Hydro-dams provide many benefits, but can also adversely affect ecosystems and society. Given that dams have influences at large scales, the impacts of dams are so complicated that it is difficult to make accurate estimates of results from dams. Three basins in Southeast Asia, the Mekong, Salween, and Irrawaddy Basins, have recently constructed hydro-dams, but their impacts on ecosystems and society remain poorly characterized due to insufficient monitoring systems, poor economic status, and complicated international relationships of the region. The spatial impacts of dams can represent the dam-related events on ecosystems and society. Given the heterogeneity of the spatial impacts of dams, understanding the impacts of dams at multiple scales can make a better estimate for better policies for Southeast Asia. In this dissertation, I employed novel remote sensing approaches to quantify the spatial impacts of dams on ecosystems and society using a multi-scale perspective. The specific objectives were: (1) to quantify the site-based spatial impacts of dams on land systems, (2) to characterize the watershed-scale spatial impacts of dams on wetlands, and (3) to determine the distant impacts of dams on watersheds.The results in this dissertation quantified the spatial heterogeneity of dam impacts on ecosystems and society according to the spatial scales, locations, and distances. Specifically, analyses in this dissertation led to three major findings. First, the spatial impacts of dams in the on-site based scale were quantified, and the different spatiotemporal impacts of dams on land systems according to dam stages were found. Second, the spatial impacts of dams on wetlands in watershed-scale were characterized by distinguishing the influences from local human activities and climate variability on wetland inundations. This showed how dams affect wetlands differently according to the location (upstream / downstream) and distance (close / far) in watersheds. Third, the distance and areas of the spatial impacts of dams on watersheds were determined. This found the anisotropic spatial patterns of the distant effects of dams on upstream and downstream watersheds. Therefore, this dissertation highlights the benefits of geographical perspectives and spatial information in understanding the consequences of dams which are complicated interactions between humans and the environment.
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