The Grassland-Shrubland Regime Shift in the Southwestern United States: Misconceptions and Their Implications for Management
The Grassland-Shrubland Regime Shift in the Southwestern United States: Misconceptions and Their Implications for Management
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DOI：
10.1093/biosci/biy065
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发表时间：
2018-09-01
期刊：
影响因子：
10.1
通讯作者：
Webb, Nicholas P.
中科院分区：
文献类型：
--
作者：
Bestelmeyer, Brandon T.;Peters, Debra P. C.;Webb, Nicholas P.
半干旱草原向灌木丛状态的转变是陆地生态系统政权转变最广泛认可的例子之一。尽管如此，引起草地-灌木丛转变的过程及其后果尚不完全清楚。我们对关于沙漠草原这些转变的一些误解提出了质疑，包括（a）它们目前受到当地牲畜放牧和干旱事件的控制，（b）它们代表着严重的土地退化，以及（c）草原状态的恢复是不可能的。草地-灌木丛转变是生态和社会多种驱动因素和反馈系统在多个空间和时间尺度上相互作用的产物。无论是否清除灌木，灌木丛州内的草恢复都会产生新的生态系统，这些生态系统与历史草原不同，但提供重要的生态系统服务。预计气候变化的增加可能会进一步促进多年生草本植物被旱生灌木取代。本文提供了面对不断变化的生物物理和社会经济环境时管理草地-灌木丛转变的指南。
Transitions front semiarid grassland to shrubland states are among the most widely recognized examples of regime shifts in terrestrial ecosystems. Nonetheless, the processes causing grassland-shrubland transitions and their consequences are incompletely understood. We challenge several misconceptions about these transitions in desert grasslands, including that (a) they are currently controlled by local livestock grazing and drought events, (b) they represent severe land degradation, and (c) restoration of grassland states is impossible. Grassland-shrubland transitions are the products of multiple drivers and feedback systems, both ecological and social, interacting at multiple scales of space and time. Grass recovery within shrubland states with and without shrub removal-produces novel ecosystems that are dissimilar from historical grasslands but that provide important ecosystem services. Projected increases in climate variability are likely to promote the further displacement of perennial grasses by xerophytic shrubs. This article offers guidelines for managing grassland-shrubland transitions in the face of changing biophysical and socioeconomic circumstances.