- Journal Article2012Methodological, temporal and spatial factors affecting modelled occupancy of resident birds in the perennially cultivated landscape of Uttar Pradesh, IndiaLandscape Ecology 27: 59-71. doi:10.1007/s10980-011-9666-3.
Biodiversity persistence in non-woody tropical farmlands is poorly explored, and multispecies assessments with robust landscape-scale designs are sparse. Modeled species occupancy in agricultural mosaics is affected by multiple factors including survey methods (convenience-based versus systematic), landscape-scale agriculture-related variables, and extent of remnant habitat. Changes in seasonal crops can additionally alter landscape and habitat conditions thereby influencing species occupancy. We investigated how these factors affect modeled occupancy of 56 resident bird species using a landscape-scale multi-season occupancy framework across 24 intensively cultivated and human-dominated districts in Uttar Pradesh state, north India. Convenience-based roadside observations provided considerable differences in occupancy estimates and associations with remnant habitat and intensity of cultivation relative to systematic transect counts, and appeared to bias results to roadside conditions. Modeled occupancy of only open-area species improved with increasing intensity of cultivation, while remnant habitat improved modeled occupancy of scrubland, wetland and woodland species. Strong seasonal differences in occupancy were apparent for most species across all habitat guilds. Further habitat loss will be most detrimental to resident scrubland, wetland and woodland species. Uttar Pradesh’s agricultural landscape has a high conservation value, but will require a landscape-level approach to maintain the observed high species richness. Obtaining ecological information from unexplored landscapes using robust landscape-scale surveys offers substantial advantages to understand factors affecting species occupancy, and is necessary for efficient conservation planning.
- Popular Article2012Why we need to protect bat speciesThe Hindu in School, 6 June
- Popular Article2012Gowa of Ladakh!The Hindu in School, 11 July
- 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 Article2012The pigeon's passengersThe Hindu in School, 9 May
- 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
- Popular Article2012Trans-Himalaya: In the shadows of a giantCare4Nature
- Popular Article2012காக்கா…காக்க...(On Crows)புதிய தலைமுறை. 12ஜூலை 2012 Puthiya Thalaimurai. 12th July 2012
- Popular Article2012The talking treeThe Hindu in School, 5 December
- Journal Article2012Conservation of the Asian small-clawed otter (Aonyx cinereus) in human-modified landscapes, Western Ghats, IndiaTropical Conservation Science 5: 67-78.Download
PDF, 948 KB
Conservation in human-modified landscapes is important for riparian animals as their habitats extend linearly beyond adjoining protected areas. We examined occupancy and intensity of habitat use of Asian small-clawed otters in coffee and tea plantations and an adjoining protected area in the Western Ghats. We sampled 66 stream segments of 500 m length, using spraints as an indicator of habitat use. Several variables characterising the stream and shoreline were also measured. Occupancy, corrected for detection of spraints, was >0.75 in all three land use types, indicating widespread use of the riparian ecosystem in human-modified landscapes. Intensity of habitat use, however, was much lower in tea (2.08 spraints/500 m) and coffee (2.42) plantations than in the protected area (3.86). Using GLMs we identified the abundance of potential refuges (such as boulders and fallen trees), which was greater in the protected area, as the major factor influencing intensity of habitat use. Shoreline diversity, which was lowest in the tea plantation, might also be another factor. The retention of much of the riparian vegetation and the presence of forest fragments which provide refuges have led to wide occupancy of the tea and coffee plantations although with less intensive use. Sand mining, fishing and infrequent poaching might be other reasons for the relatively low use of human-modified landscape. This study highlights the need to retain remnant forests and riparian vegetation, and to control some human activities for integrated management of species like the small-clawed otter in both protected areas and adjoining human-modified habitats.
- Popular Article2012காட்டுக்குள்ளே ஷூட்டிங். (On impact of cinema shooting in wild habitats)புதிய தலைமுறை. 11அக்டோபர் 2012. Puthiya Thalaimurai. 11th October 2012.
- Popular Article2012புலியா?பறவையா?எதுஉசத்தி? (An article on another article written by Madhusudan Katti on Warbler vs Tigers)புதிய தலைமுறை. 9ஆகஸ்டு 2012. Puthiya Thalaimurai. 9th August 2012.
புலியா? பறவையா? எதுஉசத்தி?. காக்கைக்குருவிஎங்கள்ஜாதிதொடர்-5. புதியதலைமுறை. 9ஆகஸ்டு 2012. [Jeganathan, P. (2012).Puliya? Paravaiya? Ethu Usathi?. Kakkai Kuruvi Engal Jathi-Series, Article No.5 Puthiya Thalaimurai. 9th August 2012. (An article on another article written by Madhusudan Katti on Warbler vs Tigers)]
- Popular Article2012காட்டு நீரோடையின் மெல்லிசை மன்னன். (On Malabar Whistling Thrush)புதிய தலைமுறை. 2ஆகஸ்டு 2012 Puthiya Thalaimurai. 2nd August 2012
- 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 Article2012சின்னஞ்சிறுகுருவே…(On Ants)புதிய தலைமுறை. 26ஜூலை 2012. Puthiya Thalaimurai. 26th July 2012.
- Popular Article2012Expedition North AndamanThe Hindu in School, 12 September
- 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 Article2012The singing farmers of the forestThe Hindu in School, 21 November
- 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.
- Popular Article2012The feathered forestersSaevus 1(4, Sep/Oct): 28-33.