- Journal ArticleIn pressMixed fortunes: old expansion and recent decline in population size of a subtropical montane primate, the Arunachal macaquePLoS One
- Journal ArticleIn pressGoral Nemorhaedus goralIn: A. J. T. Johnsingh and N. Manjrekar (eds.) Mammals of South Asia: ecology, behaviour and conservation. Permanent Black, Delhi.
- Journal ArticleIn pressSerow Nemorhaedus sumatraensisIn: A. J. T. Johnsingh and N. Manjrekar (eds.) Mammals of South Asia: ecology, behaviour and conservation. Permanent Black, Delhi.
- Journal ArticleIn pressAnts on Clerodendrum infortunatum: Disentangling Effects of Larceny and HerbivoryEnvironmental Entomology
Nectar larcenists extract nectar from flowers without pollinating them. A reasonable expectation is that any form of nectar larceny should have a detrimental effect on the plant’s reproductive success. However, studies reveal an entire range of effects, from highly negative to highly positive. This variation in effect may be partly explained by additional, unmeasured, effects of nectar larcenists on plants. In a study system where two ant species Tapinoma melanocephalum (Fabr.) (Hymenoptera: Formicidae) and Trichomyrmex destructor (Jerd.) (Hymenoptera: Formicidae) act as nectar larcenists, we examined the effect of larceny on the female reproductive success of Clerodendrum infortunatum Gaertn. (Lamiales: Lamiaceae) in rain forest fragments of the Western Ghats, India. This was done through a combination of field observations and a series of field experiments looking at the effects of excluding ants from inflorescences. We found that T. destructor reduces fruit set considerably. Rather than this being a consequence of nectar larceny, however, our experiments show that the negative effect arises instead from the herbivorous behavior of the ant. At a population level, both ant species prefer edges over interiors of forest patches, spatially concentrating the interaction zone to forest edges. Simultaneously considering multiple ecological interactions and disentangling their relative contributions might explain the large variation across species in the observed effect of larceny. The overall population effect of nectar larceny and herbivory is likely to depend on the spatial structuring of plants and ants.
- Journal ArticleIn pressDistribution and activity pattern of stone marten Martes foina in relation to prey and predatorsMammalian Biology; https://doi.org/10.1016/j.mambio.2018.09.013Download
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Small carnivores are expected to optimize their activity to maximize prey capture and minimize their encounter with predators. We assessed the activity pattern of the stone marten
Martes foinain relation to its potential prey, the Himalayan woolly hare Lepus oiostolus and the Royle’s pika Ochotona roylei, and its predators, the red fox Vulpes vulpesand the free-ranging dog Canis familiaris. Using three years of camera trapping data from the Indian Trans-Himalaya, we estimated individual and pair-wise spatio-temporal niche width and overlap, respectively, using Levins’ asymmetric index. Stone martens showed limited space use (spatial niche width 0.16) and nocturnal activity (temporal niche width 0.35). They had high temporal (0.75) and low spatial overlap (0.05) with hares; while they had relatively low temporal (0.33) but higher spatial overlap (0.29) with pikas. Red foxes showed relatively high temporal (1.21) and spatial (0.75) overlap with martens, while free-ranging dogs showed low temporal (0.23) and spatial (0.03) overlap with martens. Although restricted space and time use by pikas might help martens track pikas even with relatively low spatio-temporal overlap, martens may be benefiting from higher temporal overlap with hares. While martens seem to be co-existing with foxes, their nocturnal activity might be driven by a trade-off between consuming prey and avoidance of diurnal predators like dogs.
