Scientist, Eastern Himalaya
Rohit is interested in frugivory, seed dispersal and conservation of tropical forests and its inhabitants. His doctoral research focused on understanding the frugivory and seed dispersal by hornbills and their conservation status in Arunachal Pradesh. Subsequently, he has been involved in conducting a survey of hornbills across five states in north-east India to understand change in their distribution in the last 20 years. He is also involved in a telemetry study to understand the movement patterns of hornbills and is part of the Hornbill Watch team that aims to document hornbill presence across the country.
His prior research has focused on understanding processes that govern the diversity patterns of amphibians in the wet forests of Western Ghats and in conducting surveys for large mammals in north-east India. His other interests include reading non-fiction and listening to Hindustani Classical Music.
Endangered bird distributions
Understanding distributions of White-bellied Heron and White-winged Duck
- Dataset2016Data from: Spatial and temporal variation in hornbill densities in Namdapha Tiger Reserve, Arunachal Pradesh, north-east IndiaDOI: doi:10.5061/dryad.qr068
- Journal Article2016Abundance estimates of the Rufous-necked hornbill (Aceros nipalensis), and characterisation of a montane subtropical forest in the Indian Eastern Himalaya.Indian Birds, Vol. 12, 4 & 5 14 November 2016
- Journal Article2015Looking beyond parks: the conservation value of unprotected areas for hornbills in Arunachal Pradesh, Eastern HimalayaOryx, 49:303-311Download
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The loss of tropical forests and associated biodiversity is a global concern. Conservation efforts in tropical countries such as India have mostly focused on state-administered protected areas despite the existence of vast tracts of forest outside these areas. We studied hornbills (Bucerotidae), an ecologically important vertebrate group and a flagship for tropical forest conservation, to assess the importance of forests outside protected areas in Arunachal Pradesh, north-east India. We conducted a state-wide survey to record encounters with hornbills in seven protected areas, six state-managed reserved forests and six community-managed unclassed forests. We estimated the density of hornbills in one protected area, four reserved forests and two unclassed forests in eastern Arunachal Pradesh. The state-wide survey showed that the mean rate of encounter of rufous-necked hornbills Aceros nipalensis was four times higher in protected areas than in reserved forests and 22 times higher in protected areas than in unclassed forests. The mean rate of encounter of wreathed hornbills Rhyticeros undulatus was twice as high in protected areas as in reserved forests and eight times higher in protected areas than in unclassed forests. The densities of rufous-necked hornbill were higher inside protected areas, whereas the densities of great hornbill Buceros bicornis and wreathed hornbill were similar inside and outside protected areas. Key informant surveys revealed possible extirpation of some hornbill species at sites in two protected areas and three unclassed forests. These results highlight a paradoxical situation where individual populations of hornbills are being lost even in some legally protected habitat, whereas they continue to persist over most of the landscape. Better protection within protected areas and creative community- based conservation efforts elsewhere are necessary to maintain hornbill populations in this biodiversity-rich region.
- Journal Article2015Reduced hornbill abundance associated with low seed arrival and altered recruitment in a hunted and logged tropical forestPLOSOne; DOI: 10.1371/journal.pone.0120062
Logging and hunting are two key direct threats to the survival of wildlife in the tropics, and also disrupt important ecosystem processes. We investigated the impacts of these two factors on the different stages of the seed dispersal cycle, including abundance of plants and their dispersers and dispersal of seeds and recruitment, in a tropical forest in north-east India. We focused on hornbills, which are important seed dispersers in these forests, and their food tree species. We compared abundances of hornbill food tree species in a site with high logging and hunting pressures (heavily disturbed) with a site that had no logging and relatively low levels of hunting (less disturbed) to understand logging impacts on hornbill food tree abundance. We compared hornbill abundances across these two sites. We, then, compared the scatter-dispersed seed arrival of five large-seeded tree species and the recruitment of four of those species. Abundances of hornbill food trees that are preferentially targeted by logging were two times higher in the less disturbed site as compared to the heavily disturbed site while that of hornbills was 22 times higher. The arrival of scatter-dispersed seeds was seven times higher in the less disturbed site. Abundances of recruits of two tree species were significantly higher in the less disturbed site. For another species, abundances of younger recruits were significantly lower while that of older recruits were higher in the heavily disturbed site. Our findings suggest that logging reduces food plant abundance for an important frugivore-seed disperser group, while hunting diminishes disperser abundances, with an associated reduction in seed arrival and altered recruitment of animal-dispersed tree species in the disturbed site. Based on our results, we present a conceptual model depicting the relationships and pathways between vertebrate-dispersed trees, their dispersers, and the impacts of hunting and logging on these pathways.
