Ecological and anthropogenic covariates ... - GANGAPEDIA

variable data like river discharge, water depth, channel width, air and water
temperatures, shoreline substratum and presence of basking sites were recorded for
each of the 2.5 km segments at a scale of 0.5 km.
On the basis of the depth profile and shoreline substratum data, one-fifth of the study
area qualified as preferred gharial habitat. Availability of undisturbed basking sites in
conjunction with deep water segments emerged as the main variable explaining
gharial occurrence. All human activities appeared to negatively influence the use of
areas by gharials. Sand mining and cultivation around the banks negatively impacted
the use of such sites for basking. Gharials were seen less often and in fewer numbers
in areas where fishing was high. Similar results were seen with movement of people
and livestock along the river stretch. This study indicates the importance of inviolate
areas that satisfy the bio-physical requirements of the gharial.
I also describe a robust and easily replicable protocol for estimating gharial
population size using photo-capture of basking animals. I demonstrate the conceptual,
technical and logistic feasibility of applying photographic capture-recapture
techniques for estimating gharial abundance in the wild.
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