Modeling the functional influence of vegetation type on streambank cohesion
Modeling the functional influence of vegetation type on streambank cohesion
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DOI：
10.1002/esp.3577
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发表时间：
2014-07
影响因子：
3.3
通讯作者：
L. Polvi;E. Wohl;D. Merritt
中科院分区：
文献类型：
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作者：
L. Polvi;E. Wohl;D. Merritt
植被在增加粘性和稳定河岸方面的重要作用已在河流地貌的几个方面得到广泛认可，包括河流恢复和长期河道变化的研究。在平面形态之间的变化编织，曲流，和anbranching形式已被归因于植被的水力粗糙度和银行的稳定性的影响。然而，这些研究集中在水槽研究中使用模拟植被，或案例研究具有一个物种，这是常见的入侵。我们目前的功能差异银行稳定的根特性和增加的凝聚力，与植被分类为木本和非木本和树木，灌木，禾本科植物和杂类草的植被组。我们分析了落基山脉南部河岸地区常见的14个物种的根系形态和抗拉强度，这些物种位于科罗拉多前岭山地和亚高山地区的山地和亚高山地带的沿着河岸野外。使用基于物理的河岸稳定性模型（BSTEM）的植被根分量（RipRoot），我们估计了添加14种中的每一种的各种沉积物质地的附加内聚力。木本和非木本植被之间以及四种植被类型之间的根系抗张强度曲线系数、侧根长度和最大根径存在显著差异。木本植被（树木和灌木）的所有三个参数的值都高于非木本物种。树根比杂树根能显著增加河岸的凝聚力。此外，根茎可能在确定根系对河岸稳定的河段尺度效应方面发挥重要作用。植被类别之间根系特征的差异和增加的凝聚力有几个重要的影响，包括确定地貌变化的可能性，制定使用河岸稳定植被的指导方针，以及将植被的影响与有利于生态系统功能的地貌结构联系起来。版权所有© 2014约翰威利父子有限公司.
The important role of vegetation in adding cohesion and stabilizing streambanks has been widely recognized in several aspects of fluvial geomorphology, including stream restoration and studies of long‐term channel change. Changes in planform between braided, meandering, and anabranching forms have been attributed to the impacts of vegetation on hydraulic roughness and bank stability. However, these studies focus either on flume studies where analog vegetation is used, or case studies featuring one species, which is commonly invasive. We present functional differences of bank‐stabilizing root characteristics and added cohesion, with vegetation categorized as woody and non‐woody and by the vegetation groups of trees, shrubs, graminoids, and forbs. We analyzed root morphology and tensile strength of 14 species common to riparian areas in the southern Rocky Mountains, in field sites along streambanks in the montane and subalpine zones of the Colorado Front Range. Using the vegetation root component (RipRoot) of a physically‐based bank stability model (BSTEM), we estimated the added cohesion for various sediment textures with the addition of each of the 14 species. Significant differences exist between woody and non‐woody vegetation and between the four vegetation categories with respect to the coefficient of the root tensile strength curve, lateral root extent, and maximum root diameter. Woody vegetation (trees and shrubs) have higher values of all three parameters than non‐woody species. Tree roots add significantly more cohesion to streambanks than forb roots. Additionally, rhizomes may play an important role in determining the reach‐scale effects of roots on bank stabilization. Differences in root characteristics and added cohesion among vegetation categories have several important implications, including determining the likelihood of planform change, developing guidelines for the use of bank‐stabilizing vegetation, and linking the effect of vegetation to geomorphic structure that can benefit ecosystem functioning. Copyright © 2014 John Wiley & Sons, Ltd.