Disentangling the Effects of Climate and Landscape Change on Bird Population Trends in the Western U.S. and Canada Completed

Climate change has been implicated in the range shifts and population declines of many species, but the confounding of climate change with other variables, particularly landscape change, hampers inference about causation. Climate envelope models have been used to predict population trends and future distributions, but the reliability of such predictions remains relatively unknown; without tests of model accuracy, policy development will be based on highly uncertain ground. Our team assembled recent developments in change detection mapping and species modeling. Specifically, our objectives were to: (1) use 32-year data on bird distributions to test the reliability of climate envelope models, (2) test whether changes in climate are linked to bird population declines over the past 32 years and, (3) assess the relative importance of climate versus landscape change in explaining changes in species distributions.