Browsing by Subject "Impacts"
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Item Assessing impacts of hydroelectric dams in the Amazon Fluvial Basin(2015-05) Wight, Charles Edward; Latrubesse, Edgardo; Arima, EugenioThe amount of water the Amazon River delivers to the Atlantic Ocean every day is enough to supply New York City's fresh water needs for 9 years. This is soon to change with the race to choke the Amazon Basin with large hydrologic dams. Although studies investigating single dams can provide great analysis on a couple key issues, they often fail to consider these effects on the systems entirety. Without linking the physical and social components, one fails to fully understand the impacts of hydroelectric dams and therefore the vulnerability of the basin. The focus of this study is based on three forms of investigation: 1. a comprehensive literature review including scholarship on hydroelectric dams, basis characteristics, protected areas, and political characteristics within the respective countries; 2. data procurement of the physical geography of 20 sub-basins, 1,100 tributaries, and land use-land change (LULC) data; and together 3. the creation of a multivariable database integrated with GIS (geographic information systems) in order to better interpret human/nature complexities. Combined, this database will be a powerful tool to assess vulnerability and risks associated with individual dams sites within a larger system. In addition, this database can be adjusted in the future such that when impacts of planned dams are actualized they can be recorded, and based of shared attributes of other dams in the database, this information can be correlated to make better predictions of new environmental and social impacts.Item Invasion risk and impacts of a popular aquarium trade fish and the implications for policy and conservation management(2014-05) Dugan, Laura Elizabeth; Hendrickson, Dean; Parmesan, Camille, 1961-Invasive species, a top threat affecting global biodiversity, become invasive through a process including four stages: transport, establishment, spread, impact and integration. Species currently in this process provide opportunities to empirically derive the mechanisms driving each of these stages, make predictions based on these mechanisms and then to test these predictions. This research examines the current invaded distribution, potential invasion and community-level impacts of a popular aquarium trade fish (Hemichromis guttatus Günther, 1862) in an endemic hotspot, Cuatro Ciénegas, in Coahuila, México and discusses the policy and conservation management implications of these findings. In Chapter 1, the problem of invasive species, the study site and the focal species of this work are introduced. In Chapter 2, the critical thermal minimum and maximum temperature limits and temperature preference of H. guttatus are identified because temperature is hypothesized to be an important factor controlling this fish’s distribution. The results indicate that H. guttatus has a wide temperature tolerance range (a characteristic of a ‘good’ invader), that preference is a more informative metric for predicting invasion than absolute tolerances, and that resource-poor environments may promote searching behaviors that cause an invasive fish to increase its range. In Chapter 3, the results of a field survey are analyzed and temperature, pH, depth and the presence of vegetation are all found to be related to H. guttatus presence. Invasion risk of several as-of-yet uninvaded sites in Cuatro Ciénegas is assessed. In Chapter 4, competitive and predatory interactions of H. guttatus on an endemic, threatened cichlid (Herichthys minckleyi) and a macroinvertebrate community respectively are investigated. The results suggest that while H. guttatus does not directly impact H. minckleyi through competition in these conditions, it may inhibit reproduction and alter H. minckleyi’s behavior through aggressive interactions. In Chapter 5, all results are synthesized and a determination of the invasive status of H. guttatus in Cuatro Ciénegas is made. The results presented here will be useful in identifying areas with a high risk of invasion by this popular ornamental fish, thus allowing the implementation of policy and management actions to prevent or at least ameliorate the impacts of an invasion and will add to the growing knowledge of how invasive species affect native systems.Item The impacts of technology on global unconventional gas supply(2009-06-02) Yanty, EviAs energy supplies from known resources are declining, the development of new energy sources is mandatory. One reasonable source is natural gas from unconventional resources. This study focus on three types of unconventional gas resources: coalbeds, tight sands, and shales. Whereas these resources are abundant, they have largely been overlooked and understudied, especially outside of North America. New technologies, including those needed to unlock unconventional gas (UCG) resources, have been acknowledged to be the most significant factor in increasing natural gas supply in the United States. This study evaluates advances in critical technology that will most likely increase supply the most. Advanced technology is one of the main drivers in increasing unconventional natural gas production, as observed in the United States, Canada, and Australia. 3D seismic, horizontal drilling, multilateral completion, water and gel based fracturing, coiled tubing rig, enhanced recovery, and produced water treatments are current important technologies critical in developing unconventional gas resources. More advanced technologies with significant impacts are expected to be available in the next decades. Fit-to-purpose technology reduces the cost to recover gas from unconventional resources. The better the unconventional gas resources are characterized, the better we can tailor specific technology to recover the gas, and less cost are needed. Analogy assumption is a good start in deciding which critical technology to be transferred to undeveloped unconventional reservoirs. If the key properties of two unconventional gas basins or formations are more or less similar, it is expected that the impact of certain technology applied in one basin or formation will resemble the impact to the other basin or formation.