Spatio-Temporal Statistical Models for Forecasting Climate Change Effects on Bird Distribution

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Ecological indicators of climate change are needed to measure concurrent changes in ecological systems, inform management decisions, and forecast the consequences of climate change. We seek to develop robust bird-based, climate-change indicators using North American Breeding Bird Survey data.

The Challenge: Ecological indicators of climate change are needed to measure concurrent changes in ecological systems, inform management decisions, and forecast the consequences of climate change. Breeding bird distributions are predicted to be sensitive to changes in climate, and could be useful climate-change indicators. We seek to develop robust bird-based, climate-change indicators using data from the North American Breeding Bird Survey (BBS), a geographically and temporally (1966 – present) extensive data set on breeding bird distributions in North America.

The Science: Imperfect detection and complex space-time dynamics of species distributions challenge the development of reliable indicators from BBS data. Imperfect detection may obscure biological processes behind observation error, while the spatial and temporal dynamics of species distribution require flexible and sometimes highly parameterized statistical models to accurately describe relationships between climate and species distributions. Using space-time dynamic occupancy models, we developed predictive models of species occurrence, and summaries of species range shifts in response to climate conditions.   Furthermore, these dynamic models estimate transition probabilities, which allow forecasts of species distribution for species that are not in equilibrium (Figs. 2 & 3).

The Future: Building on the work of Clement and others (2016; Global Change Biology 22:3273-3285), we developed a space-time dynamic occupancy model to characterize the spatial and temporal dynamics of bird distribution and develop an index to use as an indicator of climate change response; a composite (multi-species) index is currently under development. Such indicators can be used to track changes in species distributions and to test hypotheses about the effects of climate change. For example, changes in range size or boundaries in successive years can provide a metric reflecting expansions or contractions in range size over time in response to climate change. Other ecological hypotheses predict increases in rates of local colonization at northern edges of species ranges and increased local extinction at the southern edges of species ranges. The current work can also be used to test additional hypotheses that predict that the effect of climate change on the size, location, and dynamics of ranges will depend on the ecological niches of different species.