- Journal Article2013Long-Term occupancy trends in a data-poor dugong population in the Andaman and Nicobar ArchipelagoPLoS One. 8(10): e76181
Prioritizing efforts for conserving rare and threatened species with limited past data and lacking population estimates is predicated on robust assessments of their occupancy rates. This is particularly challenging for elusive, long-lived and wide- ranging marine mammals. In this paper we estimate trends in long-term (over 50 years) occupancy, persistence and extinction of a vulnerable and data-poor dugong (Dugong dugon) population across multiple seagrass meadows in the Andaman and Nicobar archipelago (India). For this we use hierarchical Bayesian dynamic occupancy models accounting for false negatives (detection probability,1), persistence and extinction, to two datasets: a) fragmentary long-term occurrence records from multiple sources (1959–2004, n = 40 locations), and b) systematic detection/non-detection data from current surveys (2010–2012, n = 57). Dugong occupancy across the archipelago declined by 60% (from 0.45 to 0.18) over the last 20 years and present distribution was largely restricted to sheltered bays and channels with seagrass meadows dominated by Halophila and Halodule sp. Dugongs were not found in patchy meadows with low seagrass cover. In general, seagrass habitat availability was not limiting for dugong occupancy, suggesting that anthropogenic factors such as entanglement in gillnets and direct hunting may have led to local extinction of dugongs from locations where extensive seagrass meadows still thrive. Effective management of these remnant dugong populations will require a multi-pronged approach, involving 1) protection of areas where dugongs still persist, 2) monitoring of seagrass habitats that dugongs could recolonize, 3) reducing gillnet use in areas used by dugongs, and 4) engaging with indigenous/settler communities to reduce impacts of hunting.
- Journal Article2013An expedition to Narcondam: observations of marine and terrestrial fauna including the island-endemic hornbill.Current Science 105: 346-360.
- Report2013Hornbill Nest Adoption Program - 2013 Breeding seasonHNAP Report for 2013Download
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2013 Report for Hornbill Nest Adoption Program
- Journal Article2013Phenology, seed dispersal and regeneration patterns of Horsfieldia kingii, a rare wild nutmegTropical Conservation Science, 6 (5): 674-689.Download
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We present observational data on the flowering and fruiting patterns, seed dispersal, seedling recruitment and survival of a dioecious Myristicaceae species, Horsfieldia kingii, that occurs in the tropical forests of Arunachal Pradesh. Horsfieldia is rare (1 tree ha1) with a scattered distribution; Horsfieldia trees did not flower every year, and flowering was staggered from April to July. Peak ripe fruit availability of Horsfieldia is from February to March. Failure of fruiting occurred in most years, and only 0-33% of sampled trees bore ripe fruits. Initiation of hornbill breeding coincides with the ripe fruit availability of this species. The percentage of hornbill nests in which nesting is initiated each year varies from 50 to 100% of nests, and our results show a significant positive relationship between the percentage of hornbill nests that are active in a given year and the contribution of the species to hornbill diet (n = 6 years). However, the overall contribution to the breeding season diet of hornbills is very low because of poor fruit availability in most years, resulting in limited seed dispersal at nests. Recruitment and survival of Horsfieldia seedlings below parent trees and hornbill nest trees were low; however, seedling survival was marginally higher at nest trees, suggesting that dispersal by hornbills even in a spatially contagious manner may be critical for this species. However, current recruitment of Horsfieldia at hornbill nests (2010) is significantly lower than at parent trees. This species appears to be seed-limited, while dispersal limitation may play a secondary role in determining its abundance.
- Popular Article2013Death in the hillsIndian Express, The Sunday Express Magazine
Foot-and-mouth disease (FMD) had made its way into the mountains from the plains of Pasighat in Arunachal Pradesh. The worst affected were the semi-domesticated mithun (Bos frontalis) that were dying out even as their owners watched helplessly. Each day, as one more animal was found dead in the forest or beside the road, another few were seen salivating profusely from the mouth as the infection spread rapidly.
