Overall, the results of this study show that there are evident trends among the three ecoregions and delta of the White River. The forest stands of the Pine Ridge/Pierre Shale Ecoregion are the oldest along the river, as evidenced by aerial mapping going back into the 1930s and by the larger average trunk diameters of the trees. Historic aerial photographs for this ecoregion shows a relative static system from the 1930s-2010, with little destruction of existing or creation of new forests within the floodplain. Along with the older age of the forests, the stands in this ecoregion have the lowest floral diversity. The Pine Ridge/Pierre Shale forests are also unique along the river in that they are largely dominated by Acer negundo (box elder), a late-successional species that is largely absent from the forests of the other ecoregions. As the river continues downstream and enters the Badlands Ecoregion it gains size and volume, while its riparian forests decrease in patch size and tree density. Although the forests become smaller, the variety of communities and diversity of species increase. Unlike the Pine Ridge/Pierre Shale Ecoregion, the Badlands’ land cover was dynamic from the 1930s-2010, with increases in forest and declines in river channel area (-29%). Farther downstream and with a larger river channel, the River Breaks has even larger and more diverse riparian forests and the highest plant species richness and diversity among the ecoregions. The rate of land cover change was the greatest in the River Breaks, as the larger river has greater power for eroding existing communities and depositing sediment for recruitment. The area of riparian woody vegetation increased sharply from the 1930s-2010 (58%), while the area of channel declined (-20%). This ecoregion had the most perennial streamflow, with fewer zero flow days than in the upstream ecoregions. The Delta is unique as the only portion of the river where flows are affected by the Fort Randall Dam on the Missouri River. The impact of the reservoir on the area is evident, as it has the largest proportional area of forest along the river, as well as having the flora with the highest wetland affinity.
|Commitee:||Jarchow, Meghann, Sweeney, Mark|
|School:||University of South Dakota|
|School Location:||United States -- South Dakota|
|Source:||MAI 55/03M(E), Masters Abstracts International|
|Subjects:||Biology, Plant biology, Ecology|
|Keywords:||Floodplains, Great plains, Riparian ecology, Riparian forests, River systems|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be