Mon, Aug 15, 2022: 2:15 PM-2:30 PM
513E
Background/Question/MethodsClimate change poses an existential threat to biodiversity, given our understanding of the importance of climate in shaping species’ geographic distributions. Climate envelope or species distribution models are commonly used to predict how species will respond to climate change. In doing so, it is assumed that individual- and population-level climatic tolerances match species-level climatic tolerances. This gives rise to the leading edge-trailing edge paradigm for range change: populations at the cool edge of a species’ distribution are expected to benefit from warming, whereas populations at the warm edge are expected to decline. We challenged this paradigm with a spatial network of 1,633 growth-ring time series sampled from an aridland pine (Pinus edulis, common or two-needle pinon), collected in 937 forest inventory plots encompassing this species’ entire geographic distribution.
Results/ConclusionsA Bayesian multiple regression analysis of ring widths showed that growth of P. edulis increases with temperature variation across space (warmer sites have higher growth rates, especially at relatively wet, warm sites) but that trees everywhere grow less in warmer-than-average years. This ubiquitous negative response to interannual temperature variability implies that instead of expecting leading edge populations to benefit from warming, we should expect all populations to experience decreased performance (and fitness). Thus we question the assumption underlying the use of climate envelope models that global (species-wide) climatic tolerances can be translated directly into projections of range change, ignoring individual-level plasticity and local adaptation. Our results imply that climate envelope (species distribution) models underestimate the risk of extinction posed by climate change. We conclude that range projections should be informed with a combination of longitudinal (time series) and spatial data.
Results/ConclusionsA Bayesian multiple regression analysis of ring widths showed that growth of P. edulis increases with temperature variation across space (warmer sites have higher growth rates, especially at relatively wet, warm sites) but that trees everywhere grow less in warmer-than-average years. This ubiquitous negative response to interannual temperature variability implies that instead of expecting leading edge populations to benefit from warming, we should expect all populations to experience decreased performance (and fitness). Thus we question the assumption underlying the use of climate envelope models that global (species-wide) climatic tolerances can be translated directly into projections of range change, ignoring individual-level plasticity and local adaptation. Our results imply that climate envelope (species distribution) models underestimate the risk of extinction posed by climate change. We conclude that range projections should be informed with a combination of longitudinal (time series) and spatial data.