- Journal Article2013Records of small carnivores from in and around Namdapha Tiger Reserve, Arunachal Pradesh, India.Small Carnivore Conservation 49: 1-8.Download
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For most of Northeast India’s diverse assemblage of small carnivores, direct observations and ecological information are limited. Opportunistic direct observations and camera-trap records from 2008 to 2013 in eastern Arunachal Pradesh recorded 11 small carnivore species of the 20 likely to occur. Observations included the first confirmed Small-toothed Palm Civet Arctogalidia trivirgata sighting from India; dietary observations of five species and hunting of two species.
- Journal Article2013Spatial and temporal variation in hornbill densities in Namdapha Tiger Reserve, Arunachal Pradesh, north-east IndiaTropical Conservation Science 6:734-748Download
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Asian hornbill populations are declining across their ranges because of hunting and deforestation. Five of the 32 Asian hornbill species occur in north-east India. However, vital information on their abundance from the region remains scanty. Understanding spatiotemporal variation in densities provides crucial information for formulating effective conservation strategies based on species-specific abundance patterns and population trends. We examined spatiotemporal variation in densities of four hornbill species in the Namdapha Tiger Reserve, a site identified as an important site for hornbill conservation in Asia. We collected data through variable-width line transect sampling (effort=842.1 km) in the non-breeding season from 2009-12 to estimate hornbill densities. We had 458 detections of four hornbill species. We have estimated White-throated Brown Hornbill densities (7.9 birds/km2) for the first time throughout its entire range. The mean Rufous-necked Hornbill densities (6.9 birds/km2) were higher than those reported elsewhere. Great (3.9 birds/km2) and Wreathed Hornbill (16.1 birds/km2) densities were comparable with other sites. The peak densities of all hornbill species in November-December are among the highest reported from Asia. Wreathed Hornbill densities showed temporal variation peaking in November-December (68 birds/km2) and drastically declining by March-April (1.3 birds/km2), indicating seasonal altitudinal movement to low elevation areas outside the reserve during the breeding season. Our results underscored the spatial variation in hornbill distribution, with low densities of Great and the White-throated Brown hornbills in higher elevations. Our study demonstrates the global importance of Namdapha for hornbills, given its large area and high densities of four hornbill species.
- Journal Article2013First record of Tristram's Bunting Emberiza tristrami from IndiaIndian Birds 8:134-135
- Journal Article2013Opportunistic exploitation: an overlooked pathway to extinctionTrends in Ecology and Evolution. 28(7): 409-413Download
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How can species be exploited economically to extinction? Past single-species hypotheses examining the economic plausibility of exploiting rare species have argued that the escalating value of rarity allows extinction to be profitable. We describe an alternative pathway toward extinction in multispecies exploitation systems, termed ‘opportunistic exploitation’. In this mode, highly valued species that are targeted first by fishing, hunting, and logging become rare, but their populations can decline further through opportunistic exploitation while more common but less desirable species are targeted. Effectively, expanding exploitation to more species subsidizes the eventual extinction of valuable species at low densities. Managers need to recognize conditions that permit opportunistic depletion and pass regulations to protect highly desirable species when exploitation can expand to other species.
- Report2013MigrantWatch 2007-2012Unpublished report, Citizen Science Programme, National Centre for Biological Sciences.
