- Journal Article2016Irrigation demands aggravate fishing threats to river dolphins in NepalBiological Conservation, http://dx.doi.org/10.1016/j.biocon.2016.10.026Download
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Riverine species are adapted to natural habitat changes caused by seasonal flood-pulses. However, abrupt river channel changes following flooding events intersect with social systems of land and water management (e.g. agriculture, fisheries) and in turn generate significant consequences for conservation of endangered aquatic species. We investigated tradeoffs between changing river habitat availability and exposure to fishing intensity for a small population of Ganges River dolphins Platanista gangetica gangeticain the Karnali basin of Nepal. A major natural flooding event in the Karnali basin in 2010 caused the river channel to shift from the Geruwa (flows through a protected area where fishing is restricted) to the Karnali channel (high fishing activity, agriculture-dominated), where dolphins moved in response. Based on our survey data (2009–2015) and long-term hydrological trends in the basin, we found that irrigation diversions since 2012 had aggravated fishing impacts on dolphins, suggesting that their new habitat had become an ‘ecological trap’. Regression models showed that at low river depths, fishing intensity negatively affected dolphin abundance, but at higher depths no effect of fishing was observed. Two records of dolphin bycatch in gillnets confirmed this, as both events corresponded with periods of sudden increase in water abstraction for irrigation. Overall, dolphin distribution shifted downstream and the population declined from 11 in 2012 to 6 in 2015. Effective protection of this river dolphin population from extinction will require the Government of Nepal to prioritize ecologically adequate river flow regimes for implementing efficient irrigation schemes and adaptive fisheries regulations in the Karnali basin.
- 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’.
- 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.
- Journal Article2015Diet and foraging behaviour of Purple Cochoa Cochoa purpurea in Namdapha National Park, IndiaForktail, 30, 145-147
- Journal Article2015Status of the mountain ungulate prey of the Endangered snow leopard Panthera uncia in the Tost Local Protected Area, South Gobi, MongoliaOryx, doi:10.1017/S0030605314001203
- Journal Article2015Perceptions of priority issues in the conservation of biodiversity and ecosystems in IndiaBiological Conservation, 187: 201-211Download
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We report on the results of a country-wide survey of people’s perceptions of issues relating to the con- servation of biodiversity and ecosystems in India. Our survey, mainly conducted online, yielded 572 respondents, mostly among educated, urban and sub-urban citizens interested in ecological and environ- mental issues. 3160 ‘‘raw’’ questions generated by the survey were iteratively processed by a group of ecologists, environmental and conservation scientists to produce the primary result of this study: a sum- marized list of 152 priority questions for the conservation of India’s biodiversity and ecosystems, which range across 17 broad thematic classes. Of these, three thematic classes—‘‘Policy and Governance’’, ‘‘Biodiversity and Endangered Species’’ and ‘‘Protection and Conservation’’—accounted for the largest number of questions. A comparative analysis of the results of this study with those from similar studies in other regions brought out interesting regional differences in the thematic classes of questions that were emphasized and suggest that local context plays a large role in determining emergent themes. We believe that the ready list of priority issues generated by this study can be a useful guiding framework for conservation practitioners, researchers, citizens, policy makers and funders to focus their resources and efforts in India’s conservation research, action and funding landscape.
- Journal Article2015Invasive alien species in relation to edges and forest structure in tropical rainforest fragments of the Western GhatsTropical Ecology 56: 233-244Download
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The impact of invasive alien species on native ecosystems is a major conservation issue in the tropics. This study in the rainforest fragments of Anamalai hills, in the Western Ghats biodiversity hotspot, assessed the effects of distance from edges and forest structure on the occurrence and abundance of three invasive alien species (Chromolaena odorata, Lantana camara, and Maesopsis eminii). Replicate line transects were laid from the edges into the interiors of four fragments varying in disturbance level and area (32 ha – 200 ha). Densities of alien species in the protected site were lower than in the three disturbed fragments. Maesopsis eminii occurred at highest density (382 trees/ha) in the highly disturbed site where it also showed prolific regeneration (1510 saplings/ha). The invasive alien species showed no clear edge-to-interior pattern, instead their abundance appeared to be localized and related in a site-specific manner to disturbances such as presence of Eucalyptus plantation, canopy openings, and trails.
