Anurans And Its Status In The Forest, Agricultural And Urban Ecosystemsin And Around Tumkur District, Karnataka

Anurans are popularly recognized for their bimodal life that generally includes an aquatic larval and terrestrial adult. They are pokilothermic organisms and the body temperature is strongly correlated with that of the environmental temperature. The most serious cause of amphibian and reptile decline in Europe is the loss of habitats (Ivelin 2011). The processes of habitat fragmentation and changes to the quality of habitat influenced the frog population across Melbourne (Kirsten 2006). Some local and regional factors influence the decline of frogs and toads in Michigan (Earl Werner et al. 2007). The Western Ghats is one of the 25 biodiversity hot spots in the world. Anurans are the integral components of many ecosystems and constitute the highest fraction of vertebrate biomass. They play an important role in acting as both predator and prey species and perform a key role in tropic dynamics (Odum 1956). Urban habitats are expanding throughout the world, and the processes of urbanization threaten the persistence of many plant and animal species. Amphibians, especially anurans, can inhabit many environments, from thick forest to small ponds. They adopt different physiological and behavioural traits. The decline in anuran population indicates ecosystem deterioration that might affect a wider spectrum of earth biological diversity. The anuran species richness is always correlated with the water body. The magnitude and direction of urban impacts on each species depends on that species life history attributes, sensitiveness to environmental disturbances, interspecies interactions and dispersal ability (Dickman 1987). The urbanization increases the density of human population and other infrastructures, which result in the displacement of flora and fauna. The diversity of fauna species exhibits varying responses to urbanization. The development rate and time to metamorphosis in Rhinella spinulosa is associated with pond duration (Marquez 2009). Concern about anuran declines has increased and it is now widely recognised that many species became extinct or decreased (Blaustein et al .1994). Conservation measures influenced the increase of the population size of Bufo calamita in Britain (John Buckley and Abstract: Lack of scientific data of Anuran populations in the Tumkur district, Karnataka, India, hampers in understanding the species richness. The present study of the assessment of Anuran population in the forest, agricultural and urban habitats of Tumkur district, from the year 2012 -13 revealed gradual differences in the distribution and size of these species. Adult frogs and toads were documented using Capture–Recapture and by Call survey methods. The larvae were counted using dip nets from the breeding sites. Seven Anuran species were recorded during the above period Duttaphrynus, Polypedates, Fejervarya, Hylo malabarica, Rana, Rachophorus and Kaloula taprobanica. The population size in the forest habitat was large compared to agricultural and urban habitats. The presence of anurans and habitat variables were subjected to ANOVA, Duncan Multiple regression and Karl Pearson correlation co-efficient test. Data analysis showed that anuran species in these habitats declined due to the consequences of anthropogenic activities. Hence there is an urgent need to develop conservation strategy for pool breeding and forest dwelling anurans.