Collaborative Research: Modeling the Impacts of Post-Settlement Sediment Deposition on Floodplain Vegetation

[05:59 . 29]汤森温带河流系统及其相关洪泛平原已被人类活动大大改变。虽然水坝对河流水文和下游生态系统的影响已经被广泛研究，但关于历史沉积制度和地貌变化如何影响洪泛平原生态系统的数据实际上是不存在的。本研究将展示整个模型河流系统（北卡罗来纳州的罗阿诺克河）由于沉积物沉积而导致的后殖民景观尺度生态系统改变的程度，以及未来的变化可能影响植被动态，因为这些沉积物被重新分配和运输出系统。我们将测试一系列具体的假设，主要集中在以下几个方面：(1)在过去的250年里，在罗阿诺克河漫滩上的人为沉积物沉积导致了地貌系统内地貌的范围和分布的剧烈变化；(2)由于后殖民时期沉积造成的地貌变化，环境发生了变化，使得罗阿诺克河漫滩下游的植被发生了很大的变化；(3)基于地貌和古生态数据建立的泥沙侵蚀河岸区模型可用于预测未来地貌和植被组成。为了解决这些假设，我们将整合树木地貌学、孢粉学和建模技术，以：(1)为罗阿诺克河下游河漫滩建立一个殖民后沉积物积累的空间明确模型，(2)模拟殖民前的地貌景观并模拟未来的河漫滩地貌，以及(3)利用植被-环境关系预测这些表面的植被分布。

0105929TownsendTemperate river systems and their associated floodplains have been substantially altered by human activity. Although the effects of dams on river hydrology and downstream ecosystems have been studied extensively, data on how changes in historic sedimentation regimes and geomorphology affect floodplain ecosystems is practically nonexistent. This research will demonstrate for an entire model river system (the Roanoke River of North Carolina) the degree of post-colonial landscape-scale ecosystem alteration due to sediment deposition, and the future changes likely to affect vegetation dynamics as those sediments are redistributed and transported out of the system. We will test a series of specific hypotheses centered on the following: (1) Anthropogenic sediment deposition on the Roanoke River floodplain over the last 250 years has led to a dramatic alteration of the extent and distribution of landforms within the geomorphologic system; (2) The vegetation of the lower Roanoke floodplain has been substantially altered as a consequence of environmental changes due to geomorphic alterations from post-colonial sedimentation; (3) Models of sediment-impacted riparian areas developed from geomorphologic and paleoecological data can be used to predict future landforms and vegetation composition. To address these hypotheses we will integrate dendrogeomorphic, palynological and modeling techniques to (1) develop a spatially explicit model of post-colonial sediment accumulation for the lower Roanoke River floodplain, (2) model the pre-colonial geomorphic landscape and simulate future floodplain geomorphology, and (3) predict vegetation distributions for those surfaces using vegetation-environment relationships.