How extreme is extreme? Demographic approaches inform the occurrence and ecological relevance of extreme events

Projected increases in the variability of both temperature and precipitation will result in the greater likelihood and magnitude of extreme weather (e.g., cold snaps, droughts, heat waves) with potential implications for animal populations. Despite the ecological consequences of extreme weather, there are several challenges in identifying extreme events and measuring their influence on key demographic processes in free-living animals. First, there is often a mismatch between the spatial and/or temporal resolution of biological and climate data, masking the ability to draw inferences about how species and populations respond to extreme events. Second, there are multiple approaches for identifying an extreme event ranging from statistical definitions (e.g., standardized deviates) to species-specific biological thresholds. Lastly, the impacts of extreme weather on species can vary as a function of differences in exposure and intrinsic sensitivity to climate variability. In the Northern Hem...