Niche dynamics and potential distribution of Butomus umbellatus under current and future climate scenarios in North America

Abstract

Predicting the potential distribution of invaders is informative for pre-emptive policy or management decisions and identifying suitable areas for establishment of new populations. Temporal projection of potential distributions is complicated by the magnitude and pace of changing climate, which could alter suitability under future conditions. The wetland invader, Butomus umbellatus is widespread in the northern US and southern Canada, but potential for invasion into new areas is unknown. We used environmental niche modeling to address our hypotheses for B. umbellatus: (1) a climatic niche shift has occurred between native and invasive ranges, (2) suitable areas in the invaded range have been colonized, and (3) climate suitability is likely to change in future climates. Environmental niche is highly conserved and stable (0.761) between ranges of B. umbellatus. Ensemble forecast revealed that nearly 60% of the invaded range is climatically suitable, including large areas in both the southern US and Alaska. Under future climates, there is a net decrease of suitable area, although two of three global circulation models predict range expansion of this species across gas emission scenarios. Given that the area is already invaded or at risk for future invasion, development of geographically adaptable long-term management strategies is prudent.