Using the Forest Service Climate Change Tree Atlas and National Land Cover Data to predict changes in forest composition in Northeastern National Parks

Background/Question/Methods

Forests are a critical resource in northeastern National Parks, and their long-term health is of great concern to park managers and the public. Prioritizing management efforts in the age of climate change is a huge challenge facing park managers. Knowing how forest composition is expected to change in parks is essential for making informed decisions. This includes predicting winners and losers among current forest species and new species that may be better suited to the expected future conditions. Predicting the capacity for new species to naturally migrate into parks is also important for long-term planning.

For 10 northeastern parks in the Northeast Temperate Network (NETN), we used the US Forest Service's Climate Change Tree Atlas predictions of suitable habitat for 2100 to determine which of the current species may persist under the high emissions scenario. We then determined which new species were predicted to have suitable habitat in park forests by 2100. We simulated random dispersal from the northern distribution of the new species range using the species' current modeled importance values and known dispersal rates. We incorporated the 2011 National Land Cover Data (NLCD) in the migration simulations to determine the potential success or failure of random dispersal events.

Results/Conclusions

Based on the GCM3_HI scenario of the Climate Change Tree Atlas, terrestrial habitats in NETN parks will be more suitable for oak and hickory species at the turn of the century than the northern hardwood and boreal species that currently dominate. The landscape surrounding NETN parks, particularly in the southern part of NETN (New Jersey, Connecticut, and southern New York), is highly fragmented with considerable non-forest and developed habitat. Given typical dispersal rates and age to maturity for the oak and hickory species that are predicted to gain suitable habitat in NETN, preliminary results suggest that habitat fragmentation and human development will be a major impediment to natural migration of tree species. Therefore, tree species that are predicted to gain suitable habitat in NETN parks may require some level of assisted migration into the region. The Climate Change Tree Atlas predictions and the simulations in our study will help determine which species may be most appropriate for assisted migration in different parks. We will then apply the migration simulations assuming assisted migration to determine the potential for parks to serve as source populations of newly established species in the surrounding landscape.