerging complexity, and adaptation plans for agricultural landscapes are biased towards intensification to secure long-range food production. I examine the conservation potential of an agricultural landscape in two districts of Uttar Pradesh, north India where agricultural intensification and altered rainfall patterns are predicted to occur. I assess stressors affecting breeding success over eight years of two large waterbirds of conservation concern – Sarus Cranes and Black-necked Storks. Both species had high breeding success that improved with total rainfall and more wetlands in breeding territories. Agricultural and township expansions deteriorated territory quality and reduced breeding success. Sarus Crane populations were predicted to decline relatively rapidly if development activities continued to displace breeding pairs. Black-necked Storks appeared resilient over the long-term notwithstanding reduced breeding success in low-rainfall years. Waterbird nesting habitats (wetlands and trees) were retained in Uttar Pradesh as community lands by villages and by state government via legal provisions suggesting the utility of multiple conservation approaches. Incorporating species requirements explicitly, alongside traditional land use practices conducive for habitat conservation, into adaptation planning and conservation policy will be necessary to retain long-term multifunctionality of such agricultural landscapes.
- Journal Article2011Less than wild? Commensal primates and wildlife conservationJournal of Biosciences 36: 749-753
- Journal Article2011Patterns of spatiotemporal change in large mammal distribution and abundance in the southern Western Ghats, IndiaBiological Conservation 144: 1567-1576Download
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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.
- Journal Article2010Genetic Polymorphism in the Serotonin Transporter Promoter Region and Ecological Success in MacaquesBehaviour Genetics, 40: 672-679Download
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A well-characterised sequence length poly- morphism in the serotonin transporter promoter region (5-HTTLPR) influences individual behavioural traits and cognitive abilities in humans and rhesus macaques. Maca- ques have been classified into four continuous grades on the basis of their behavioural attributes, ranging from highly hierarchical and nepotistic species to the most egalitarian and tolerant ones. A comparative study of several species that spanned these grades revealed only rhesus macaques to be polymorphic at the 5-HTTLPR and concluded that the polymorphism was responsible for their despotic and aggressive behaviour (Wendland et al., Behav Genet 36:163–172, 2006). We studied wild populations of three other species and found that the egalitarian and tolerant bonnet and Arunachal macaques are also polymorphic while liontailed macaques, although belonging to the same group, are monomorphic. We thus reject a role for this particular polymorphism in interspecific behavioural vari- ability and show that polymorphic species enjoy greater ecological success possibly due to their higher infraspecific variability in individual behavioural traits.
- Journal Article2010Seeing the elephant in the room: human elephant conflict and the Elephant Task Force reportEconomic and Political Weekly 45(49): 29-31Download
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The report of the Elephant Task Force acknowledges the gravityof human-elephant conflicts,and makes a set of potentially far-reaching and forward-looking suggestions to alleviate them. The spirit of most of them is admirable and positive, but the devil, as always, is in the implementation. Managing conflict is as much about protecting farmers and farmlands from elephants as it is about reducing our footprint on the elephant’s domain. The first of five articles that discuss the Elephant Task Force report.
- Journal Article2010Proposed methods to capture and radio-tag the critically endangered Jerdon's Couser in Andhra Pradesh, India.Telemetry in Wildlife Science, ENVIS Bulletin. WII -Dehradun.Download
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Jeganathan, P., Green, R.E., Rahmani, A.R (2010) Proposed methods to capture and radio-tag the critically endangered Jerdon's Couser in Andhra Pradesh, India (in). Sivakumar, K. and Habib,B. (Eds.) 2010. Telemetry in Wildlife Science, ENVIS Bulletin: Widlife & Protected Areas. Vol. 13 No. 1. Wildlife Institute of India, Dehradun - 248001. India. Pp. 205-210.
- Journal Article2010Asian elephant Elephas maximus habitat use and ranging in fragmented rainforest and plantations in the Anamalai hills, IndiaTropical Conservation Science 3: 143–158
- Journal Article2010Effects of plantations and home-gardens on tropical forest bird communities and mixed-species bird flocks in the southern Western Ghats.Journal of the Bombay Natural History Society 107: 91-108.Download
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Conservation scientists and policy makers are increasingly aware of the role countryside habitats play in supporting tropical fauna in modern landscapes. We studied the value of different land-uses by examining composition of tropical bird communities and mixed-species bird flocks in human-altered landscapes of Thattekad and the Anamalai Hills, situated in two different altitudes, in the southern Western Ghats. Sixteen line transects distributed across tropical rainforests, shade plantations of coffee and cardamom, timber monocultures of teak, tea plantations, and home-gardens were surveyed for bird flocks, vegetation structure, foliage profile, and canopy attributes. Results indicate that tea plantations were extremely altered habitats, supporting few rainforest species and were devoid of mixed-species bird flocks. Teak monocultures had high species density but were less conducive for rainforest species that require a well developed and structurally more complex habitat. While bird species richness varied little across land-uses, there was significant variation in community composition, with some sensitive bird species absent from all altered habitats. Coffee plantations with surviving rainforest fragments and cardamom plantations with more native shade trees that mimicked a forest habitat supported more rainforest bird species both in communities and flocks. Maintenance of these shade plantations and restoration of forest fragments is recommended, while their conversion into a poor, more open habitat (tea, teak) is strongly discouraged for bird conservation in fragmented landscapes.
