- Report2018Understanding impacts of hornbill loss on plants.Final report submitted to Arunachal Pradesh Forest Department, Itanagar, Arunachal Pradesh towards completion of the research project titled “Understanding Impacts of Hornbill Loss on Plants”.Download
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While large avian frugivores are known to be key dispersers for large-seeded plants, their role in the wider plant-disperser networks is still poorly known. In this study, we evaluate the role of large avian frugivores in plant-disperser communities using network and seed dispersal effectiveness approaches in a tropical forest site in north-east India. We systematically-collected tree watch data from 46 plant species, representing 85 percent of typically bird-dispersed plant species, spanning over 2055 h. We found that the plant-disperser community was modular with a distinct community of large-sized seed plants and frugivores. While intermediate-sized birds such as barbets and bulbuls were the most connected, large-sized dispersers such as hornbills and Imperial-pigeons were moderately well-connected. Imperial-pigeons consistently fed on large-sized fruits, highlighting their importance for dispersal of large-seeded plants. In addition to frugivore-fruit size matching, frugivore dietary choices might play an important role in governing the organization of modules. There was a gradient in qualitative and quantitative roles played by different dispersers, with hornbills removing significantly larger number of fruits and consistently swallowing larger proportions of fruits as compared to other avian groups. Under simulated extinction scenarios, observed networks were far less resilient to disperser loss along a gradient of body size from large to small as compared to extinctions that were random or based on rarity. Given the paucity of information on plant-disperser networks from the South Asian region and reported local extinctions of large frugivores like hornbills, this study is important in highlighting that loss of large avian frugivores might have irreplaceable quantitative and qualitative damages to plant communities.
- Journal Article2018eBird in Asia: standardised tools for birdwatchersBirdingASIA, 29:105-108
- Journal Article2018Responses of interspecific associations in mixed-species bird flocks to selective loggingJournal of Applied Ecology, 55: 1637-1646.
- 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
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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 Article2017Commensal in conflict: Livestock depredation patterns by free-ranging domestic dogs in the Upper Spiti Landscape, Himachal Pradesh, IndiaAmbio: doi:10.1007/s13280-016-0858-6Download
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In human-populated landscapes worldwide, domestic dogs (Canis lupus familiaris) are the most abundant terrestrial carnivore. Although dogs have been used for the protection of livestock from wild carnivores, they have also been implicated as predators of livestock. We used a combination of methods (field surveys, interview surveys, and data from secondary sources) to examine the patterns and factors driving livestock depredation by free-ranging dogs, as well as economic losses to local communities in a Trans-Himalayan agro-pastoralist landscape in India. Our results show that livestock abundance was a better predictor of depredation in the villages than local dog abundance. Dogs mainly killed small-bodied livestock and sheep were the most selected prey. Dogs were responsible for the majority of livestock losses, with losses being comparable to that by snow leopards. This high level of conflict may disrupt community benefits from conservation programs and potentially undermine the conservation efforts in the region through a range of cascading effects.
- Journal Article2017Alternative reproductive tactics and inverse size-assortment in a high-density fish spawning aggregationBMC Ecology, 17:10, DOI 10.1186/s12898-017-0120-5Download
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Mating successfully at high densities often requires species to employ unusual reproductive tactics. We report unique courtship behaviours in an un shed, high-density spawning aggregation of squaretail groupers (Plectropomus areolatus) that are potentially associated with alternative reproductive tactics (ARTs). Aggregating males are typically known to court females in small territories (pair courtship), which is often associated with a pair-spawning tactic. However, we also observed the largest males simultaneously courting several females in mid-water shoals – a unique, high-cost-high-benefit courtship tactic which appears to result in a novel school-spawning tactic. Counter-intuitively we observed an inverse size- assortment in individuals–large males courted smaller females and vice-a-versa, likely linked to different pay- offs with competitive ability and local mate density. These unique, high-density behaviours are threatened to be lost, with increasing commercial fishing pressures on the P. areolatus aggregation.
- Popular Article2017Life of PineThe Hindu in School, 8 March
- Journal Article2017From intent to action: A case study for the expansion of tiger conservation from southern IndiaGlobal Ecology and Conservation, 9: 11–20Download
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To conserve a large, wide-ranging carnivore like the tiger, it is critical not only to maintain populations at key habitat sites, but also to enable the persistence of the species across much larger landscapes. To do this, it is important to establish well-linked habitat networks where sites for survival and reproduction of tigers are complemented by opportunities for dispersal and colonization. On the ground, expanding protection to areas with a potential for tiger recovery still remains the means of operationalizing the landscape approach. Yet, while the gazetting of protected areas is necessary to enable this, it is not sufficient. It is essential to benchmark and monitor the process by which establishment of protected areas must necessarily be followed by management changes that enable a recovery of tigers, their prey and their habitats. In this paper, we report a case study from the Cauvery and Malai Mahadeshwara Hills Wildlife Sanctuaries of southern India, where we document the infrastructural and institutional changes that ensued after an unprecedented expansion of protected areas in this landscape. Further, we establish ecological benchmarks of the abundance and distribution of tigers, the relative abundance of their prey, and the status of their habitats, against which the recovery of tigers in this area of vast conservation potential may be assessed over time.
