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- All Subjects: biodiversity
Description
Habitat fragmentation, the loss of habitat in the landscape and spatial isolation of remaining habitat patches, has long been considered a serious threat to biodiversity. However, the study of habitat fragmentation is fraught with definitional and conceptual challenges. Specifically, a multi-scale perspective is needed to address apparent disagreements between landscape- and patch-based studies that have caused significant uncertainty concerning fragmentation’s effects on biological communities. Here I tested the hypothesis that habitat fragmentation alters biological communities by creating hierarchically nested selective pressures across plot-, patch-, and landscape-scales using woody plant community datasets from Thousand Island Lake, China. In this archipelago edge-effects had little impact on species-diversity. However, the amount of habitat in the surrounding landscape had a positive effect on species richness at the patch-scale and sets of small islands accumulated species faster than sets of large islands of equal total size at the landscape-scale. In contrast, at the functional-level edge-effects decreased the proportion of shade-tolerant trees, island-effects increased the proportion of shade- intolerant trees, and these two processes interacted to alter the functional composition of the regional pool when the total amount of habitat in the landscape was low. By observing interdependent fragmentation-mediated effects at each scale, I found support for the hypothesis that habitat fragmentation’s effects are hierarchically structured.
ContributorsWilson, Maxwell (Author) / Wu, Jianguo (Thesis advisor) / Smith, Andrew (Committee member) / Hall, Sharon (Committee member) / Jiang, Lin (Committee member) / Cease, Arianne (Committee member) / Arizona State University (Publisher)
Created2018
Description
Consumption of seafood poses a substantial threat to global biodiversity. Chemical contamination found in both wild-caught and farmed seafood also presents significant health risks to consumers. Flame retardants, used in upholstery, plastics, clothing, and other products to reduce fire danger, are of particular concern as they are commonly found in the marine environment and permeate the tissues of fish that are sold for consumption via multiple pathways. By summarizing various metrics of sustainability and the mercury content in consumed species of fish and shellfish, researchers have found that high levels of chemical contamination was linked with lesser fishery sustainability. I conducted a literature review of flame retardant content in seafood to further compare contamination and sustainability in addition to the initial analysis with mercury. My review suggests that the widespread issue of fishery collapse could be alleviated by demonstrating to stakeholders that many unsustainable fish stocks are mutually disadvantageous for both human consumers and the environment. Future research should address the need for the collection of data that better represent actual global contaminant concentrations in seafood.
ContributorsNoziglia, Andrea Joyce (Author) / Gerber, Leah (Thesis director) / Smith, Andrew (Committee member) / Pratt, Stephen (Committee member) / Barrett, The Honors College (Contributor) / Herberger Institute for Design and the Arts (Contributor) / School of International Letters and Cultures (Contributor) / School of Life Sciences (Contributor)
Created2014-05