Ecotones provide an ideal setting to understand and evaluate how ecosystems will respond to changing climates because these dynamic areas where two ecosystems meet are delineated by factors that will be influenced by climate change. In the Northern Gulf of Mexico, salt marshes and mangrove forests are present in tidal saline wetlands and where temperate and tropical conditions meet, thus forming an ecotone. As a result of increasing minimum winter temperatures, mangroves are expected to expand their range at the expense of salt marshes, which could impact the provision of some ecosystem goods and services. To determine how ecological processes may be affected by mangrove expansion and development, I compared plant-soil interactions across mangrove structural gradients in three locations, one in each of the following three locations: Texas, Louisiana, and Florida. These three locations are found in areas with distinct abiotic and biotic factors. At each location, I sampled three salt marsh sites and nine different mangrove sites that spanned the respective mangrove forest structural gradient, utilizing height as my criterion. At each site, I quantified plant community composition and structure, soil physicochemical/porewater properties, and hydrological/climatic conditions. The results revealed differences in the local structural gradients among the three locations, resulting from regional variations in major abiotic factors. Of the three locations, mangrove forest development in Texas exerted the largest impact on properties related to soil quality (eg. increased accumulation of soil organic matter, carbon, nitrogen). In contrast, Florida mangrove forest development was associated primarily with increased soil organic matter, whereas few effects of mangrove forest development were detected in Louisiana. These findings illustrate the importance of considering site history and environmental conditions when attempting to predict climate-mediated responses of coastal plant communities, their impacts on soil properties and processes, and the implications on the provisions of ecosystem services.
|Advisor:||Hester, Mark W.|
|Commitee:||France, Scott C., Krauss, Ken W., Leberg, Paul L., Osland, Michael J.|
|School:||University of Louisiana at Lafayette|
|School Location:||United States -- Louisiana|
|Source:||MAI 54/04M(E), Masters Abstracts International|
|Subjects:||Ecology, Climate Change, Biochemistry|
|Keywords:||Climate change, Ecotone, Gulf of mexico, Mangrove, Salt marsh|
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