Predicting the geographical distribution of an invasive species (Chromolaena odorata L. (King) & H.E. Robins) in the Indian subcontinent under climate change scenarios.

Abstract

Abstract This chapter describes the application of ecological niche modelling (ENM) in depicting the current and future geographical distribution of C. odorata based on its ecological niche using 458 records collected for native range distributions in North and South America. The predictive capacity of the niche model transferred to the Indian subcontinent was evaluated by assessing the probability level at which the model was successful in correctly predicting the current distributional range of the selected species. The model calibration test for C. odorata in its native range yielded good results. Among the input environmental parameters, the climatic variables were more sensitive and contributed 62% to the structure of the modelled ecological niche of the species compared with the physiographic variables, which contributed only 38%. The thermal variables, i.e. mean annual temperature (20.4%) and mean annual minimum temperature (29%), governed the macro-scale niche characteristic. The niche model showed that the response of the species peaked at a mean annual temperature range of 15-25°C, and there was a consistent increase in responsiveness with an increase in mean annual minimum temperature. The niche model generated using native range distribution predicted most of the validation points in the northern part of the Indian subcontinent at >70% probability. However, some locations in central and southern India were predicted at a probability level of <30%. The areas suitable for C. odorata include Jammu and Kashmir, Himachal Pradesh, Uttarakhand and West Bengal in the central Himalayas, and Arunachal Pradesh, Sikkim, Meghalaya, Nagaland, Mizoram, Manipur and Assam in the eastern Himalayas. The model also shows environmental suitability in Gujarat, Maharashtra, Karnataka, Kerala, Tamil Nadu, Andhra Pradesh and Orissa. Areas adjacent to the Indian sub-region showing high suitability for the species include Nepal, Myanmar and Pakistan. The Western and Eastern Ghats, the central Himalayan region, and the northeastern part of the Indian subcontinent are shown to be more susceptible to invasion by C. odorata under current climatic conditions and predicted future climate warming.