Degree

Doctor of Oceanography and Coastal Sciences (POCS)

Department

Oceanography and Coastal Sciences

Document Type

Dissertation

Abstract

Alterations to Louisiana’s river systems and local hydrology have resulted in reduced freshwater, sediment, and nutrient inputs into wetland landscapes, causing significant negative impacts on marsh productivity and stability. To combat these losses many restoration projects have been constructed or planned throughout coastal Louisiana. Typical goals of wetland restoration efforts are to conserve, create, or enhance wetland form, and to achieve wetland function that approaches natural conditions. Failure to adequately maintain wetland elevation and hydrology can have serious implications on sedimentation and vegetation processes, which significantly reduces the likelihood of reaching structural and functional targets. Measures of wetland condition have been used to monitor and assess project performance, resilience, and adaptive management needs. This study assessed the use of remotely sensed and in situ data, in addition to landscape metrics (i.e., marsh area, edge density, and aggregation index) and vegetative indices (i.e., vegetation cover, normalized difference vegetative index, and floristic quality index) to evaluate changes and trends in restored wetland condition, function, and resilience, and compare those to naturally occurring reference wetlands. Results show that restoration measures (i.e., hydrologic restoration, wetland restoration, and beneficial use of dredge material) significantly increased wetland function (i.e., vegetation productivity, carbon sequestration, floristic quality), stability (i.e., increased marsh area, reduced loss rates, and increased spatial integrity), and resilience to disturbance events. Though many structural and functional measures (i.e., vegetation and landscape indices) of restored wetlands rapidly achieved equivalency to reference wetlands (approximately 3 to 5 years after construction), others, like some fundamental soil functions (i.e., carbon accumulation) required several decades to reach equivalency. These results demonstrated the importance of river connectivity and sedimentation for wetland productivity and overall spatial integrity. These studies show remotely sensing data and applications can significantly supplement traditional methods and provide critical knowledge elements for more efficient inventorying and monitoring of wetland resources, forecasting of resource condition and stability, and formulating adaptive management strategies.

Date

3-19-2018

Committee Chair

Sasser, Charles

DOI

10.31390/gradschool_dissertations.4504

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