Abstract

Climate change is affecting species and resources across National Parks. Novel climatic conditions are likely to result in novel species assemblages; this means that the species currently present within parks may decline or disappear while more southerly or warm-adapted species may gain substantial habitat. Stewarding forests for continuous change is a challenge for park managers; however, understanding projected rates and directions of forest change should facilitate monitoring and management efforts on park lands. To support such efforts for Acadia National Park, we analyzed projected changes in tree habitat suitability for 83 trees species for three future periods (2040, 2070, and 2100). We present model output from two scenarios, the ‘least change’ and ‘most change’ scenarios that represent the rough bounds of plausible future conditions. General trends in the data indicate strongly decreasing habitat suitability for 13 species (16% of species), minor change for 18 species (22% of species), and large increases or new habitat for 52 species (62% of species). Boreal tree species, including fir, spruce, aspen, and paper birch, have strong decreases in suitable habitat under both future scenarios whereas most temperate species currently present retain suitable habitat. Under the warmest scenario, several oak, hickory, and pine species common in the southeast and south central U.S. are likely to have suitable habitat in the Acadia region by the end of the 21st century. As climate change continues and forest responses accelerate, management will need to shift from actions that are no longer effective to new strategies that achieve desired conditions in a continuously changing world.