Kavita Isvaran

Adjunct Faculty, Other Initiatives

 dsc2380

Ph.D. in Ecology, University of Florida at Gainesville
M.Sc in Wildlife Sciences, Wildlife Institute of India

Kavita is Assistant Professor at the Centre for Ecological Sciences in the Indian Institute of Science, Bangalore.

She is interested in the ecology and evolution of behaviour and life histories, particularly in social and reproductive traits and in sexual selection. She is also interested in the consequences of evolved decisions for populations and communities; and in applying behavioural and evolutionary principles towards the conservation of species.

Projects

Grouper faceoff

Aggregating groupers

Documenting and protecting spawning aggregations in the Lakshadweep

Publications

  • Journal Article
    2017
    Alternative reproductive tactics and inverse size-assortment in a high-density fish spawning aggregation
    BMC Ecology, 17:10, DOI 10.1186/s12898-017-0120-5
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    PDF, 1.44 MB

    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.

  • Journal Article
    2015
    Looking beyond parks: the conservation value of unprotected areas for hornbills in Arunachal Pradesh, Eastern Himalaya
    Oryx, 49:303-311
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    PDF, 383 KB

    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 Article
    2015
    Reduced hornbill abundance associated with low seed arrival and altered recruitment in a hunted and logged tropical forest
    PLOSOne; 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.

  • Dataset
    2015
    Data of a study investigating impacts of hunting and logging on abundance of hornbills, dispersed seeds and recuits in north-east India
    http://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 Article
    2015
    Perceptions of priority issues in the conservation of biodiversity and ecosystems in India
    Varma, V, Ratnam, J, and many others, including, from NCF, Anand M Osuri, M D Madhusudan, Kavita Isvaran, Jagdish Krishnaswamy, Raman Kumar, Nisha Owen, Suhel Quader
    Biological Conservation, 187: 201-211
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    PDF, 886 KB

    Online link

    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 Article
    2013
    Antelope mating strategies facilitate invasion of grasslands by a woody weed.
    Shivani Jadeja, Soumya Prasad, Suhel Quader, Kavita Isvaran
    Oikos. 122(10): 1441-1452.
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    PDF, 357 KB

    Permanent link:
    http://doi.org/10.1111/j.1600-0706.2013.00320.x

    Intra and interspecific variation in frugivore behaviour can have important consequences for seed dispersal outcomes. However, most information comes from among-species comparisons, and within-species variation is relatively poorly understood. We examined how large intraspecific differences in the behaviour of a native disperser, blackbuck antelope Antilope cervicapra, influence dispersal of a woody invasive, Prosopis juliflora, in a grassland ecosystem. Blackbuck disperse P. juliflora seeds through their dung. In lekking blackbuck populations, males defend clustered or dispersed mating territories. Territorial male movement is restricted, and within their territories males defecate on dung-piles. In contrast, mixed-sex herds range over large areas and do not create dung-piles. We expected territorial males to shape seed dispersal patterns, and seed deposition and seedling recruitment to be spatially localized. Territorial males had a disproportionately large influence on seed dispersal. Adult males removed twice as much fruit as females, and seed arrival was disproportionately high on territories. Also, because lek-territories are clustered, seed arrival was spatially highly concentrated. Seedling recruitment was also substantially higher on territories compared with random sites, indicating that the local concentration of seeds created by territorial males continued into high local recruitment of seedlings. Territorial male behaviour may, thus, result in a distinct spatial pattern of invasion of grasslands by the woody P. juliflora. An ex situ experiment showed no beneficial effect of dung and a negative effect of light on seed germination. We conclude that large intraspecific behavioural differences within frugivore populations can result in significant variation in their effectiveness as seed dispersers. Mating strategies in a disperser could shape seed dispersal, seedling recruitment and potentially plant distribution patterns. These mating strategies may aid in the spread of invasives, such as P. juliflora, which could, in turn, negatively influence the behaviour and ecology of native dispersers.

  • Journal Article
    2009
    Effects of rodents on seed fates of hornbill-dispersed tree species in a tropical forest in north-east India.
    J. Tropical Ecology 25: 507-514.
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    PDF, 141 KB

  • Journal Article
    2004
    Nonlinear relationships and phylogenetically independent contrasts
    Suhel Quader, Kavita Isvaran, RE Hale, BG Miner, NE Seavy
    Journal of Evolutionary Biology 17 (3), 709-715
  • Journal Article
    2000
    Energetic dynamics and anuran breeding phenology: insights from a dynamic game
    SJ McCauley, SS Bouchard, BJ Farina, Kavita Isvaran, Suhel Quader, DW Wood, CM St Mary
    Behavioral Ecology 11 (4), 429-436

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