Weed risk assessment of Ambrosia psilostachya for its invasiveness and potential endangered areas in India

Abstract

The Weed risk assessment (WRA) is a science-based quarantine risk analysis tool for determining weedy / invasive potential of a plant species in establishing, spreading, and / or causing harm in a new area. Ambrosia psilostachya D.C., which found entry in India, is presently contained and eradication of the weed is in progress. It is essential to analyse its weedy or invasive potential, to predict its establishment in areas outside the delimited range. WRA has been carried out using the USDA-APHIS-PPQ1 model to evaluate the potential endangered areas in the country where the weed might establish. The analysis provides support to policy makers to negate the probable adverse effects in production systems and anthropogenic areas. The analysis indicated that A. psilostachya is a major-invader with an average to low uncertainity indices. Further, current global distribution of A. psilostachya indicates that the weed is relatively temperate with some subtropical influence. The geo-potential of A. psilostachya is evaluated based on joint distribution of climatic variables, viz., Plant cold hardiness zones, Köppen-Geiger climate classes and mean annual precipitation band. The agro climatic zones in North East and Central India appear to be most vulnerable for establishment of A. psilostachya. Policy recommendations based on the findings are proposed for developing biosecurity tools to safeguard the endangered area.