- Journal Article2013Can wetlands maintained for human use also help conserve biodiversity? Landscape–scale patterns of bird use of wetlands in an agricultural landscape in north IndiaBiological Conservation 168: 49-56. http://dx.doi.org/10.1016/j.biocon.2013.09.016
Wetlands in tropical agricultural landscapes are maintained largely by local institutions explicitly for human use, which is assumed to deter biodiversity. Conservation efforts have been biased towards protecting large wetlands that are assumed to be adequate to conserve the majority of species of focal taxa, usually birds. These assumptions remain untested, and landscape-scale conservation planning for wetlands is largely absent, as is a generalised understanding of wetland use by focal taxa. We designed a landscape-scale survey to understand patterns and processes determining beta diversity of birds using agricultural wetlands in south-western Uttar Pradesh, India where wetlands have experienced prolonged and intensive human use for several centuries. Observed bird species richness (99 species in 28 wetlands) is the highest known for any agricultural landscape in south Asia signifying that even intensive human use of wetlands does not necessarily deter their ability to retain biodiversity. Birds exhibited strong scale
dependent wetland use underscoring the need to conserve wetlands of varying sizes and at varying densities on the landscape. Beta diversity was due largely to species turnover (0.877) with minimal effect due to nestedness (0.055) suggesting that conserving a few large wetlands will not adequately meet goals of conserving the majority of wetland bird species. Prevailing assumptions regarding biodiversity conservation in tropical agricultural wetlands require being revised, and a landscape-scale approach that incorporates ecological realities is needed. Incorporating local institutions alongside formal protectionist methods offer a potential win–win situation to maximise conservation of biodiversity in tropical agricultural wetlands.
- Journal Article2013Antelope mating strategies facilitate invasion of grasslands by a woody weed.Oikos. 122(10): 1441-1452.Download
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Intra and interspecific variation in frugivore behaviour can have important consequences for seed dispersal outcomes. However, most information comes from among-species comparisons, and within-species variation is relatively poorly understood. We examined how large intraspecific differences in the behaviour of a native disperser, blackbuck antelope Antilope cervicapra, influence dispersal of a woody invasive, Prosopis juliflora, in a grassland ecosystem. Blackbuck disperse P. juliflora seeds through their dung. In lekking blackbuck populations, males defend clustered or dispersed mating territories. Territorial male movement is restricted, and within their territories males defecate on dung-piles. In contrast, mixed-sex herds range over large areas and do not create dung-piles. We expected territorial males to shape seed dispersal patterns, and seed deposition and seedling recruitment to be spatially localized. Territorial males had a disproportionately large influence on seed dispersal. Adult males removed twice as much fruit as females, and seed arrival was disproportionately high on territories. Also, because lek-territories are clustered, seed arrival was spatially highly concentrated. Seedling recruitment was also substantially higher on territories compared with random sites, indicating that the local concentration of seeds created by territorial males continued into high local recruitment of seedlings. Territorial male behaviour may, thus, result in a distinct spatial pattern of invasion of grasslands by the woody P. juliflora. An ex situ experiment showed no beneficial effect of dung and a negative effect of light on seed germination. We conclude that large intraspecific behavioural differences within frugivore populations can result in significant variation in their effectiveness as seed dispersers. Mating strategies in a disperser could shape seed dispersal, seedling recruitment and potentially plant distribution patterns. These mating strategies may aid in the spread of invasives, such as P. juliflora, which could, in turn, negatively influence the behaviour and ecology of native dispersers.
- Journal Article2013People, predators and perceptions: patterns of livestock depredation by snow leopards and wolves.Journal of Applied Ecology 50 (3), 550-560
- Journal Article2013Understanding the patchy distribution of four-horned antelope Tetracerus quadricornis in a tropical dry deciduous forest in Central IndiaJournal of Tropical Ecology, 1-10. doi:10.1017/S0266467413000722
At the landscape level, the four-horned antelope is confined to tropical dry deciduous forests and within these, their distribution is patchy. Various factors have been proposed as determinants for their patchy distribution within landscapes, but none provided an adequate explanation. We hypothesized that availability of a constant supply of forage influenced the species distribution.We found that the four-horned antelope mainly fed on fruits and flowers, and that a total of 60% of the tree species in Panna Tiger Reserve bore fruits at different times of the year. High tree species richness in habitat patches was considered a surrogate for constant supply of forage for the four-horned antelope. Data from 547 sighting locations between 2002 and 2006 and six spatial layers were analysed using maximum entropy to produce a probability distribution model for the four-horned antelope in Panna Tiger Reserve. Our model predicted that habitat patches summing up to only 9.5% of the 543 km2 of Panna Tiger Reserve had high probability of distribution (>0.5) of four-horned antelope. Although all variables contributed to the distribution model of the four-horned antelope, explanatory power was highest for tree species richness within habitat patches. The distribution of four-horned antelope within tropical dry deciduous forests can be treated as an indicator of high tree diversity and hence habitat quality.
