Extraction of non-timber forest products in the forests of Biligiri Rangan hills, India. 4. Impact on floristic diversity and population structure in a thorn scrub forest

Abstract

Impact of extraction of non-timber forest products (NTFPs) was analyzed in a thorn scrub forest in Biligiri Rangaswamy Temple (BRT) wildlife sanctuary, India. Six species are most commonly extracted from BRT scrub for subsistence and income generation by an aboriginal tribe, the Soliga. Although the forest has been provided protection from indiscriminate felling since 1978 under a wildlife sanctuary cover, changes in vegetation structure are still occurring as a consequence of anthropogenic pressure in the form of extraction of fuelwood and other NTFPs. The results indicate that large woody species are being replaced by small woody species. The population structure also is becoming increasingly skewed to the smaller size classes due to extraction-bound mortality of the individuals, particularly those>7 cm dbh and above. The data suggest that the scrub community itself may be a manifestation of long persisting anthropogenic pressure in the form of extraction of a variety of forest products, and it currently represents a downward transition from a deciduous forest to a shrub thicket.