- Journal Article2015Prey abundance and leopard diet in a plantation and rainforest landscape, Anamalai Hills, Western GhatsCurrent Science 109: 323-330.Download
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Leopards use a wide range of habitats from natural forests to plantations in human-dominated landscapes. Within interface areas, understanding leopard ecology and diet can help in conservation management and conflict avoidance. In a fragmented rainforest and plantation landscape in southern India, we examined diet of large carnivores (with a focus on leopards) using scat analysis with DNA-based identification of predator species, and estimated relative abundance of prey species in different land uses through transect surveys. Large carnivores predominantly consumed wild prey species (98.1%) and domestic prey species contributed <2% to overall prey biomass. For leopards, four wild prey species (Indian muntjac, Indian spotted chevrotain, sambar and Indian porcupine) contributed 95.1% of prey biomass, with the rest being minor wild prey species (no livestock in identified scats). Wild prey species occurred across the landscape but varied in relative abundance by land-use type, with forest fragments supporting higher abundance of many species relative to tea and coffee plantations. As large carnivores mainly depend on wild prey and rainforest fragments act as refuges for these mammals within the tea and coffee plantations, it is important to continue to retain or restore these forest fragments.
- Journal Article2015Distribution, relative abundance, and conservation status of Asian elephants in Karnataka, southern IndiaBiological Conservation 187:34-40Download
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Karnataka state in southern India supports a globally significant—and the country’s largest—population of the Asian elephant Elephas maximus. A reliable map of Asian elephant distribution and measures of spatial variation in their abundance, both vital needs for conservation and management action, are unavailable not only in Karnataka, but across its global range. Here, we use various data gathered between 2000 and 2015 to map the distribution of elephants in Karnataka at the scale of the smallest forest management unit, the ‘beat’, while also presenting data on elephant dung density for a subset of ‘elephant beats.’ Elephants occurred in 972 out of 2855 forest beats of Karnataka. Sixty percent of these 972 beats—and 55% of the forest habitat—lay outside notified protected areas (PAs), and included lands designated for agricultural production and human dwelling. While median elephant dung density inside protected areas was nearly thrice as much as outside, elephants routinely occurred in or used habitats outside PAs where human density, land fraction under cultivation, and the interface between human-dominated areas and forests were greater. Based on our data, it is clear that India’s framework for elephant conservation— which legally protects the species wherever it occurs, but protects only some of its habitats—while being appropriate in furthering their conservation within PAs, seriously falters in situations where elephants reside in and/or seasonally use areas outside PAs. Attempts to further elephant conservation in production and dwelling areas have extracted high costs in human, elephant, material and monetary terms in Karnataka. In such settings, conservation planning exercises are necessary to determine where the needs of elephants—or humans—must take priority over the other, and to achieve that in a manner that is based not only on reliable scientific data but also on a process of public reasoning.
- Journal Article2015Does mixed-species flocking influence how birds respond to a gradient of land-use intensity?Proceedings of the Royal Society B 282: 20151118.Download
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Conservation biology is increasingly concerned with preserving interactions among species such as mutualisms in landscapes facing anthropogenic change. We investigated how one kind of mutualism, mixed-species bird flocks, influences the way in which birds respond to different habitat types of varying land-use intensity. We use data from a well-replicated, large-scale study in Sri Lanka and the Western Ghats of India, in which flocks were observed inside forest reserves, in ‘buffer zones' of degraded forest or timber plantations, and in areas of intensive agriculture. We find flocks affected the responses of birds in three ways: (i) species with high propensity to flock were more sensitive to land use; (ii) different flock types, dominated by different flock leaders, varied in their sensitivity to land use and because following species have distinct preferences for leaders, this can have a cascading effect on followers' habitat selection; and (iii) those forest-interior species that remain outside of forests were found more inside flocks than would be expected by chance, as they may use flocks more in suboptimal habitat. We conclude that designing policies to protect flocks and their leading species may be an effective way to conserve multiple bird species in mixed forest and agricultural landscapes.
