Spread Risk Assessment of Invasive Axis Deer using Bioclimatic Niche Models

Abstract

Ecological niche models (ENM) calibrated with data from native and invaded ranges are useful tools to manage biological invasions and can be challenged by niche shifts and non-equilibrium processes. We modeled the extent of the potential invasion by the axis deer (Axis axis) worldwide, testing the reciprocal hypotheses of niche conservatism and shift. We quantified niche overlap on the multivariate climatic space and modeled climatic realized niche based on detailed field information. We showed that the axis deer shifted its realized niche after the invasion. We rejected the niche equivalency hypothesis. Most of the climatic niche available in invaded areas is contained in the native climatic niche. Non-equilibrium between native and invasive niches of the axis deer was confirmed due to a large number of unfilled areas in invaded regions. Our projections predict that the most significant regions suitable for the axis deer are located in tropical and subtropical climates around the equator and the southern hemisphere, mostly in the Neotropics.