Abstract

Global biodiversity is disappearing at an alarming rate. Habitat loss, fragmentation, habitat degradation, direct pressures like hunting and other extractive human uses are all contributing to the loss of biodiversity, which in turn are leading to the loss of vital ecosystem services. Different conservation strategies have been proposed for arresting this loss of biodiversity in tropical countries, through establishment of protected areas of various types. In India, a model based on ‘wildlife preservation’ under state ownership of protected areas is predominant. However, alternative models based on community ownership and sustainable resource use by local people are also being advocated for preserving biodiversity. However, a practical problem in evaluating such broad, generic alternative models of wildlife is that these are not locally context-specific or sufficiently evidence-based. We examined human impacts on different forms of biodiversity under different levels of local access, degree of state protection and legal and illegal resource extraction regimes in a conservation landscape in Nagarahole, southern India. We applied current and rigorous sampling, modeling and estimation approaches to assess the status of three components of biodiversity, namely plants, birds and mammals, across three ecologically similar areas that differed only in terms of access and human impact characteristics. Different levels of human disturbance and environmental variables altered species composition, richness, diversity and abundance of plants, birds and mammals. These impacts were generally negative on a wide range of taxonomic groups. Estimated values of species richness and abundance of plants and birds were higher for highly protected and moderately protected areas compared to least protected areas. Strict protected areas were particularly important for galliformes and omnivores, while moderately protected areas were important for insectivores, granivores and insecti-frugivores, amongst birds. We also showed that the loss of bird guilds have serious consequences on seed dispersal, forest growth and regeneration. Abundance estimates for terrestrial mammals were substantially higher for highly protected and moderately protected areas. These differences were particularly evident for arboreal mammals. Decline in mammalian abundance recorded in the present study are likely to have cascading effects on overall structure and functioning of these forests. Through these results, we discuss the relevance of the ‘wildlife preservation’ approach to conserving varied forms of biodiversity particularly within human-dominated landscapes of India.