- Journal Article2019Sympatric cranes in northern Australia: abundance, breeding success, habitat preference and dietEmu - Austral Ornithology 119(1): 79-89. https://doi.org/10.1080/01584197.2018.1537673Download
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Sympatric breeding of Sarus Cranes (Antigone antigone) and Brolga (A. rubicunda) occurs only in northern Queensland, Australia but factors contributing to this unique sympatry are unknown. Large-scale developments currently planned in this region, with potentially major impacts on cranes, create an urgent need to understand the ecological requirements of each crane species. We carried out a multi-floodplain landscape-scale survey during April-May 2017 and derived metrics for several ecological aspects for the first time for both crane species. The abundance of the two species differed between the floodplains. Both crane species synchronised nest-initiation with rainfall (November to March). Breeding success was higher than past estimates anywhere, with 60% of Sarus Crane pairs and 50% of Brolga pairs fledging chicks. Sarus Cranes preferred four riverine Eucalyptus-dominated regional ecosystems, with 10% using open habitats. Brolgas preferred two non-wooded regional ecosystems, but 32% shared Eucalyptus-dominated regional ecosystems with Sarus Cranes. Stable isotope analyses revealed Sarus diet to be comprised of more diverse vegetation than Brolgas, while Brolgas fed across a wider range of trophic levels. The ecology of Gulf cranes closely matched habits of Sarus Cranes in south Asia, despite disparate conditions suggesting considerable species plasticity. The diverse habitats of the Gulf and varying diet appear to facilitate the cranes’ sympatry, and our study provides basic data for developing long-term conservation plans in the face of development activities.
- Journal Article2019Sampling bias in snow leopard population estimation studiesPopulation Ecology 10.1002/1438-390X.1027Download
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Accurate assessments of the status of threatened species and their conservation planning require reliable estimation of their global populations and robust monitoring of local population trends. We assessed the adequacy and suitability of studies in reliably estimating the global snow leopard (Panthera uncia) population. We compiled a dataset of all the peer-reviewed published literature on snow leopard population estimation. Metadata analysis showed estimates of snow leopard density to be a negative exponential function of area, suggesting that study areas have generally been too small for accurate density estimation, and sampling has often been biased towards the best habitats. Published studies are restricted to six of the 12 range countries, covering only 0.3–0.9% of the presumed global range of the species. Re-sampling of camera trap data from a relatively large study site (c.1684 km2) showed that small-sized study areas together with a bias towards good quality habitats in existing studies may have overestimated densities by up to five times. We conclude that current information is biased and inadequate for generating a reliable global population estimate of snow leopards. To develop a rigorous and useful baseline and to avoid pitfalls, there is an urgent need for (a) refinement of sampling and analytical protocols for population estimation of snow leopards (b) agreement and coordinated use of standardized sampling protocols amongst researchers and governments across the range, and (c) sampling larger and under-represented areas of the snow leopard's global range.
- Journal Article2019Roosting ecology of Black-Headed Ibis (Threskiornis melanocephalus) in urban and rural areas of southern Rajasthan, IndiaWaterbirds 42(1): 51-60.
The roosting ecology of most waterbird species is poorly known and even less is known from southern Asia, where many species inhabit human-modified areas. Roosting ecology of the Black-headed Ibis (Threskiornis melanocephalus) was studied in urban and rural settings in southern Rajasthan, India. Analyses focused on assessing whether site characteristics varied between nest sites, urban and rural roost sites, and paired sites (i.e., a waterbird roost site near Black-headed Ibis roosts but without Black-headed Ibis). Additionally, the hypothesis that factors affecting Black-headed Ibis numbers at roosts would be similar at urban and rural sites was tested. Tree characteristics (canopy cover, girth at breast height) were different (P < 0.05) between nest and roost sites. Urban roost sites experienced 2.3 times greater disturbance than rural roost sites. Paired site characteristics were similar to urban roost sites (multi response permutation procedure, significance of δ = 0.3), but were dissimilar to rural roost sites. Co-occurring roosting bird assemblages were significantly different between roosts and paired sites (significance of δ < 0.01) in urban and rural settings. Black-headed Ibis numbers at urban roosts were influenced by multiple variables, but models showed considerable ambiguity at rural sites. Results strongly suggest that including roost sites in a species status assessment is important.
- Journal Article2018The role of artificial habitats and rainfall patterns in the unseasonal nesting of Sarus Cranes (Antigone antigone) in south AsiaWaterbirds 41(1): 80-86.
