The effect of a small vegetation dieback event on salt marsh sediment transport
The effect of a small vegetation dieback event on salt marsh sediment transport
复制标题
小植被枯死事件对盐沼沉积物输运的影响
DOI：
10.1002/esp.4547
复制
发表时间：
2018-12
影响因子：
3.3
通讯作者：
D. Coleman;M. Kirwan
中科院分区：
文献类型：
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作者：
D. Coleman;M. Kirwan
植被是生态地貌反馈的重要组成部分，使盐沼能够建立土壤和垂直生长。因此，植被枯死会对沼泽的稳定性产生有害影响，特别是在海平面上升的情况下。在这里，我们报告了各种泥沙输运测量与一个意想不到的，自然的枯死在一个快速扩张的沼泽在阿尔塔马哈河口，格鲁吉亚。我们发现，植被死亡率导致了显着的损失，海拔在枯梢病现场的垂直加积，侵蚀和表面地形的测量相比，植被参考区。地下植被死亡导致土壤抗剪强度降低。顶梢枯梢部位与参照部位相比，呈现侵蚀性、上凹的地形轮廓。在直接受枯梢影响的位置，悬浮泥沙浓度的洪水优势减少。我们的工作说明了如何植被干扰可以至少暂时扭转当地的轨迹的沼泽湿地，并产生复杂的沉积物输运模式。© 2018约翰威利父子有限公司
Vegetation is a critical component of the ecogeomorphic feedbacks that allow a salt marsh to build soil and accrete vertically. Vegetation dieback can therefore have detrimental effects on marsh stability, especially under conditions of rising sea levels. Here, we report a variety of sediment transport measurements associated with an unexpected, natural dieback in a rapidly prograding marsh in the Altamaha River Estuary, Georgia. We find that vegetation mortality led to a significant loss in elevation at the dieback site as evidenced by measurements of vertical accretion, erosion, and surface topography compared to vegetated reference areas. Below‐ground vegetation mortality led to reduced soil shear strength. The dieback site displayed an erosional, concave‐up topographic profile, in contrast to the reference sites. At the location directly impacted by the dieback, there was a reduction in flood dominance of suspended sediment concentration. Our work illustrates how a vegetation disturbance can at least temporarily reverse the local trajectory of a prograding marsh and produce complex patterns of sediment transport. © 2018 John Wiley & Sons, Ltd.