Erosion-vegetation interactions The impact of vegetation on erosion rates is hard to gauge. Although vegetation can hold soils in place mechanically, root systems can also loosen soils or even help to fracture rock. These processes can increase erosion, especially because areas of heavy vegetation tend to be in areas with high precipitation rates. Starke et al. tackled this issue using a large set of observations that span 3500 km of the Andes mountain range. They found a complex set of interactions where increasing vegetation decreases erosion in more arid regions but can accelerate erosion in vegetation dense regions. Science, this issue p. 1358 Observations from the Andes help outline the contribution of vegetation to erosion rates. Vegetation influences erosion by stabilizing hillslopes and accelerating weathering, thereby providing a link between the biosphere and Earth’s surface. Previous studies investigating vegetation effects on erosion have proved challenging owing to poorly understood interactions between vegetation and other factors, such as precipitation and surface processes. We address these complexities along 3500 kilometers of the extreme climate and vegetation gradient of the Andean Western Cordillera (6°S to 36°S latitude) using 86 cosmogenic radionuclide–derived, millennial time scale erosion rates and multivariate statistics. We identify a bidirectional response to vegetation’s influence on erosion whereby correlations between vegetation cover and erosion range from negative (dry, sparsely vegetated settings) to positive (wetter, more vegetated settings). These observations result from competing interactions between precipitation and vegetation on erosion in each setting.

中文翻译：

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植被对南美洲西部侵蚀率的纬度影响

侵蚀-植被相互作用 植被对侵蚀率的影响很难衡量。虽然植被可以机械地固定土壤，但根系也可以松动土壤，甚至有助于破碎岩石。这些过程会增加侵蚀，特别是因为植被茂盛的地区往往位于降水率高的地区。斯塔克等人。使用跨越 3500 公里安第斯山脉的大量观测来解决这个问题。他们发现了一组复杂的相互作用，其中增加植被会减少干旱地区的侵蚀，但可以加速植被密集地区的侵蚀。科学，这个问题 p。1358 安第斯山脉的观测有助于概述植被对侵蚀率的贡献。植被通过稳定山坡和加速风化来影响侵蚀，从而提供生物圈和地球表面之间的联系。由于对植被与其他因素（例如降水和地表过程）之间的相互作用知之甚少，先前调查植被对侵蚀的影响的研究已证明具有挑战性。我们使用 86 种宇宙放射性核素衍生的千年时间尺度侵蚀率和多变量统计数据来解决安第斯西部山脉（纬度 6°S 至 36°S）3500 公里极端气候和植被梯度的这些复杂问题。我们确定了植被对侵蚀影响的双向响应，其中植被覆盖度和侵蚀之间的相关性从负面（干燥、植被稀疏的环境）到正面（更潮湿、植被较多的环境）不等。