Plants as river system engineers
Plants as river system engineers
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DOI：
10.1002/esp.3397
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发表时间：
2014-01-01
影响因子：
3.3
通讯作者：
Gurnell, Angela
中科院分区：
文献类型：
--
作者：
Gurnell, Angela
生长在河流廊道内的植物既影响河流的演变过程，也对河流演变过程作出反应。其地上生物量改变流场并保留沉积物，而其地下生物量影响基质的水力和机械特性，从而影响陆地表面的水分状况和侵蚀敏感性。本文回顾了20世纪50年代以来对河流系统内植被地貌影响的研究。在世纪后期，这项研究主要是通过实地观察进行的，但在21世纪世纪的早期，补充领域，水槽和理论/建模调查作出了贡献的重大进展，了解植物对河流系统的影响。水槽实验已经证明了植被在确定河流平面形态，特别是从多线程形式到单线形式的过渡中的基本作用，并提供了对水流-植被-沉积物反馈和地貌形成的见解，包括诸如通道阻塞和撕脱等过程。与此同时，建模人员将依赖水分的植物生长、树冠和根系结构及其对水流阻力和沉积物/堤岸加固的影响等因素纳入形态动力学模型。与此同时，实地调查表明，植被对河流系统的影响比以前认识到的更为重要和复杂。现在很明显，从单个植物到整个森林河流走廊，植物对河流系统的影响在空间尺度上都很重要。小植物尺度的现象结构斑块尺度的地貌形式和过程，斑块之间的相互作用几乎肯定是至关重要的大规模和长期的地貌现象。植物的影响也随着时间的推移不断变化，因为地上和地下生物量在年度生长周期内、在较长期的生长轨迹上以及在气候、水文和河流波动和极端情况等外部变化驱动因素的作用下发生变化。版权所有（c）2013约翰威利父子有限公司
Plants growing within river corridors both affect and respond to fluvial processes. Their above-ground biomass modifies the flow field and retains sediment, whereas their below-ground biomass affects the hydraulic and mechanical properties of the substrate and consequently the moisture regime and erosion susceptibility of the land surface. This paper reviews research that dates back to the 1950s on the geomorphological influence of vegetation within fluvial systems. During the late twentieth century this research was largely pursued through field observations, but during the early years of the twenty-first century, complementary field, flume and theoretical/modelling investigations have contributed to major advances in understanding the influence of plants on fluvial systems. Flume experiments have demonstrated the fundamental role of vegetation in determining river planform, particularly transitions from multi- to single-thread forms, and have provided insights into flow-vegetation-sediment feedbacks and landform building, including processes such as channel blockage and avulsion. At the same time, modellers have incorporated factors such as moisture-dependent plant growth, canopy and root architecture and their influence on flow resistance and sediment/bank reinforcement into morphodynamic models. Meanwhile, field investigations have revealed that vegetation has a far more important and complex influence on fluvial systems than previously realized. It is now apparent that the influence of plants on river systems is significant across space scales from individual plants to entire forested river corridors. Small plant-scale phenomena structure patch-scale geomorphological forms and processes, and interactions between patches are almost certainly crucial to larger-scale and longer-term geomorphological phenomena. The influence of plants also varies continuously through time as above- and below-ground biomass change within the annual growth cycle, over longer-term growth trajectories, and in response to external drivers of change such as climatic, hydrological and fluvial fluctuations and extremes. Copyright (c) 2013 John Wiley & Sons, Ltd.