EFFECT OF TOPOGRAPHY ON THE DISTRIBUTION OF TROPICAL MONTANE FOREST FRAGMENTS: A PREDICTIVE MODELLING APPROACH

Abstract

Topography and elevation influence vegetation across biomes in terms of species composition and assemblages. Topographical variables have been used to determine species richness, regional biodiversity patterns, forest health, species distributions and gradients of exotic species. Within the Western Ghats of India, the potential of geographic information systems and remotely-sensed data in characterising tropical montane forests (locally known as sholas) has been investigated. In this study, the influence of topographical variables in determining the presence of shola fragments was tested. A multiple logistic regression approach was used to predict presence or absence of insular fragments in the matrix of grasslands using elevation data. We observed that topographical variables significantly predicted whether the vegetation type was shola or non-shola. Of all the variables, aspect (as quantified in eastness and northness) strongly determined the presence of shola fragments whereas wetness index and curvature of slope influenced the results to a lesser extent. Positive correlation of wetness index with the presence of shola fragments suggested the maintenance of shola by hydrological regulation.