Spatial heterogeneity in climate change effects decouples the long‐term dynamics of wild reindeer populations in the high Arctic

作者：Brage Bremset Hansen, Åshild Ønvik Pedersen, Bart Peeters, Mathilde Le Moullec, S. D. Albon, Ivar Herfindal, Bernt‐Erik Sæther, Vidar Grøtan, Ronny Aanes · 发表于：Global Change Biology · 年份：2019 · DOI：10.1111/gcb.14761 · 被引用次数：79 · 研究领域：Indigenous Studies and Ecology、Wildlife Ecology and Conservation、Ecology and biodiversity studies

The 'Moran effect' predicts that dynamics of populations of a species are synchronized over similar distances as their environmental drivers. Strong population synchrony reduces species viability, but spatial heterogeneity in density dependence, the environment, or its ecological responses may decouple dynamics in space, preventing extinctions. How such heterogeneity buffers impacts of global change on large-scale population dynamics is not well studied. Here, we show that spatially autocorrelated fluctuations in annual winter weather synchronize wild reindeer dynamics across high-Arctic Svalbard, while, paradoxically, spatial variation in winter climate trends contribute to diverging local population trajectories. Warmer summers have improved the carrying capacity and apparently led to increased total reindeer abundance. However, fluctuations in population size seem mainly driven by negative effects of stochastic winter rain-on-snow (ROS) events causing icing, with strongest effects at high densities. Count data for 10 reindeer populations 8-324 km apart suggested that density-dependent ROS effects contributed to synchrony in population dynamics, mainly through spatially autocorrelated mortality. By comparing one coastal and one 'continental' reindeer population over four decades, we show that locally contrasting abundance trends can arise from spatial differences in climate change and responses to weather. The coastal population experienced a larger increase in ROS, and a s...