- Book Chapter2013Goral Nemorhaedus goralMammals of South Asia (eds A. J. T. Johnsingh & N.Manjrekar).Universities Press, Hyderabad.
- Journal Article2013Design and Evaluation of a Robust Optical Beam-Interruption-Based Vehicle Classiﬁer SystemIEEE Transactions on Intelligent Transportation Systems 14(3): 1043-1052Download
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This paper presents the design and development of a novel optical vehicle classifier system, which is based on interruption of laser beams, that is suitable for use in places with poor transportation infrastructure. The system can estimate the speed, axle count, wheelbase, tire diameter, and the lane of motion of a vehicle. The design of the system eliminates the need for careful optical alignment, whereas the proposed estimation strategies render the estimates insensitive to angular mounting errors and to unevenness of the road. Strategies to estimate vehicular parameters are described along with the optimization of the geometry of the system to minimize estimation errors due to quantization. The system is subsequently fabricated, and the proposed features of the system are experimentally demonstrated. The relative errors in the estimation of velocity and tire diameter are shown to be within 0.5% and to change by less than 17% for angular mounting errors up to 30°. In the field, the classifier demonstrates accuracy better than 97.5% and 94%, respectively, in the estimation of the wheelbase and lane of motion and can classify vehicles with an average accuracy of over 89.5%.
- Popular Article2013Development minus green shootsThe Hindu, 13 February 2013
By exempting some projects on forest land from gram sabha consent, the government has undermined the rights of local communities and their crucial role in protecting the environment.
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- Book Chapter2013Arunachal macaque Macaca munzala (Sinha, Datta, Madhusudan and Mishra 2005)Pages 198-210 in A. J. T. Johnsingh & N. Manjrekar (editors) Mammals of South Asia – Volume 1. Universities Press, Hyderabad, India
- Book Chapter2013The Monkey in the Town’s Commons, Revisited: An Anthropogenic History of the Indian Bonnet MacaquePages 187-208 in S. Radhakrishna et al. (eds.), The Macaque Connection: Cooperation and Conflict between Humans and Macaques, Developments in Primatology: Progress and Prospects, Springer, New Delhi
- Book2013The Macaque Connection: Cooperation and Conflict between Humans and MacaquesSeries: Developments in Primatology: Progress and Prospects, Vol. 43, Springer, New Delhi
Most successful among the non-human primates in terms of geographical distribution and adaptability to ecological habitats, macaques have existed for many thousands of years in close contact with modern humans, the only primate more successful than them. Centuries-old literary works attest to the fact that macaques have always been an intrinsic part of human lives and imaginations. In their interactions with humans, macaques play multiple roles that often transcend the boundaries of categorization. They are often, simultaneously, wildlife and domestic pets, sentient beings and experimental subjects, crop-raiding pests and religious symbols. In many parts of the tropics, macaques are an economic resource for human communities, as they provide meat and money through tourism and the animal trade. Equally, they cause much damage and bring about great economic losses due to their crop- and house-raiding tendencies. A more recent cause for alarm has been the possibility of transmission of diseases to humans due to contact with macaques. Across Asia, macaques, perhaps more than any other animal species, exemplify the multiple facets of synurbization and the conservation problems of commensal species. Humans and macaques associate in rather remarkable ways, and this volume explores the tone and nature of those human-macaque connections by focusing on various forms of interactions between macaques and humans, change in human attitudes vis-à-vis macaques over the ages, cultural views on macaques, human-macaque conflict and its conservation implications. Its holistic perspective of the myriad aspects that illustrate the singular relationship between men and macaques makes it essential reading not only for primatologists and anthropologists but also for anyone interested in the intricacies of human-animal relations.