Sarus Cranes (Antigone antigone) in south Asia breed during the rainy season (monsoon), with few nests initiated outside of the monsoon. Several hypothesis have been put forth to explain the unseasonal nesting outside the monsoon, but a careful evaluation of the hypotheses has been absent. Using a multi-year (2004-2017), multi-scale (four Indian states) data set, this study explored the factors potentially responsible for unseasonal nesting by Sarus Cranes. Nests outside the monsoon were very rare (0.3% of all nests) and were initiated when Sarus Crane pairs were in areas with artificial water sources (irrigation canals or reservoirs) or faced abnormal monsoonal conditions. Unseasonal nests were initiated only when breeding pairs had been unsuccessful in raising chicks in the previous primary nesting season. Altered cropping patterns associated with increased artificial irrigation and changing rainfall patterns appear responsible for unseasonal nesting in Sarus Cranes. Nesting of this species outside the monsoon may increase in response to the increasing changes in cropping patterns and changing rainfall conditions.
- Journal Article2018Temporal variations in patterns of Escherichia coli strain diversity and antimicrobial resistance in the migrant Egyptian VultureInfection Ecology and Epidemeology 8:1, 1450590.
Aims: Multiple antimicrobial resistance in Escherichia coli of wild vertebrates is a global concern with scarce assessments on the subject from developing countries that have high human-wild species interactions. We studied the ecology of E. coli in a wintering population of Egyptian Vultures in India to understand temporal changes in both E. coli strains and patterns of antimicrobial resistance.
Methods and Results: We ribotyped E. coli strains and assessed antimicrobial resistance from wintering vultures at a highly synanthropic carcass dump in north-west India. Both E. coli prevalence (90.32%) and resistance to multiple antimicrobials (71.43%) were very high. Clear temporal patterns were apparent. Diversity of strains changed and homogenized at the end of the Vultures’ wintering period, while the resistance pattern showed significantly difference inter-annually, as well as between arrival and departing individuals within a wintering cycle.
Significance of study: The carcass dump environment altered both E. coli strains and multiple antimicrobial resistance in migratory Egyptian Vultures within a season. Long-distance migratory species could therefore disseminate resistant E. coli strains across broad geographical scales rendering regional mitigation strategies to control multiple antimicrobial resistance in bacteria ineffective.
- Journal Article2018Hornbill Watch: A citizen science initiative for Indian hornbillsIndian Birds, 14:65-70Download
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Hornbills are conspicuous and well-known birds with nine species occurring in India. While several hornbill species have been studied extensively in some parts of India, there is a knowledge gap about their distribution, population size, and adaptations to rapidly changing habitats. Most research and conservation efforts are often focused on single or few species within protected areas. Hornbill Watch (henceforth, HW) is an online platform created specifically to record public sightings of hornbills from anywhere in India. The idea is to encourage birders, nature enthusiasts, and photographers to share information on hornbill presence, behaviour, and conservation-related issues. The main objective is to generate baseline information using sight records and enable long-term monitoring of these species by encouraging citizen participation. HW was launched in June 2014, and up to February 2017 had received 938 records from 430 contributors across India, from 26 States and three Union Territories. States from where most sightings were reported were Karnataka, Maharashtra, Tamil Nadu, Assam, and Arunachal Pradesh. Species were reported from both inside (41%), and outside Protected Areas (59%; henceforth, PA). Hornbills were reported from 70 PAs. Fifty-one records of nesting were reported for all species from inside and outside PAs, while 27 records of communal roosting were reported for some species. The data obtained thus far has yielded some useful information and insights,and has the potential for enhancing our understanding of current hornbill distribution patterns, and for identifying important sites for conservation/protection.
