Development of Methodologies and Models
WCS – India was the first in the country to put in place a long-term monitoring program for ungulates and other herbivores, using line transect sampling in 1989. The study design, field protocols and analytical methods have all been continually refined since then. Camera trap sampling of tigers in a capture recapture framework was developed in Nagarahole in the early 1990s, and has since been adopted worldwide and used for a large variety of species with individually identifiable markings.
WCS – India has led and has been closely involved with the development of technologies, field protocols and analytical approaches related to camera trap-based density estimation, including field sampling schedules. We have developed a software program called ExtractCompare that allows speedy and reliable identification of tigers from camera trap photographs. More recently, we have developed a freely downloadable software package called SPACECAP. This new approach is more flexible than conventional capture recapture models and is less prone to biases arising from various factors.
WCS – India has also been closely associated with the development of approaches to investigating the spatial distribution of species when they are not always detected. One of the earliest occupancy models was developed by our program in 2002 and we have actively refined and extended the approach. This includes developing an analytical approach for situations when sampling for species’ presence carried out along roads and trails, and the application of recently developed abundance-induced heterogeneity models to estimate ungulate densities in forest areas.
All our methodological developments have surpassed the international scientific peer-review process. We also ensure that these methods are accessible to field biologists across the world by publishing more than 150 scientific papers, technical manuals and instructional DVDs, as well as through courses and workshops conducted by WCS – India staff.