Ecological impacts of prescribed burning in Corbett Tiger Reserve, Uttar Pradesh

Abstract

This study was aimed at studying the ecological impacts of prescribed burning by evaluating the current practices of burning being carried out in a typical grassland habitat in Corbett Tiger Reserve . The study extended from November 1996 to April 1997. Twenty four experimental plots were laid to study the differences in soil and vegetation characteristics, with respect to burnt and unburnt areas in short (Arundinella and Vetiveria type) grasslands and tall (Saccharum-Themeda type) grasslands. The main objectives were to determine the impacts of prescribed burning on soil and vegetation characteristics,, distribution of animal and birds and to evolve spatial strategies for the management of Hog deer( Cervus porcinus) populations using Remote Sensing and Geographic Information systems. —T-tests and AN OVA (analysis of variance) were applied on the various soil and vegetation parameters to test the differences between the burnt and unburnt areas. Short grasslands showed significant differences in soil available phosphorus, above ground biomass, crude protein, percentage fibre, ash, elemental potassium and sodium. The general increase in the soil available phosphorus, above ground biomass, crude protein and the decrease in the levels of percentage fibre, ash , elemental potassium and sodium in the short grassland burnt areas can be generally attributed to the removal of litter and the addition of ash which recycles the minerals back into the system. Tall grasslands showed significant differences in case of soil available potassium and grass percentage fibre. Both the parameters decreased in case of the burnt areas. I he tall grasslands are tussock- forming perennial species which do not get burnt completely. There is not much removal of litter which perhaps hampers the growth of the new sprouts. Samples collected from burnt and repeatedly clipped areas were tested for crude protein, percentage fibre, ash and lignin. They showed significant differences in case of percentage fibre. The fibre being the maximum in. case of these areas. Below ground biomass did not show any difference between the burnt and unburnt areas in short and tall grasslands . The area has had a long fire history and the below ground biomass has perhaps stabilised over the years and hence cannot be detected in such a short term study. Direct (road transects) and indirect (pellets) evidences were used to determine the animal and bird distribution with respect to the burning regime. Programme DISTANCE was used to estimate the animal densities while Menhinick's Index was used to calculate the bird species richness , before and after the date of prescribed burning. The animal densities and birds species richness increased after burning, but this could not be fully attributed to the burning regime. Other parameters such as change of seasons, also need to be taken into consideration . Finally, hog deer suitability map was generated using ground data for various ecological parameters and remote sensing data which were overlaid with the help of Geographic Information system . A burning regime separated on a temporal and spatial scale is required for sustaining hog deer populations in Corbett Tiger Reserve.