Understanding spatiotemporal variation in environmental conditions is important in order to determine how climate change will impact ecological communities. Theory predicts that a reddening of environmental noise (an increase in its temporal autocorrelation) is likely to promote local extinction risk by increasing the duration and magnitude of unfavorable conditions (i.e., eliminating temporal refugia). Similarly, increased spatial autocorrelation is expected to promote both local and regional extinction risk by decoupling source and sink populations (i.e., eliminating spatial refugia). Increased spatial and temporal autocorrelation of environmental factors like temperature may thus interact synergistically to destabilize ecological communities across scales by disrupting both temporal and spatial rescue effects. Although increases in spatial and temporal autocorrelation of temperature are documented in historical data, little is known about how climate change will impact these values. We examined air temperature data from 21 General Circulation Models under the business-as-usual carbon emission scenario (RCP8.5) to quantify patterns of spatial and temporal autocorrelation between 1871 and 2099.
Results/Conclusions
Spatial and temporal autocorrelation increased over time globally and in both temperate and tropical regions. Temporal trends in autocorrelation were statistically significant across time windows ranging in length from five to ten years. Piecewise regression analysis showed consistent breakpoints around 2030 globally, and spatial trends in autocorrelation were statistically significant after the breakpoint across time windows. Additionally, the consistent breakpoint in the linear regressions relating spatial and temporal autocorrelation to time globally around 2030 indicated an unexpected threshold response in the autocorrelation of temperature. Under anthropogenic climate change, spatial and temporal homogeneity of temperature is expected to increase, which may negatively impact connectivity between source and sink populations and thus reduce the persistence of ecological communities. Overall, our results suggest that extinction risk in ecological communities may increase under climate change because increased spatial and temporal autocorrelation of temperature is expected to erode both spatial and temporal refugia.