Biological invasions and climate change amplify each other’s effects on dryland degradation

作者：Sujith Ravi, Darin J. Law, Joshua S. Caplan, Greg A. Barron‐Gafford, Katerina Dontsova, Javier F. Espeleta, Juan Camilo Villegas, Gregory S. Okin, David D. Breshears, Travis E. Huxman · 发表于：Global Change Biology · 年份：2021 · DOI：10.1111/gcb.15919 · 被引用次数：60 · 研究领域：Rangeland and Wildlife Management、Ecology and Vegetation Dynamics Studies、Plant Water Relations and Carbon Dynamics

Climate models predict that, in the coming decades, many arid regions will experience increasingly hot conditions and will be affected more frequently by drought. These regions are also experiencing rapid vegetation change, notably invasion by exotic grasses. Invasive grasses spread rapidly into native desert ecosystems due, in particular, to interannual variability in precipitation and periodic fires. The resultant destruction of non-fire-adapted native shrub and grass communities and of the inherent soil resource heterogeneity can yield invader-dominated grasslands. Moreover, recurrent droughts are expected to cause widespread physiological stress and mortality of both invasive and native plants, as well as the loss of soil resources. However, the magnitude of these effects may differ between invasive and native grasses, especially under warmer conditions, rendering the trajectory of vegetated communities uncertain. Using the Biosphere 2 facility in the Sonoran Desert, we evaluated the viability of these hypothesized relationships by simulating combinations of drought and elevated temperature (+5°C) and assessing the ecophysiological and mortality responses of both a dominant invasive grass (Pennisetum ciliare or buffelgrass) and a dominant native grass (Heteropogan contortus or tanglehead). While both grasses survived protracted drought at ambient temperatures by inducing dormancy, drought under warmed conditions exceeded the tolerance limits of the native species, resulti...