PDF also available here: http://dx.doi.org/10.1098/rspb.2015.1118
- Journal Article2015Tracking seed fates of tropical tree species: evidence for seed caching in a tropical forest in north-east IndiaPLoS ONEDOI: 10.1371/journal.pone.0134658Download
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Rodents affect the post-dispersal fate of seeds by acting either as on-site seed predators or as secondary dispersers when they scatter-hoard seeds. The tropical forests of north-east India harbour a high diversity of little-studied terrestrial murid and hystricid rodents. We examined the role played by these rodents in determining the seed fates of tropical evergreen tree species in a forest site in north-east India. We selected ten tree species (3 mammal-dispersed and 7 bird-dispersed) that varied in seed size and followed the fates of 10,777 tagged seeds. We used camera traps to determine the identity of rodent visitors, visitation rates and their seed-handling behavior. Seeds of all tree species were handled by at least one rodent taxon. Overall rates of seed removal (44.5%) were much higher than direct on-site seed predation (9.9%), but seed-handling behavior differed between the terrestrial rodent groups: two species of murid rodents removed and cached seeds, and two species of porcupines were on-site seed predators. In addition, a true cricket,Brachytrupessp., cached seeds of three species underground. We found 309 caches formed by the rodents and the cricket; most were single-seeded (79%) and seeds were moved up to 19 m. Over 40% of seeds were re-cached from primary cache locations, while about 12% germinated in the primary caches. Seed removal rates varied widely amongst tree species, from 3% inBeilschmiedia assamicato 97% inActinodaphne obovata. Seed predation was observed in nine species.Chisocheton cumingianus(57%) andPrunus ceylanica(25%) had moderate levels of seed predation while the remaining species had less than 10% seed predation. We hypothesized that seed traits that provide information on resource quantity would influence rodent choice of a seed, while traits that determine resource accessibility would influence whether seeds are removed or eaten. Removal rates significantly decreased (p< 0.001) while predation rates increased (p= 0.06) with seed size. Removal rates were significantly lower for soft seeds (p= 0.002), whereas predation rates were significantly higher on soft seeds (p= 0.01). Our results show that murid rodents play a very important role in affecting the seed fates of tropical trees in the Eastern Himalayas. We also found that the different rodent groups differed in their seed handling behavior and responses to changes in seed characteristics.
- Journal Article2015Fish community reassembly after a coral mass mortality: higher trophic groups are subject to increased rates of extinctionEcology Letters 18(5): 451–461Download
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Since Gleason and Clements, our understanding of community dynamics has been influenced by theories emphasising either dispersal or niche assembly as central to community structuring. Determining the relative importance of these processes in structuring real-world communities remains a challenge. We tracked reef fish community reassembly after a catastrophic coral mortality in a relatively unfished archipelago. We revisited the stochastic model underlying MacArthur and Wilson’s Island Biogeography Theory, with a simple extension to account for trophic identity. Colonisation and extinction rates calculated from decadal presence-absence data based on (1) species neutrality, (2) trophic identity and (3) site-specificity were used to model post-disturbance reassembly, and compared with empirical observations. Results indicate that species neutrality holds within trophic guilds, and trophic identity significantly increases overall model performance. Strikingly, extinction rates increased clearly with trophic position, indicating that fish communities may be inherently susceptible to trophic downgrading even without targeted fishing of top predators.
- Journal Article2015Wetland loss and waterbird use of wetlands in Palwal district, Haryana, India: The role of agriculture, urbanization and conversion to fish pondsWetlands. DOI 10.1007/s13157-014-0600-8Download
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Wetlands in tropical and sub-tropical landscapes
are experiencing changes and loss due to urbanization and
intensive human use, but there is sparse detailed understanding
of how these affect use by wetland-dependent birds.
Urbanization and conversion of community wetlands to private
fish ponds are occurring rapidly in Haryana state in north
India. We conducted a study in Palwal district, Haryana in
2013–2014 to simultaneously understand (i) rates and reasons
for wetland loss between 1970s and 2000s, and (ii) relative
importance of location (towns/ villages versus those amid
agriculture) versus site-specific variables on the winter abundance of 31 waterbird species in these fish ponds. Wetland
extent reduced by 52 %, and average wetland size reduced by
42 % between 1970s and 2000s. Expansion of urban areas
converted 105 agricultural wetlands to town wetlands.
Wetlands of different locations could not be differentiated
using waterbird abundance suggesting that wetland conditions
have been homogenized, in part due to conversions to fish
ponds and in part due to urban expansions. Focal waterbird
abundance was affected more due to human activities relative
to location or vegetation. A complex combination of current
management practices and historical determinants of wetland persistence appear to be driving waterbird use of wetlands in
locations like Palwal.
- Journal Article2015Does livestock benefit or harm snow leopards?Biological Conservation, 190: 8-13
Large carnivores commonly prey on livestock when their ranges overlap. Pastoralism is the dominant land use type across the distributional range of the endangered snow leopard Panthera uncia. Snow leopards are often killed in retaliation against livestock depredation. Whether livestock, by forming an alternative prey, could potentially benefit snow leopards, or, whether livestock use of an area is detrimental to snow leopards is poorly understood. We examined snow leopard habitat use in a multiple use landscape that was comprised of sites varying in livestock abundance, wild prey abundance and human population size. We photographically sampled ten sites (average size 70 sq. km) using ten camera traps in each site, deployed for a period of 60 days. Snow leopard habitat use was computed as a Relative Use Index based on the total independent photographic captures and the number of snow leopard individuals captured at each site. We quantified livestock abundance, wild prey abundance, human population size and terrain ruggedness in each of the sites. Key variables influencing snow leopard habitat use were identified using Information Theory based model selection approach. Snow leopard habitat use was best explained by wild prey density, and showed a positive linear relationship with the abundance of wild ungulates. We found a hump-shaped relationship between snow leopard habitat use and livestock stocking density, with an initial increase in habitat use followed by a decline beyond a threshold of livestock density. Our results suggest that in the absence of direct persecution of snow leopards, livestock grazing and snow leopard habitat use are potentially compatible up to a certain threshold of livestock density, beyond which habitat use declines, presumably due to depressed wild ungulate abundance and associated anthropogenic disturbance.
