- Popular Article2012The sheep that isn'tThe Hindu in School, 20 June
- Popular Article2012Twinkle, twinkle, little batThe Hindu in School 2 May
- Popular Article2012Expedition North AndamanThe Hindu in School, 12 September
- Journal Article2012Streamside amphibian communities in plantations and a rainforest fragment in the Anamalai hills, IndiaJournal of Threatened Taxa 4: 2849–2856.Download
PDF, 3.44 MB
Stream amphibian communities, occupying a sensitive environment, are often useful indicators of effects of adjoining land uses. We compared abundance and community composition of anuran amphibians along streams in tea monoculture, shade coffee plantation, and a rainforest fragment in Old Valparai area of the Anamalai hills. Overall species density and rarefaction species richness was the highest in rainforest fragment and did not vary between the coffee and tea land uses. Densities of certain taxa, and consequently community composition, varied significantly among the land uses, being greater between rainforest fragment and tea monoculture with shade coffee being intermediate. Observed changes are probably related to streamside alteration due to land use, suggesting the need to retain shade tree cover and remnant riparian rainforest vegetation as buffers along streams.
- Popular Article2012Of tamarind and toleranceThe Hindu Magazine, 17 June 2012, page 4.
Link to this article here.
- Journal Article2012Averting biodiversity collapse in tropical forest protected areas.Nature 489: 290-294.
- Journal Article2012To eat and not be eaten: modelling resources and safety in multi-species animal groups.PLoS ONE. 7(7): e42071.Download
PDF, 291 KB
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 Article2012Structure and dynamics of South East Indian seagrass meadows across a sediment gradientAquatic Botany, 98 (1): 34-39Download
PDF, 321 KB
In this study we examine the influence of non-monsoon sediment arrival on the high-diversity SE Indian seagrass meadows of the Palk Bay and the Gulf of Mannar. We used a gradient-based approach to examine the influence of increasing sediment loads on species composition and shoot density. In addition, for the ubiquitous seagrass (Cymodocea serrulata), we tested the influence of sediment on its biomass and productivity. We identified three sites in Palk Bay and four sites in Gulf of Mannar (SE India) along a gradient of sediment input. At each of the seven locations, sediment traps were deployed to measure sedimentation rates. Nine seagrass cores were taken systematically along 50 m transects at a constant sub-tidal depth to measure shoot density and biomass. A few shoots of C. serrulata were marked to estimate the above ground seagrass growth rate. Our results indicate that sedimentation rates that ranged from 8.6 to 62.4 mg DW cm−2 d−1 could not explain species composition of the meadow or shoot density of the observed species. C. serrulata was, by far, the most abundant species and present in all sediment condi- tions. Sedimentation rates did not alter shoot elongation rates in C. serrulata, ranging from 1.54 ± 0.29 SD to 0.25 ± 0.02 SD cm d−1 , but in contrast, increased vertical rhizome elongation rate. This increase was reflected in an increase in below ground biomass along the sediment gradient (R2 = 0.582, p = 0.01). C. serrulata appears to be able to adapt to the sediment dynamics in this area by allocating resources to rhizomes and roots to counteract burial and stabilizing sediments. Given that siltation is one of the most important threats to seagrass meadows, understanding the species-specific adaptive mechanisms of seagrass species in these high-sediment, high diversity South Asian meadows is an important first step in ensuring their long-term survival and functioning
- Popular Article2012Hornbills: farmers of our forestsThe Hindu in School, 4 April
- 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
PDF, 216 KB
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
PDF, 345 KB
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.
- Report2012Protecting a hornbill haven: a community-run conservation initiative around Pakke Tiger ReserveHNAP Report for 2012Download
PDF, 2.11 MB
2012 Report for Hornbill Nest Adoption Program
- Thesis2012Primate on the edge: Ecology and Conservation of Primate Assemblages in the Fragmented Lowland Rainforests of the Upper Brahmaputra Valley, Northeastern IndiaPhD Thesis submitted to Manipal University, Manipal, Karnataka
- Popular Article2012A problem landscape in the Western GhatsHornbill, April-June, 2012 : 4-8
- Journal Article2012Socio-economic drivers of Forest Cover Change in Assam: A Historical PerspectiveEconomic and Political Weekly 47(5): 64-72Download
PDF, 721 KB
This article analyses the historical context of forest cover change in the upper Brahmaputra Valley of Assam during the precolonial, colonial and the postcolonial periods, locating these changes within the political economy and demographic milieu of each regime.In the current context of rising populations linked to immigration from neighbouring regions, dwindling share of agriculture in the state’s gross domestic product, and recent incentives to small tea growers in risk-prone agricultural landscapes, serious challenges remain to securing forests in this region. Empowering local communities and institutions, understanding tea plantation dynamics and managing the causes and consequences of recent demographic change are crucial to the conservation of forests there.
- Popular Article2012Trans-Himalaya: In the shadows of a giantCare4Nature
- Report2012NCF Annual Report 2012
- Journal Article2012Distance-related thresholds and influence of the 2004 tsunami on damage and recovery patterns of coral reefs in the Nicobar IslandsCurrent Science 102:1199–1205
The earthquake and tsunami of 2004 resulted in the devastation of marine and coastal ecosystems across the Indian Ocean. However, without adequate baseline information it has been difficult to properly gauge its full impact. The reefs of the Nicobar Islands in the Bay of Bengal lie on a path that ranges from 190 to 500 km from Banda Aceh, the epicentre of the 2004 tsunami. In 2008, we recorded benthic damage as a result of the tsunami to reefs off 14 Nicobar Islands across a gradient of distance from the epicentre. A clear pattern was observed in the demographic structure of the most abundant coral genera, Acropora and Porites across the distance gradient. Significantly, for the largest coral individuals of both genera (> 50 cm diameter), there were distinct threshold effects – their abundance declining dramatically in reefs closer than 350 km from the epicentre. Corals between 20 and 50 cm diameter also increased with distance from the epicentre, but in a more linear fashion. Smaller size classes either showed no apparent trend (Acropora) or decreased linearly (Porites) with distance. These gen- era represent very different life-history strategies: Acropora is fast-growing and highly susceptible to a range of disturbances, while Porites typically grows slowly but is resistant to disturbance. The fact that both genera showed similar thresholds indicates that, close to the epicentre, the impact of the earthquake and tsunami was large enough to override any species- specific resistance. Also, algal cover was also much higher than at locations further north, linked to higher coral mortality at these locations. However, the fact that smaller size class coral individuals were rela- tively abundant and even increased close to the ep centre indicates possible paths of reef recovery after the catastrophe.
- Popular Article2012A thousand leopards in the SeaThe Hindu in School, 29 September
- Popular Article2012Dugongs, mermaids of the seaThe Hindu in School, 26 September