Field surveys for vanishing species: Closing data gaps to understand climate change impacts on Hawaiian land snails and preserve biodiversity

Foreground of large colorful snail on a broad leaf, against blurred background of eroded hills and out to the sea.
Over 750 species of terrestrial snails used to live in the Hawaiian Islands, but many have been lost in the past century. This Oʻahu tree snail (Achatinella sowerbyana) is endemic, living only in the highest native forests of the Koʻolau and Waiʻanae mountain ranges. (Photo: David Sischo, USFWS)

The Hawaiian Islands have an extremely diverse number of plants and animals found nowhere else on Earth. Changes brought about by the arrival of humans and the introduction of non-native predators, weeds, and diseases has led to the extinction of hundreds of Hawaiian species – far more than any other U.S. state. To help Hawaiʻi prevent additional species from becoming extinct and to restore at-risk species to secure population sizes, the state, along with federal, private, and scientific partners, is currently developing and implementing a comprehensive conservation plan to protect and manage over 300 declining and endangered native plants and animals on the islands of Maui, Molokaʻi, and Lānaʻi.

This effort by the state will map the current distribution of each species, estimate their future distributions in a changing climate, identify the minimum habitat needed to conserve each species, plan for responses to a changing climate, and use optimization methods to select a suite of management areas that both minimizes management costs and effectively restores all species. Knowledge of where plants and birds occur on these islands is well established. However, a group of biologically and culturally important Hawaiian animals, the land and tree snails, is very poorly known. Decision makers lack the information on these species needed to develop and prioritize conservation actions or to plan for a changing climate.

This project will fill major gaps in our knowledge for over 50 at-risk Hawaiian tree snails. Two field biologists will be hired to survey for the most critically imperiled snails. Survey results and the modeled distribution maps for these species will be incorporated into the three island landscape-scale Conservation Plan to ensure that habitat for these species is protected and that cost-effective conservation actions are identified and implemented. The inclusion of critically threatened land snails along with birds, plants, and insects into this planning effort will result in a spatially-explicit conservation plan that is innovative, addresses multiple taxonomic groups, and unlike any other effort to date in Hawaiʻi.





Jonathan Price
Professor of Geography, UH Hilo


Scott Fretz
Hawaiʻi Division of Forestry & Wildlife