- Journal Article2018Breeding biology of Great Hornbill Buceros bicornis in tropical rainforest and human-modified plantation landscape in Western Ghats, IndiaOrnithological Science, 17:205-216Download
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Loss of mature tropical forests to agricultural expansion often creates landscapes with forest fragments embedded within a matrix of human-modified habitats and land uses. Such habitat fragmentation may be detrimental to species with specialized habitat and foraging requirements and their ability to persist in such landscapes may depend on their adaptability to habitat modification. Great Hornbills Buceros bicornis, among the largest birds in Asian tropical rainforests, depend on large trees for nesting and a diverse array of patchily distributed fruiting trees. In the human-modified landscape of the Anamalai Hills, India, we compared the breeding biology and nesting behaviour of Great Hornbills in contiguous rainforest (N=3 nests) and in modified habitat consisting of coffee plantations and rainforest fragments (N=5 nests). The nesting cycle of seven of the eight nests monitored varied between 114 and 130 days. Nest provisioning behaviour was similar in contiguous forest and modified habitat in terms of visitation and food delivery rates, but visitation tended to be higher and food delivery rate lower during the nestling phase than during incubation. As expected, tree density and native food plant diversity were lower in modified habitat than in continuous forest. The diversity of food provisioned was lower in modified habitat with a 57.5% dietary overlap with contiguous forest. Hornbills in the modified habitat of coffee plantations used non-native tree species for nesting and foraging, indicating their adaptability to modified landscapes.
- Journal Article2018eBird in Asia: standardised tools for birdwatchersBirdingASIA, 29:105-108
- Journal Article2018Seasonal variation in wildlife roadkills in plantations and tropical rainforest in the Anamalai Hills, Western Ghats, IndiaCurrent Science. 114(3): 619-626.
- Journal Article2018Context-dependent interactive effects of non-lethal predation on larvae impact adult longevity and body compositionPLoS ONE. 13(2): e0192104
Full text available here:
Predation impacts development, behavior and morphology of prey species thereby shaping their abundances, distribution and community structure. Non-lethal threat of predation, specifically, can have a strong influence on prey lifehistory characteristics. While investigations often focus on the impact of predation threat on prey in isolation, tests of its interactive effects with food availability and resource competition on prey survival and fitness can improve understanding of costs, benefits and trade-offs of anti-predator strategies. This study, involving Aedes aegypti mosquitoes as a model organism, investigates both simple and interactive effects of predation threat during the larval stage on survival, size at and time to maturity, stored teneral reserves of glycogen, protein and lipid in adults, and adult longevity. Our results show that development times of mosquito larvae were increased (by 14.84% in males and by 97.63% in females), and size of eclosing adults decreased (by 62.30% in males and by 58.33% in females) when exposed to lowered nutrition and elevated intraspecific competition, but that predation had no detectable effect on these simple traits. Teneral reserves of glycogen, protein and lipid and adult longevity were positively correlated with adult body size. Non-lethal predation threat had significant interactive effects with nutrition and larval competition on teneral reserves in males and adult longevity in males and females. The sexes responded differently to conditions encountered as larvae, with the larval environment affecting development and adult characteristics more acutely for females than for males. The outcome of this study shows how threat of predation on juveniles can have long-lasting effects on adults that are likely to impact mosquito population dynamics and that may impact disease transmission.
- Journal Article2018Common Starling Sturnus vulgaris in Anini, Arunachal PradeshIndian Birds 14(3): 90
- Journal Article2018Whose habitat is it anyway? Role of natural and anthropogenic habitats in conservation of charismatic speciesTropical Conservation Science 11: 1-5.Download
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Developmental activities have been one of the major drivers of conversion of natural forest areas into mosaics of forest fragments, agriculture, and plantations, threatening the existence of wildlife species in such altered landscapes. Most conservation research and actions are protected area centric and seldom addresses the importance of landscape matrices around these protected areas in providing habitats to a wide range of species. In this article, we bring out the crucial role of natural and anthropogenic habitats for the existence of three charismatic species, namely, Asian elephants, leopard, and lion-tailed macaques. The larger public perception of where the animals should be and where the animals actually are is also discussed. We emphasize that, while habitat generalists often adapt behaviorally and ecologically to modified landscapes, habitat specialists, such as the lion-tailed macaques could find survival harder, with increasing anthropogenic pressures and loss of their habitats.
- Journal Article2018Local community neutralizes traditional wolf traps and builds a stupaOryx