2020 ESA Annual Meeting (August 3 - 6)

COS 48 Abstract - Range-wide evaluation of 25 tree species under climate change by combining USA's and Canada's forest inventories

Anantha Prasad1, John Pedlar2, Matt Peters1, Daniel McKenney3, Louis Iverson1, Stephen N. Matthews4 and Bryce T. Adams4, (1)Northern Institute of Applied Climate Science, Northern Research Station, USDA Forest Service, Delaware, OH, (2)Canadian Forest Service, ON, Canada, (3)Great Lakes Forestry Centre, Canadian Forest Service, Sault Ste.Marie, ON, Canada, (4)School of Environment and Natural Resources, The Ohio State University, Columbus, OH
Background/Question/Methods

Range-wide analysis of tree species habitats and colonization potential under climate change is a challenge since inventory data typically span only national boundaries and methods employed are often incompatible across countries. Here we combine, for the first time, the relative abundance derived from USA's Forest Inventory Analysis with gridded estimates of species composition from Canada's National Forest Inventory, based on photo plot data. We model future climatic habitats and colonization potentials for 25 tree species using 21 climate variables under RCP 4.5 and RCP 8.5 climate scenarios. We use consensus predictions based on a multi-model regression ensemble to map suitable habitats (HQ) as low, medium and high quality classes. A long-distance migration model based on current distribution and historical migration rates is used to assess colonization likelihoods (CL) for ~ 100 years, as absent, low, medium and high likelihood classes. The HQ classes are combined with CL to map and evaluate various combinations of HQ+CL outcomes. We minimize model confoundment and bias by first modelling climate response and then employ post-model filters to address additional constraints such as land-use and land-cover.

Results/Conclusions

For the species examined here, habitat losses were primarily experienced along southern range limits, while habitat gains were associated with northern range limits (especially under RCP 8.5). However, for many species, southern range limits are projected to remain relatively intact, albeit with reduced habitat quality. Thus, while leading edge habitats are projected to expand rapidly due to greater warming at these latitudes, trailing edge populations may remain viable, but subject to greater climatic stress. Even though large parts of Canada and USA's Alaska are poised to gain climatically suitable habitat for many tree species, our models predict that only a small portion of the climatic habitat generated by climate change will be colonized naturally by the end of the current century - even with optimistic tree migration rates. However, considerable variation in the extent to which species were projected to colonize newly gained habitats points to the need for significant management efforts, including assisted migration of populations and species in order to conserve and promote tree species that are deemed important for economic or ecological reasons. Our work highlights the need for employing range-wide data, evaluating colonization potentials, and increased cross-border cooperation.