Demographic range models

Predicting the future distributions of species under climate change requires an understanding of the factors that determine the dimensions of the species’ ecological niche. From a demographic perspective, the ecological niche is the set of conditions under which a species has a positive population growth rate. Most models of species distributions assume climate is the primary determinant of the ecological niche and therefore range limits, but biotic factors, such as competition, can also be important determinants of range limits. We use Forest Inventory and Analysis data (FIA) to test for the effects of both climate and competition on the vital rates of Pinus edulis (common pinyon pine). We then use integral projection models to estimate population growth rates and build demographic range models to project the distribution of Pinus edulis. Because the FIA data are not well suited to fit regeneration models and to estimate the response to disturbances of Pinus edulis (fires were largely surpressed), we explore inverse calibration approaches as a potential solution for addressing mismatches between model predictions and observed distributions.