- Journal Article2015Erosion of Traditional Marine Management Systems in the Face of Disturbances in the Nicobar ArchipelagoHuman Ecology, DOI 10.1007/s10745-015-9781-x
- Journal Article2015Landscape scale habitat suitability modelling of bats in the Western Ghats of India:Bats like something in their teaBiological Conservation 191: 529-536.Download
PDF, 1.92 MB
To conserve biodiversity it is imperative that we understand how different species respond to land use change, and determine the scales at which habitat changes affect species' persistence. We used habitat suitability models (HSMs) at spatial scales from 100–4000 m to address these concerns for bats in the Western Ghats of India, a biodiversity hotspot of global importance where the habitat requirements of bats are poorly understood. We used acoustic and capture data to build fine scale HSMs for ten species (Hesperoptenus tickelli, Miniopterus fuliginosus, Miniopterus pusillus, Myotis horsfieldii, Pipistrellus ceylonicus, Megaderma spasma, Hipposideros pomona, Rhinolophus beddomei, Rhinolophus indorouxii and Rhinolophus lepidus) in a tea-dominated landscape. Small (100–500 m) scale habitat variables (e.g. percentage tea plantation cover) and distances to habitat features (e.g. distance to water) were the strongest predictors of bat occurrence, likely due to their high mobility, which enables them to exploit even small or isolated foraging areas. Most species showed a positive response to coffee plantations grown under native shade and to forest fragments, but a negative response to more heavily modified tea plantations. Two species were never recorded in tea plantations. This is the first study of bats in tea planta- tions globally, and the first ecological Old World bat study to combine acoustic and capture data. Our results suggest that although bats respond negatively to tea plantations, tea-dominated landscapes that also contain forest fragments and shade coffee can nevertheless support many bat species.
- Journal Article2015Demographic superiority with increased logging in tropical understorey birdsJournal of Applied Ecology, 52 (5): 1374-1380
- Journal Article2015Seagrass Herbivory Levels Sustain Site-Fidelity in a Remnant Dugong PopulationSeagrass Herbivory Levels Sustain Site- Fidelity in a Remnant Dugong PopulationPLoS ONE 10(10): e0141224. doi:10.1371/journal.pone.0141224Download
PDF, 624 KB
Seagrass Herbivory Levels Sustain Site-Fidelity in a Remnant Dugong Population
Herds of dugong, a largely tropical marine megaherbivore, are known to undertake long-dis- tance movements, sequentially overgrazing seagrass meadows in their path. Given their drastic declines in many regions, it is unclear whether at lower densities, their grazing is less intense, reducing their need to travel between meadows. We studied the effect of the feeding behaviour of a small dugong population in the Andaman and Nicobar archipelago, India to understand how small isolated populations graze seagrasses. In the seven years of our observation, all recorded dugongs travelled either solitarily or in pairs, and their use of seagrasses was limited to 8 meadows, some of which were persistently grazed. These meadows were relatively large, contiguous and dominated by short-lived seagrasses spe- cies. Dugongs consumed approximately 15% of meadow primary production, but there was a large variation (3–40% of total meadow production) in consumption patterns between meadows. The impact of herbivory was relatively high, with shoot densities c. 50% higher inside herbivore exclosures than in areas exposed to repeated grazing. Our results indicate that dugongs in the study area repeatedly graze the same meadows probably because the proportion of primary production consumed reduces shoot density to levels that are still above values that can trigger meadow abandonment. This ability of seagrasses to cope per- haps explains the long-term site fidelity shown by individual dugongs in these meadows. The fact that seagrass meadows in the archipelago are able to support dugong foraging requirements allows us to clearly identify locations where this remnant population persists, and where urgent management efforts can be directed.
- Journal Article2015Changes in the institution of family among the ChangpasLadakh Studies 32 • January 2015 • 4 - 17Download
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This paper focuses on the Changpas of Kargyam, with a specific focus on rules, norms, and patterns that govern the construction of social relationships in the family system and the factors that have influenced it. It provides an overview and description of these changes based on fieldwork carried out in 2010-12. Some of the important factors are the increased presence of Indian security forces after the 1962 Indo-China war, tourism, a new motor road, educational facilities and various government welfare schemes. Each of these factors has had an impact on the social structure of Changpa communities
- 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.