Agricultural development has transformed the vegetation cover of many landscapes around the world, thereby altering water and sediment fluxes to river systems. Past work in the upper midwestern United States, particularly in areas of moderate relief, has shown that increases in water and sediment fluxes associated with agricultural development have dramatically altered river dynamics. Less is known about how agriculture has affected river dynamics, particularly rates of lateral migration, in relatively low relief landscapes of the Midwest shaped by glaciation during the Wisconsin Episode. This research examines rates of lateral migration of a channel bend along a lowland meandering river in Illinois, USA before and after agricultural development. The rate of lateral migration prior to agricultural development is estimated through dating of carbonaceous material within lateral-accretion deposits underlying distinct meander scrolls. The rate of lateral migration after agricultural development is determined from analysis of changes in river-channel position determined from survey records, aerial imagery, and digital elevation data. Average rates of migration before and after agricultural development are similar, suggesting that agricultural development has not substantially affected rates of lateral migration of the river. Some accelerated movement occurred locally following agricultural development, but this movement cannot be definitively tied to landscape transformation. Possible factors responsible for the lack of sensitivity of the river system to agricultural development include high resistance of the cohesive, tree-lined riverbanks to erosion and the low bankfull stream power per unit area of the modern river. From a management perspective, the study highlights the importance of bank vegetation in maintaining channel stability in low-relief agricultural landscapes.

中文翻译：

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蜿蜒低地河流对集约化景观管理的敏感性：流域规模农业开发前后的横向迁移率

农业发展改变了世界各地许多景观的植被覆盖，从而改变了河流系统的水和沉积物通量。过去在美国中西部上游地区，特别是中度地势地区的研究表明，与农业发展相关的水和沉积物通量的增加极大地改变了河流动态。关于农业如何影响河流动态，特别是在威斯康星期冰川作用形成的中西部相对低地势的景观中，人们对农业如何影响河流动态，特别是横向迁移率知之甚少。这项研究调查了美国伊利诺伊州农业发展前后沿低地蜿蜒河流的河道弯曲的横向迁移率。农业发展之前的横向迁移率是通过对不同曲流卷轴下方的横向增生沉积物中的碳质材料进行测年来估计的。农业发展后的横向迁移率是通过对调查记录、航空图像和数字高程数据确定的河道位置变化进行分析来确定的。农业发展前后的平均迁移率相似，表明农业发展并未对河流横向迁移率产生重大影响。农业发展后，当地发生了一些加速运动，但这种运动不能明确地与景观改造联系在一起。河流系统对农业发展缺乏敏感性的可能因素包括粘性的、绿树成荫的河岸对侵蚀的高抵抗力以及现代河流单位面积的全岸河流功率低。从管理角度来看，该研究强调了河岸植被在维持低地势农业景观河道稳定性方面的重要性。