- Popular Article2017Defenders of the moundThe Hindu in School, 22 March
- Report2017Hornbill Watch Report June 2014 to February 2017June 2017, www.hornbills.in
- Journal Article2017Coping with catastrophe: foraging plasticity enables a benthic predator to survive in rapidly degrading coral reefsAnimal Behaviour, Vol 131: 13-22. http://dx.doi.org/10.1016/j.anbehav.2017.07.010Download
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Human-induced rapid environmental change (HIREC) disproportionately affects species with specialist traits and long generation times. By circumventing prolonged evolutionary processes, behavioural plasticity is critical in allowing species to cope with rapid environmental changes within their lifetimes. Coral reefs have faced multiple mass mortality events of corals related to climate change in the last two decades. The consequent loss of structural complexity adversely impacts long-lived, structure-dependent fish predators. We attempted to determine how well a guild of groupers (Pisces: Epinephelidae) copes with rapid structural change in the lightly fished Lakshadweep Archipelago, Indian Ocean. Of the 15 species, territorial and site-attached groupers declined exponentially with decreasing structural complexity, while widely ranging species showed no change. However, one site-attached species, the peacock grouper, Cephalopholis argus, maintained high densities across the structural gradient. We explored the mechanisms this species employs to cope with declining habitat structure. Our observations indicate that both a potential release from specialist competitors and plasticity in foraging behaviour (foraging territory size, diet and foraging mode) appeared to favour the peacock grouper's survival in sites of high and low structure. While specialist competitors dropped out of the assemblage, the foraging territory size of peacock groupers increased exponentially with structural decline, but remained constant and compact (50 m2) above a threshold of structural complexity (corresponding to a canopy height of 60 cm). Interestingly, despite significant differences in prey density in sites of high and low structure, gut content and stable isotope analyses indicated that peacock groupers maintained a specialized dietary niche. In-water behavioural observations suggested that diet specialization was maintained by switching foraging modes from a structure-dependent ‘ambush’ to a structure-independent ‘widely foraging’ mode. The remarkable foraging plasticity of species such as the peacock grouper will become increasingly critical in separating winners from losers and may help preserve specialist ecosystem functions as habitats collapse as a result of climate change.
- Book2017Birds of the Andaman & Nicobar Islands: A pocket guide to 139 birds of the islands
- Book2017Birds of Karnataka (Kannada) - pocket guide
- Journal Article2017Snow Leopard, Ecology and Conservation Issues in IndiaResonance, Indian Academy of Sciences, DOI 10.1007/s12045-017-0511-0Download
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Snow leopard, an elusive mammal species of the cat family, is the top-predator of the Central and South Asian, highaltitude ecosystem. Snow leopards occur at low densities across the Central Asian mountains and the Indian Himalayan region. Owing to their secretive nature and inaccessible habitat, little is known about its ecology and distribution. Due to its endangered status and high aesthetic value, the snow leopard is considered as an ‘umbrella species’ for wildlife conservation in the Indian Himalayas. This article summarizes the current knowledge on snow leopard ecology and conservation issues in the Indian context.
- Dataset2017Data from: Plant-disperser mutualisms in a semi-arid habitat invaded by Lantana camara L. Plant EcologyData Dryad. http://dx.doi.org/10.5061/dryad.gc6dm
- Dataset2017Playing it safe? behavioural responses of mosquito larvae encountering a fish predator. Ethology Ecology & EvolutionData Dryad. http://dx.doi.org/10.5061/dryad.mc132
- Journal Article2017Plant-disperser mutualisms in a semi-arid habitat invaded by Lantana camara L.Plant Ecology 218 (8): 935-946
Dispersal is an important ecological process that affects plant population structure and community composition. Invasive plants with fleshy fruits rapidly form associations with native and invasive dispersers, and may affect existing native plant-disperser associations. We asked whether frugivore visitation rate and fruit removal was associated with plant characteristics in a community of fleshy-fruited plants and whether an invasive plant receives more visitation and greater fruit removal than native plants in a semi-arid habitat of Andhra Pradesh, India. Tree-watches were undertaken at individuals of nine native and one invasive shrub species to assess the identity, number and fruit removal by avian frugivores. Network analyses and generalised linear mixed-effects models were used to understand species and community-level patterns. All plants received most number of visits from abundant, generalist avian frugivores. Number of frugivore visits and time spent by frugivores at individual plants was positively associated with fruit crop size, while fruit removal was positively associated with number of frugivore visits and their mean foraging time at individual plants. The invasive shrub, Lantana camara L. (Lantana), had lower average frugivore visit rate than the community of fleshy-fruited plants and received similar average frugivore visits but greater average per-hour fruit removal than two other concurrently fruiting native species. Based on the results of our study, we infer that there is little evidence of competition between native plants and Lantana for the dispersal services of native frugivores and that more data are required to assess the nature of these interactions over the long term. We speculate that plant associations with generalist frugivores may increase the functional redundancy of this frugivory network, buffering it against loss of participating species.
- Journal Article2017The database of the PREDICTS (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems) projectEcology and Evolution, Volume 7, Issue 1 Pages: 145–188
The PREDICTS project—Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)—has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used this evidence base to develop global and regional statistical models of how local biodiversity responds to these measures. We describe and make freely available this 2016 release of the database, containing more than 3.2 million records sampled at over 26,000 locations and representing over 47,000 species. We outline how the database can help in answering a range of questions in ecology and conservation biology. To our knowledge, this is the largest and most geographically and taxonomically representative database of spatial comparisons of biodiversity that has been collated to date; it will be useful to researchers and international efforts wishing to model and understand the global status of biodiversity.