- Journal Article2010Ensuring the future of the tiger and other large mammals in the southern portion of the Nilgiri Biosphere Reserve, southern IndiaJournal of the Bombay Natural History Society 107: 77-85Download
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The Nilgiri Biosphere Reserve, at the tri-junction of Tamil Nadu, Kerala and Karnataka, constitutes arguably one of the finest conservation landscapes in the global range of the tiger. We surveyed the southern part of this region, as well as the adjoining areas, to assess the status of large mammals both within and outside protected areas. Our field assessments suggest that large mammals are almost exclusively confined to protected areas with the few remaining populations outside under severe threat from habitat degradation and poaching. However, large stretches of contiguous forests still remain. We suggest the extension of the recently notified Mudumalai Tiger Reserve in Tamil Nadu such that connectivity is retained and strengthened with Biligiri Rangaswamy Temple Wildlife Sanctuary of Karnataka to the north-east and with Silent Valley National Park of Kerala to the south. We also provide suggestions on strengthening conservation in this landscape. The involvement of local communities in the establishment of the Siruvani Conservation Reserve in Kerala and Tamil Nadu, and Nilambur Conservation Reserve in Kerala, will bolster the conservation of large mammals in this landscape. With the suggested extension, Mudumalai Tiger Reserve has the potential of becoming arguably the finest habitat for tigers across Asia, given the variations in altitude, topography and climate which produce a diversity of vegetation types and consequently, provide the tiger with an assortment of prey ranging from Nilgiri Tahr in the high altitude montane grasslands to Blackbuck in the low-lying dry deciduous and thorn scrub forests.
- Journal Article2010Commercializing bycatch can push a fishery beyond economic extinctionConservation Letters 3: 277-285Download
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Tropical bottom trawling is among the most destructive fishing practices, catch- ing large quantities of bycatch, which are usually discarded. We used question- naire surveys of trawl fishers to look at changes in catches over the last 30 years (1978–2008) along India’s Coromandel Coast. We show that catches and in- come from target species have declined sharply over the last two decades. Meanwhile, costs of fishing have increased substantially and now almost ex- ceed income from target species. Over the same period, bycatch (which was traditionally discarded) has now become increasingly marketable, being sold for local consumption, and as fish meal to supply the region’s rapidly growing poultry industry. Without this income from bycatch, the fishery would scarcely be economically viable. While such a change in the use of bycatch is good news in terms of reducing waste and improving livelihoods, it is also responsible for pushing the Indian bottom trawl fishery beyond the economic extinction of its target species.
- Journal Article2010Trawling the shorelinesSeminar. September 2010. Nature without Borders: A symposium on innovative approaches to conserving nature and wildlife
Fishing in India has grown exponentially. It is an industry adapting to its own economic impulses, keeping itself afloat – quite literally – by responding to changes in supply and demand, seeking new markets, repackaging its products and by-products to woo these new markets, reinventing itself constantly in order to survive. The upshot of this industrial inventiveness is that a system of production that should have been designated unsustainable years ago, continues to persist at an increasing ecological cost. And since all of this happens beneath the waves, it largely escapes the noisy debates over the vanishing wilds.
In this paper we present a potted history of trawl fishing along the Indian coastline, and trace its ecological and economic fallout to coastal communities, both human and marine. We discuss the factors currently driving the economics of trawling within the Indian scenario, and explore potential directions towards a more meaningful management of this harvest. Our discussion focuses on fishery off the Coromandel coast, since that is the area we are most familiar with, but it is indicative of much of the rest of the Indian coastline.
- Journal Article2010The birds of Namdapha National Park: recent significant records and a checklist of the species.Forktail 26: 108-132.
- Journal Article2010Implications of conserving an ecosystem modifier: Increasing green turtle (Chelonia mydas) densities substantially alters seagrass meadowsBiological Conservation 143: 2730-2738
Ecosystem modifiers have the ability to significantly alter the ecosystem they inhabit sometimes with serious consequences for their own populations. We evaluated the ability of green turtles (Chelonia mydas) to modify seagrass ecosystems by their foraging activity. This study was conducted in a seagrass-dominated lagoon in the Lakshadweep Islands, Indian Ocean, where a stable high-density congregation of green turtles is present. We determined a gradient of turtle density in the lagoon and measured the intensity of turtle herbivory across the gradient. We then measured the impact of increasing grazing on seagrass structural parameters, growth and flowering along this gradient. Our results indicate that turtles substantially change seagrass meadow structure (canopy height, shoot length, width and density), reduce flowering and can potentially even cause changes in the species composition of the meadow. We discuss the implications of these results for seagrass ecosystem function, green turtle movement and human attitudes. When conserving ecosystem modifiers like the green turtle, any management strategy needs to include a detailed knowledge of the roles these species play in the ecosystems they inhabit.