Current and Future Climate Models for Ten Remaining Species of Achatinella to Inform Potential Locations of Ex Situ Predator-Free Exclosures

Abstract

Ectotherms are particularly sensitive to drought and extreme temperatures and may act as bellwethers of climate change, but declines are often attributed to other threats. As a result, the threat of climate change may be under-estimated. The decline of Hawaiian tree snails in the genus Achatinella has largely been attributed to over-collection, habitat loss, and introduced predators. Currently, most species remain only in captive rearing facilities or predator-free exclosures, following recent sharp declines and population “blink-outs”. In this study, I developed species distribution models for the ten remaining species in the genus Achatinella under present and future climate scenarios, within the historical range on O‘ahu, as well as areas outside the historical range across the Hawaiian Islands. I found that ~98% of suitable area across the Hawaiian Islands is outside of the historical range. Additionally, most of the climate-suitable habitat under future conditions on O‘ahu do not overlap with areas where populations are currently persisting, suggesting that without translocation, these species may become extinct sometime before the end of the century. Our results raise alarms regarding the likely impacts of climate change on wildlife long before the end of the century and highlight the importance of translocations outside the historical range for the persistence of climate-sensitive species.