Climate Change and More Disturbed Land-Use Types will Further the Invasion of a Non-Native Annual Grass, Ventenata Dubia

Abstract Many land uses are highly prone to invasion of new non-native plant species under changing climate. Identification of suitable habitat for invasive weeds and their projected infestation extent across different land use cover types under a changing climate is crucial for the broad management goals of prevention, detection, and rapid response. In this study, we adopted an ensemble approach of species distribution models to project potential habitat of the invasive annual grass, Ventenata dubia, along the road corridor of Gallatin county, Montana, USA, under current and future climates. The model prediction of V. dubia habitat was excellent. The climate predictors most correlated with V. dubia occurrence were precipitation, potential evapo-transpiration, relative humidity, vapor pressure deficit, and solar radiation for months during the growing season, and fall germination. The model projected 1,945 and 7,374 km2 under RCP4.5, and 2,306 and 11,050 km2 for road corridors and Gallatin county, respectively. We found that the projected increases in V. dubia infestations were highest for road corridors (239% under RCP4.5 and 302% under RCP8.5) compared to that of Gallatin County (127% under RCP4.5 and 241% under RCP8.5). Among the land class types, the model projected greatest expansion of V. dubia cover across agriculture land with 425% and 484% and grassland with 278% and 442% increase under RCP4.5 and RCP8.5, respectively. We conclude that V. dubia with a short history of invasion is expanding at an alarming rate challenging the status quo and requires greater investment in detection and monitoring to prevent further expansion.