- Dataset2015Data of a study investigating impacts of hunting and logging on abundance of hornbills, dispersed seeds and recuits in north-east Indiahttp://dx.doi.org/10.5061/dryad.1cf35
A study was carried out to investigate impacts of logging and hunting on hornbills (which are important seed dispersers), their large-seeded food plants, arrival of scatter-dispersed seeds of these plants and the recruitment pattern of these plants across a site experiencing logging and hunting pressures and a protected area site which did not experience these anthropogenic pressures. The associated data of the study is uploaded here.
- Journal Article2015Fruit resource tracking by hornbill species at multiple scales in a tropical forest in IndiaJournal of Tropical Ecology, 31:477-490Download
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The fruit-tracking hypothesis predicts a positive association between frugivores and fruit abundance over space and time.We documented hornbill diets and examined the relationship between fruit abundance and abundance of three hornbill species (Buceros bicornis, Rhyticeros undulatus and Aceros nipalensis) in the Eastern Himalaya from 2009– 2012. The study was carried out at three scales: at the largest scale of the study area (15km2), at the intermediate scale – eight 3-ha patches within the study area and at the smallest scale of individual fruiting trees.Ninety-one per cent of the 64 foraging sightings of the great hornbill were on figs while more than 50% of the foraging sightings of the wreathed (83) and rufous-necked hornbills (87) were on non-fig fruits. At the largest scale, wreathed hornbill abundance and ripe fruit abundance peaked in the non-breeding season. At the intermediate scale, wreathed hornbill abundance was positively associated with non-fig fruit availability while rufous-necked hornbill abundance was negatively associated with non-fig fruit availability. At the smallest scale, great and rufous-necked hornbill abundances were correlatedwith fig and non-fig fruit crop sizes, respectively. The three hornbill species track fruit availability at different scales based on diet, which has implications for their role in seed dispersal.
- Book Chapter2015Hope for hornbillsIn: Allison Hegan (Ed.), Endangered Tales.
- Journal Article2015Diet and foraging behaviour of Purple Cochoa Cochoa purpurea in Namdapha National Park, IndiaForktail, 30, 145-147
- Journal Article2015Seed dispersal by avian frugivores: non-random heterogeneity at fine scales.Biotropica 47(1): 77-84.Download
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Seed dispersal studies have primarily examined dispersal as a function of distance from the parent tree and/or heterogeneity in dispersal due to animal use of nesting, roosting and sleeping sites. However, non-random heterogeneity in seed dispersal is also likely to result from the post-foraging behavior and movement of frugivores which prefer certain trees. To characterize variation in seed rain at fine scales, we studied the dispersal curve of Prunus ceylanica, a primarily bird-dispersed species. We compared seed rain at conspecifics, heterospecific fruiting trees with similar frugivore assemblages, emergent trees, and the landscape surrounding these trees. Seed rain of P. ceylanica was found to peak globally under the canopy of conspecifics but to peak locally under the canopy and immediate neighborhood of heterospecific fruiting trees. Our results demonstrate that seed rain is highly clumped even at fine spatial scales. A large proportion of seeds are dispersed in specific, localized regions. This variation can have important implications for plant population dynamics and might significantly alter the impact of post-dispersal processes. Seed dispersal models may need to incorporate this heterogeneity to explain manifestations of spatially explicit dynamics like mixed species ‘orchards’.
- Report2015Hornbill Watch Report June 2014 to May 2015May 2015, www.hornbills.inDownload
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An update that summarises the information obtained on Indian hornbills contributed by people on the Hornbill Watch website for one year (June 2014 to May 2015).