Identifying resilient restoration targets: range-wide habitat analysis and climate-change outcomes for American chestnut (Castanea dentata) in Eastern US

Abstract

In spite of the near-eradication of the American chestnut (Castanea dentata) over the last century by an invasive fungal pathogen, meaningful progress has been made in recent decades towards generating blight-resistant varieties for eventual restoration in its former native range in the Eastern US. Using known surviving specimen locations and environmental data, Maximum Entropy species distribution modeling software was used to determine optimal present-day habitat characteristics. Model projection was used to estimate shifts in ideal habitat under moderate and extreme carbon-emission climate scenarios over several time horizons ranging between present day and 2100. Sites with suitable habitat across all scenarios were identified and recommended as restoration targets, most notably lowland New England and high-elevation Southern and Mid-Atlantic Appalachian regions. The current study builds upon previous work by combining fine-resolution data, regional-scale breadth, future climate models, and a different source of chestnut location data to produce a species distribution model that is concurrently useful to local sample collectors, state-level planners and long-term restoration managers.