Oney, B; Reineking, B; O'Neill, GA; Kreyling, J: Intraspecic variation buffers projected climate change impacts on Pinus contorta, Ecology and Evolution, doi: 10.1002/ece3.426 (2013) | |
Abstract: Species distribution modeling (SDM) is an important tool to assess the impact of global environmental change. Many species exhibit ecologically relevant intraspecic variation, and few studies have analyzed its relevance for SDM. Here, we compared three SDM techniques for the highly variable species Pinus contorta. First, applying a conventional SDM approach, we used MaxEnt to model the subject as a single species (species model), based on presence absence observations. Second, we used MaxEnt to model each of the three most prevalent subspecies independently and combined their projected distributions (subspecies model). Finally, we used a universal growth transfer function (UTF), an approach to incorporate intraspecic variation utilizing provenance trial tree growth data. Dierent model approaches performed similarly when predicting current distributions. MaxEnt model discrimination was greater (AUC { species model: 0.94, subspecies model: 0.95, UTF: 0.89), but the UTF was better calibrated (slope and bias { species model: 1.31 and -0.58, subspecies model: 1.44 and -0.43, UTF: 1.01 and 0.04, respectively). Contrastingly, for future climatic conditions, projections of lodgepole pine habitat suitability diverged. In particular, when the species' intraspecic variability was acknowledged, the species was projected to better tolerate climatic change as related to suitable habitat without migration (subspecies model: 26% habitat loss or UTF: 24% habitat loss vs. species model: 60% habitat loss), and given unlimited migration may increase amount of suitable habitat (subspecies model: 8% habitat gain or UTF: 12% habitat gain vs. species model: 51% habitat loss) in the climatic period 2070{2100 (SRES A2 scenario, HADCM3). We conclude that models derived from within-species data produce dierent and better projections, and coincide with ecological theory. Furthermore, we conclude that intraspecic variation may buer against adverse eects of climate change. A key future research challenge lies in assessing the extent to which species can utilize intraspecic variation under rapid environmental change. |