Spatio‐temporal partitioning between two sympatric crocodilians (Gavialis gangeticus & Crocodylus palustris) in Katarniaghat Wildlife Sanctuary, India

Abstract

Abstract Gavialis gangeticus (gharial) and Crocodylus palustris (mugger) have a sympatric distribution in the northern and eastern river systems of India, but no single extensive study exists on the mechanisms favouring the coexistence of these species, or explains whether mugger have a detrimental effect on gharial. For the effective conservation of gharial within its natural range it is very important to study the impacts of various habitat attributes on its distribution. This study was undertaken to investigate how resources are shared by the species, and the key requirements that lead to the selection of a particular basking and nesting site. Results indicate that the habitat variables that lead to the selection of basking sites differed between the species, and varied between seasons. In winter, habitat variables responsible for the selection of a basking site by gharial were slope, height, soil moisture, presence of sandbar, distance to water, and current land‐use pattern, whereas for mugger the relevant habitat variables were slope and height only. During the summer, habitat use, depth gradient, and distance to water were factors for mugger, whereas slope, height, soil moisture, the presence of a sandbar, water depth gradient, and distance to water were important habitat attributes for gharial. Gharial and mugger had a totally different preference of habitat attributes for nest‐site selection. Gharial laid eggs near water and only in sandy soil, whereas mugger nests were found far from a water source and no substrate preference was shown. Effective habitat management is imperative for the conservation of gharial. Restocking with individuals bred in captivity might increase the population in the short term, but in order to create a viable population, long‐term habitat conservation plans are required.