Identifier

etd-06232015-115007

Degree

Master of Science (MS)

Department

Oceanography and Coastal Sciences

Document Type

Thesis

Abstract

Saltmarshes are under continuous multiple stressors such as, land loss, erosion, climate change, environmental pollutions and oil spills, which affect the ecological communities inhabiting saltmarshes. Terrestrial arthropods play an important role in the ecology of saltmarshes, affecting primary production and decomposition. Arthropods are often found in the gut contents of Seaside Sparrows and fishes making them an important trophic link to terrestrial and marine vertebrates. Insects and spiders have the potential to be a good indicator of overall marsh health and environment as they are differentially sensitive to oil exposure. Oil pollutants may have significant long-term negative impacts on the terrestrial arthropods and consequently the food web. Ten sites along the coast of Louisiana were sampled: 3 lightly-oiled, 4 heavily-oiled sites in Barataria Bay, and 3 reference unoiled sites in Delacroix, St. Bernard Parish northeast of Barataria Bay, to determine the impacts of the Deepwater Horizon oil spill on the Louisiana saltmarsh terrestrial arthropods. Insects were collected via sweep net, 20m inland from the shoreline monthly between April and June of 2013 and 2014. Orthoptera, Hemiptera, Diptera, Thysanoptera, and Araneae were the most abundant groups of arthropods found at most sites. Species richness was significantly higher (P < 0.05) in references sites than lightly-oiled and heavily-oiled in both years. Shannon Weaver Index was similar in all sites, but higher in 2014 than 2013, suggesting a positive recovery of terrestrial arthropods’ communities. Higher number of arthropods were observed in 2014 than 2013. Odonata were significantly higher in reference sites in both years. Orthoptera significantly increased in 2014 at all sites. Herbivores, Delphacidae populations increased in 2013 in response to the stress on plants due to Hurricane Isaac. Araneae were higher in oiled sites in 2013, but in 2014 the Araneae increased in reference sites, whereas they decreased in oiled sites. Overall, the terrestrial arthropods were affected by the oil and Hurricane Isaac. The oil contamination effects still persist today. Although the slow recovery of certain terrestrial arthropods was observed, long term monitoring of arthropod communities would help better understand the recovery and succession of the marsh ecosystem.

Date

2015

Document Availability at the Time of Submission

Secure the entire work for patent and/or proprietary purposes for a period of one year. Student has submitted appropriate documentation which states: During this period the copyright owner also agrees not to exercise her/his ownership rights, including public use in works, without prior authorization from LSU. At the end of the one year period, either we or LSU may request an automatic extension for one additional year. At the end of the one year secure period (or its extension, if such is requested), the work will be released for access worldwide.

Committee Chair

Hooper-Bui, Linda M

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