Niche shifts undermine the prediction performance of species distribution models: estimating potentially suitable areas for Myriophyllum aquaticum at the global scale

Invasive alien species (IAS) can undergo niche shifts upon establishment in novel environments that differ from their native ranges. The validity of species distribution models (SDMs) depends on the underlying assumption of niche conservatism that IAS can only successfully establish populations in environments that closely resemble their native regions. This has led us to examine how ecologists can use SDMs to predict potentially suitable areas for invasive alien species in the context of niche shifts. Here, we compared the niches of Myriophyllum aquaticum in its native and invasive ranges to quantify the shifts that occurred during its global invasion using the centroid shift, overlap, unfilling, and expansion (COUE) framework. We also aimed to investigate the effects of niche shift on the prediction performance of SDMs. The SDMs were calibrated using data from three different sources: the native range, the invasive range, and a combination of both. The study examined how these different data sources influenced the accuracy of the SDM predictions. The findings indicated the niche expansion between the invasive and native ranges. The invasive (based on the occurrence data of invasive ranges) and global (based on the occurrence data of global ranges) models underestimated the potentially suitable areas (PSAs) of M. aquaticum in the Southern Hemisphere. The native model (based on the occurrence data of native ranges) underestimated the PSAs of M. aquaticum in the Northern Hemisphere. We combined the results of the invasive and native range models to estimate the global PSAs of M. aquaticum, addressing the predictive limitations of a single model in a complementary form. The PSAs of M. aquaticum were predominantly distributed in eastern Asia, western Europe, southern North America, southern South America, and southern Oceania and expanded into higher latitudes under future climate scenarios. Our study has applied a simple yet effective method for predicting the global PSAs of M. aquaticum given niche shifts, which confirmed the observations of the previous studies and provided a theoretical basis for the early warning, prevention and control of M. aquaticum.