Experiment, monitoring, and gradient methods used to infer climate change effects on plant communities yield consistent patterns

作者：Sarah C. Elmendorf, Gregory H. R. Henry, Robert D. Hollister, Anna Maria Fosaa, William A. Gould, Luise Hermanutz, Annika Hofgaard, Ingibjörg S. Jónsdóttir, Janet C. Jorgenson, Esther Lévesque, Borgþór Magnússon, Ulf Molau, Isla H. Myers‐Smith, Steven F. Oberbauer, Christian Rixen, C. E. Tweedie, Marilyn D. Walker · 发表于：Proceedings of the National Academy of Sciences · 年份：2014 · DOI：10.1073/pnas.1410088112 · 被引用次数：264 · 研究领域：Climate change and permafrost、Geology and Paleoclimatology Research、Cryospheric studies and observations

Inference about future climate change impacts typically relies on one of three approaches: manipulative experiments, historical comparisons (broadly defined to include monitoring the response to ambient climate fluctuations using repeat sampling of plots, dendroecology, and paleoecology techniques), and space-for-time substitutions derived from sampling along environmental gradients. Potential limitations of all three approaches are recognized. Here we address the congruence among these three main approaches by comparing the degree to which tundra plant community composition changes (i) in response to in situ experimental warming, (ii) with interannual variability in summer temperature within sites, and (iii) over spatial gradients in summer temperature. We analyzed changes in plant community composition from repeat sampling (85 plant communities in 28 regions) and experimental warming studies (28 experiments in 14 regions) throughout arctic and alpine North America and Europe. Increases in the relative abundance of species with a warmer thermal niche were observed in response to warmer summer temperatures using all three methods; however, effect sizes were greater over broad-scale spatial gradients relative to either temporal variability in summer temperature within a site or summer temperature increases induced by experimental warming. The effect sizes for change over time within a site and with experimental warming were nearly identical. These results support the view that...