Department of Biology, University of Ottawa Ottawa, Ontario, Canada
Background/Question/Methods
The world is currently facing a biodiversity crisis with many species undergoing severe population declines, with climate change acting as a driver of species declines by pushing species past their thermal tolerance limits. As a result, many species have started shifting their ranges towards the poles and higher altitudes to avoid these increasing temperatures. However, in addition to average warming species are experiencing increased extreme weather events. El Nino Southern Oscillations (ENSO) are one such extreme weather event that is predicted to increase in severity due to climate change. ENSO and climate change both have spatially heterogenous effects on weather patterns across the globe, however it is currently unknown how these phenomena combine to impact species thermal niche position. Here we calculate the thermal niche position using the Thermal Position Index (TPI), which determines how close species are to their thermal tolerance maximum. Utilizing historical WorldClim data we determine the baseline thermal niche position for terrestrial mammals across the globe, corresponding to the years 1961-1975. Following the baseline calculation each species’ thermal position is determined across their range for both ENSO years and non-ENSO years during the current period (2000-2018).
Results/Conclusions
Both ENSO and non-ENSO models are then compared to determine how climate change and ENSO events combine to affect the thermal position of terrestrial mammals. With many species in the tropical regions of the planet already approaching their thermal tolerance limits the results of this analysis reveal how climate change in combination with extreme weather events is driving changes of thermal position for species within global biodiversity hotspots. These models reveal important details regarding regions that are experiencing increases in temperature due to climate change, ENSO events, and a combination of the two phenomena. Importantly, the models also reveal areas that are likely to experience higher rates of local species extinctions due to climate change and extreme weather events. Utilizing the results provided by the TPI models conservation initiatives can be better targeted towards areas that are most at risk and account for species range shifts as a result of climate change and extreme weather events.
