- Popular Article2012மரமும் மரியேனும். (On old trees and Marianne North)புதிய தலைமுறை. 18அக்டோபர் 2012. Puthiya Thalaimurai. 18th October 2012.
- Popular Article2012காட்டுக்குள்ளே ஷூட்டிங். (On impact of cinema shooting in wild habitats)புதிய தலைமுறை. 11அக்டோபர் 2012. Puthiya Thalaimurai. 11th October 2012.
- Popular Article2012அதிரப்பள்ளியும்அமிதாபச்சனும். (On Athirapalli Waterfalls,Dr. Amitha bachan’swork on Great Hornbills)புதிய தலைமுறை. 13 செப்டம்பர் 2012. Puthiya Thalaimurai. 13th September 2012.
அதிரப்பள்ளியும்அமிதாபச்சனும். காக்கைக்குருவிஎங்கள்ஜாதிதொடர்-10. புதியதலைமுறை. 13 செப்டம்பர் 2012.[Jeganathan, P. (2012).Athirapalliyum Amitha bachanum. Kakkai Kuruvi Engal Jathi-Series, ArticleNo.10Puthiya Thalaimurai. 13th September 2012. (On Athirapalli Waterfalls,Dr. Amitha bachan’swork on Great Hornbills)]
- Popular Article2012சின்னஞ்சிறுகுருவே…(On Ants)புதிய தலைமுறை. 26ஜூலை 2012. Puthiya Thalaimurai. 26th July 2012.
- Popular Article2012A home for the house sparrowThe Hindu in School, 18 April
Jeganathan, P. (2012). A home for the house sparrow. The Hindu in School, 18 April.
- Journal Article2012Optimizing individual identification and survey effort for photographic capture–recapture sampling of species with temporally variable morphological traitsAnimal Conservation 15(2): 174-183
Endangered, wide-ranging megafauna have many threats to contend with during their struggle for survival in an ever-increasing human dominance of the environment. Reliable monitoring of endangered large mammal populations is therefore a critical conservation requirement. Photographic capture–recapture (CR) techniques have opened up avenues for population monitoring of individually recognizable large mammal species. The efficient application of these techniques, however, can be constrained by challenges in reliably identifying individuals arising from the use of multiple, and potentially variable traits, as well as issues of temporal sampling of populations in the field. We address these key problems by describing an automated process of rapidly identifying individual Asian elephants (Elephas maximus) from photographs, and comparing resultant CR-based population parameter estimates with those obtained using supervised visual identification of individuals. In addition, we assess the temporal effort necessary for robust estimation of demographic parameters in our study population. Morphological traits that maintain constancy over time, including variations in tusk characteristics, and ear fold and lobe shape, proved the most reliable for individual identification and subsequent estimation of population parameters. The use of temporally variable traits contributed to high probabilities of misidentification and biased estimates of population size. We found a minimum of seven sampling occasions necessary for reliable population estimation. Our study contributes to design issues for CR studies by providing insights into optimality of sampling effort such that precision of parameter estimates are not compromised while minimizing survey costs. We demonstrate the importance of accurate individual identification in the context of such studies and recommend the use of fixed morphological traits as the optimal individual identification strategy for species where animals are distinguished on the basis of multiple attributes, including some that may be variable over time.
- Popular Article2012Expedition North AndamanThe Hindu in School, 12 September
- 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
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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 Article2012Standardizing the double-observer survey method for estimating mountain ungulate prey of the endangered snow leopardOecologia DOI: 10.1007/s00442-011-2237-0
- Popular Article2012The pigeon’s passengers.The Hindu Magazine, Sunday 6 May 2012, page 4.
Available here: http://www.thehindu.com/arts/magazine/article3387586.ece
Also here: http://www.thehindu.com/todays-paper/tp-in-school/the-pigeons-passengers/article3398790.ece
- Journal Article2012Impact of vehicular traffic on large mammal use of highway-edges in southern IndiaCurrent Science 102(7): 1047-1051Download
PDF, 166 KB
India’s phenomenal economic growth over the last decade has been accompanied by a much-needed expansion and improvement in transport and other infrastructure networks. While there are legally mandated assessments of the potential ecological impacts of such infrastructure projects prior to implementation, rarely are there post-implementation assessments of their real ecological impacts. In this communication, we present results of a preliminary study examining the impact of vehicular traffic on the usage of road edges by large mammals along a highway passing through Nagarahole Tiger Reserve, southern India. We estimated large mammal encounter rates at remotely triggered camera traps on two consecutive sections of the same highway – one closed to vehicular traffic and the other open to vehicles only during daytime. We observed lower encounter rates of chital, gaur and elephants at camera traps in the highway segment with higher vehicular traffic density, suggesting that these species avoided busy highways. Based on our findings, we emphasize the importance of continued ecological impact assessments of development projects to identify and mitigate unforeseen impacts. Further, an approach to development planning that integrates conservation concerns, especially where development projects coincide with ecologically critical areas, is urgently needed in India.
- Popular Article2012காக்கா…காக்க...(On Crows)புதிய தலைமுறை. 12ஜூலை 2012 Puthiya Thalaimurai. 12th July 2012
- Popular Article2012தட்டான் பார்க்கலாம் வாங்க (Lets watch Odonates)துளிர். ஜனவரி 2012. பக்கம் 16-18 / Thulir. Science monthly magazine for Kids. January Pp 7-10
தட்டான்பார்க்கலாம்வாங்க.துளிர். ஜனவரி 2012. பக்கம் 16-18. [Jeganathan, P. (2012).Thattan Pakkalam Vanga.Thulir. Science monthly magazine for Kids. January Pp 7-10(Lets watch Odonates)]
- Popular Article2012இடைவெளியும் இடையூறும் (Canopy gaps and obstacles: Canopy gaps above the forest roads and their impact on arboreal mammals of Western Ghats)Dinamani Tamil Newspaper. 29 January 2012.
இடைவெளியும் இடையூறும். தினமணி நாளிதழ் – கொண்டாட்டம் இணைப்பில். 29 ஜனவரி 2012. 3ம் பக்கம். [Jeganathan, P. (2012). Idaiveliyum Idayoorum. Dinamani- Tamil Newspaper. Date: 29th January (Canopy gaps and obstacles: Canopy gaps above the forest roads and their impact on arboreal mammals of Western Ghats) ]
Link for this article here.
- Popular Article2012என் பக்கத்து வீட்டு பழுப்புக் கீச்சான் (My friendly neighborhood Brown Shrike)தினமணி நாளிதழ் – கொண்டாட்டம் இணைப்பில். 26 பிப்ரவரி 2012. Dinamani- Tamil Newspaper. Date: 26thFebruary.
என்பக்கத்துவீட்டுபழுப்புக்கீச்சான்.தினமணிநாளிதழ் – கொண்டாட்டம்இணைப்பில். 26 பிப்ரவரி 2012. [Jeganathan, P. (2012)En pakkathu veetu pazuppu keechan.Dinamani- Tamil Newspaper. Date: 26thFebruary. (My friendly neighborhood Brown Shrike)]
- Popular Article2012Islands in peril: Conservation caveats.The Hindu Magazine, Sunday 26 February 2012, page 4.
- Report2012NCF Annual Report 2012
- Working Paper2012A Critique of the Nyamjang Chhu Hydro-electric power project Environmental Impact Assessment (EIA) and Environmental Management Plan (EMP)NCF Working Paper 2, Nature Conservation Foundation, Mysore.
- 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
- Journal Article2012To eat and not be eaten: modelling resources and safety in multi-species animal groups.PLoS ONE. 7(7): e42071.Download
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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.