Freshwater ecosystem degradation in the Amazon and Orinoco river basins is increasing due to rising human population numbers, and large water development projects. Therefore, monitoring ecosystem condition in these rivers of high biodiversity is of global conservation importance. This dissertation evaluated the potential of using river dolphins as indicators of ecosystem condition in large tropical rivers of South America. First, population estimates of river dolphins were obtained by line-strip transect surveys and mark-recapture methods on photo-identifications. Using this information, I identified critical habitat, hotspots, and areas of concern for river dolphins, as well as the relationship between dolphin density and group size estimates with ecological features. Second, I evaluated the relationship between dolphin estimates and human stressors. Higher densities of dolphins occurred in rivers with low indices of overall freshwater degradation, such as rivers with high water quality and the lowest human population numbers. Thus, dolphin density estimates seem to be good indicators of freshwater ecosystem degradation in the Amazon and Orinoco basins. These top predators not only are indicator species, but also have the potential to act as flagship and sentinel species, indicating freshwater ecosystem degradation and stimulating conservation action. This dissertation highlights the large changes in the Amazon and Orinoco that are approaching fast. Indicator, flagship and sentinel species can become science-based conservation tools not to only document freshwater ecosystem degradation, but to raise awareness about broader implications of human stressors on biodiversity and river systems.

As the corporate world, communities, and individuals become more globalized and demands on natural resources increase, a new emphasis on environmental leadership including a new pragmatic environmental ethos is needed to meet certain basic human needs of future generations. The research problem addressed in this study was the lack of knowledge concerning how environmental cognitive dissonance influences consumption practices related to inefficient resource utilization and ecosystem degradation. The purpose of this study was to provide an understanding of the breadth and depth of environmental cognitive dissonance among visitors to the Kruger National Park in South Africa. The research questions addressed the development, manifestation, and mitigation of environmental cognitive dissonance. This qualitative case study was designed for a purposeful sample of 12 participants visiting the Kruger National Park, South Africa. Data were collected via structured interviews, field observations, and questionnaires, and then were analyzed using a data spiral and cross case analysis. The dominant findings indicated that (a) awareness of personal values, culture, and perceptions of the environment were responsible for basic attitudes regarding the environment and consumption; (b) wasteful habits, excessive consumption, and market influences were juxtaposed with nostalgic/episodic memories and deep thoughts about personal consumptive habits; and (c) an interactive multisensory experience in a pristine and wild environment changed perceptions and values regarding ecosystems and ecosystem preservation. The results of this study could help stewards of natural resources develop a new understanding of consumptive behavior and a new consumer ethos of stewardship and environmental leadership, one that inspires healthy and sustainable ecosystems.