Distribution of some obnoxious weeds in north-western Ghats of India

Abstract

Flora and fauna of Western Ghats, a biodiversity hot spot are under major threat due to various factors. Invasion of exotic species has been considered as one of the major threat in the area. In the present study, potential distribution of three obnoxious weeds, viz. Chromolaena odorata, Lantana camara and Parthenium hysterophorus was modeled using 32 environmental variables and MAXENT modeller. These three species showed distinct potential distribution patterns with only slight overlap between C. odorata and L. camara, and between L. camara and P. hysterophorus. Overlap of the former pair was seen mostly along the wet western slopes of Western Ghats, and latter along the eastern, rain shade dry areas. The environmental variables that contributed to the model showed that it was basically precipitation and temperature seasonality that defined their distribution. It was interpreted that the weeds might have adapted to different sets of environmental conditions throughout their distributional range; and hence, the variables operating in the study area contributing to the model may not be useful in predicting their presence elsewhere. It is concluded that to understand the full adaptability of these weeds, environmental variables can be studied at local levels and the results compiled for larger areas to get the full spectrum.