Weather extremes are among the most impactful aspects of climate change and are projected to increase in frequency in many regions of the world. Birds are widely recognized as indicators of climate change and their interactions with weather extremes have been well documented across broad spatial and temporal scales. However, studies of the short-term effects of weather extremes have been largely limited to opportunistic, localized case studies, making comparisons across broader landscapes difficult. We used historical climate records and long-term bird survey data to analyze the impacts of short-term temperature extremes on bird abundance across the central U.S. prairies. Through climatologically aided mapping, we derived temperature maximum and minimum extreme indices across multiple short-term temporal scales, and fit them to 20 years of bird count data (1997-2016). Using generalized linear mixed models and an information theoretical approach, we evaluated how the inclusion of temperature extremes indices affects model performance, comparing across species, functional groups, and regions.
Results/Conclusions
Species level analysis of 31 common birds saw improvement in model performance for nearly two thirds (20) of all species when temperature extremes were included. Of these, 15 saw improvement across nearly all time scales examined. A minority (3) had no discernable pattern, with the remainder not showing any improvement in model performance. For most species, the top performing model was consistent across all time scales, suggesting the species may be responding to a specific type of temperature extreme, rather than a combination of many or general volatility. Preliminary analysis of foraging functional groups indicates that four out five guilds saw improved model performance with the inclusion of temperature extremes. Insectivorous air salliers responded negatively to cold daytime extremes, whilst ground and lower canopy omnivores responded negatively to warm nighttime temperatures. Warm daytime extremes positively affected ground insectivore abundance and negative affected ground omnivore abundance, with cold nighttime temperatures exhibiting the opposite effect. Overall this indicates that short-term temperature extremes should be considered in addition to baseline weather parameters when examining bird abundance.