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Description
Use of off-highway vehicles (OHV) in natural landscapes is a popular outdoor activity around the world. Rapid-growing OHV activity causes impacts on vegetation and land cover within these landscapes and can be an important factor in land degradation and ecosystem change. The Algodones Dunes in southeastern California is one of the largest inland sand dune complexes in the United States and hosts many endangered species. This study examines changes in land cover and OHV activity within two OHV active sites in comparison to an adjoined protected area. The study also investigates potential associations between land cover changes, climate trends, and OHV activity over recent decades. Time-series analysis was used to investigate the spatial-temporal changes and trends in the land cover in the Algodones Dunes from 2001 to 2016. In addition, high-resolution aerial photographs were analyzed to determine spatial patterns of OHV usage in comparison to visitor estimation collected by the Bureau of Land Management and observed changes in land cover composition between the control site and OHVs areas.
A decreasing trend in Normalized Difference Vegetation Index over time indicates a decline in the amount of vegetation cover, which corresponds with an increasing trend in albedo and land surface temperature. Results also show a substantial difference in land cover between the control site and OHVs areas, which typically have a lower amount of vegetation cover, higher exposed sand surface, and increased anthropogenic features. Both climatic variations and OHV activity are statistically associated with land cover change in the dune field, although distinct causal mechanisms for the observed declines in vegetation cover could not be separated. The persistence of drought could inhibit vegetation growth and germination that, in turn, would hinder vegetation recovery in OHV areas. Meanwhile, repeated OHV driving has direct physical impacts on vegetation and landscape morphology, such as canopy destruction, root exposure, and increased aeolian sand transport. Active ecosystem protection and restoration is recommended to mitigate the response of declining vegetation cover and habitat loss to the impacts of OHV activity and climatic variability and allow natural recovery of re-establishement of nebkha dune ecosystems in the Algodones Dunes.
A decreasing trend in Normalized Difference Vegetation Index over time indicates a decline in the amount of vegetation cover, which corresponds with an increasing trend in albedo and land surface temperature. Results also show a substantial difference in land cover between the control site and OHVs areas, which typically have a lower amount of vegetation cover, higher exposed sand surface, and increased anthropogenic features. Both climatic variations and OHV activity are statistically associated with land cover change in the dune field, although distinct causal mechanisms for the observed declines in vegetation cover could not be separated. The persistence of drought could inhibit vegetation growth and germination that, in turn, would hinder vegetation recovery in OHV areas. Meanwhile, repeated OHV driving has direct physical impacts on vegetation and landscape morphology, such as canopy destruction, root exposure, and increased aeolian sand transport. Active ecosystem protection and restoration is recommended to mitigate the response of declining vegetation cover and habitat loss to the impacts of OHV activity and climatic variability and allow natural recovery of re-establishement of nebkha dune ecosystems in the Algodones Dunes.
ContributorsCheung, Suet Yi (Author) / Walker, Ian J (Thesis advisor) / Myint, Soe W (Committee member) / Dorn, Ronald I. (Committee member) / Arizona State University (Publisher)
Created2018
Description
The purpose of this research was to address the viability of a monoculture to polyculture agricultural land-cover transition within the context of the palm oil industry in Malaysia and Indonesia. A lifecycle assessment was used as a framework in the Cradle-to-Gate methodology used to understand sustainability hotspots, develop four future scenarios, and to measure three chosen indicators for metric changes. The four scenarios included a business-as-usual, perfect world, and two transition scenarios highlighting greenhouse gases, bio-control chemicals, fertilizer-use, and crop yield as indicators. In the four scenarios, a 1000 ha of plantation land with 140,000 palm oil trees created the backdrop for investigating nutrient cycling, cultivation methods, and the economic trade-offs of a transition. Primary literature was the main source of investigation and a wide-variety of current polyculture research helped create tangible data across the four scenarios. However, polyculture failed to address the socioeconomic barriers present in the governance, business-state, and regulations within this industry and region. An institutional analysis was conducted to investigate the political, financial, and regulatory barriers in this industry and recommend changes. It was concluded that while polyculture is an important form of environmental sustainability and can increase crop yield, the socioeconomic structure of the industry is the largest barrier to change and implement polyculture. In order for this social structure to change, it was recommended that the regulatory institutions, such as the Roundtable for Sustainable Palm Oil (RSPO), reframe their pressure points and instead focus on the interconnectedness of logging and palm oil companies with the regional governments.
ContributorsPhillips, Katherine Wasem (Author) / Clark, Susan (Thesis director) / Shrestha, Milan (Committee member) / School of Sustainability (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05