Graduation Year

2021

Document Type

Thesis

Degree

M.S.

Degree Name

Master of Science (M.S.)

Degree Granting Department

Geography, Environment and Planning

Major Professor

Gregory S. Herbert, Ph.D.

Co-Major Professor

Steven Reader, Ph.D.

Committee Member

Stephen P. Geiger, Ph.D.

Keywords

conservation, gastropod, Multivariate regression, Shannon index

Abstract

Biodiversity is essential to the ecosystem functions responsible for generating the multi-billion-dollar industries that the US relies on for food, storm mitigation, tourism and recreation, but is facing increasing natural and anthropogenic threats. High-resolution diversity data covering large spatial areas would enhance current ecology knowledge and better address conservation concerns in the Gulf of Mexico. However, acquiring and handling data of this nature is resource intensive and has not yet been established. In this study, high spatial resolution data was collected from gastropod living and death assemblages collected over 10 years from the West Florida Shelf (WFS). A multivariate regression model was used to predict and map diversity across the WFS. A total of 137 stations met the minimum sample size of 10 individuals and provided an abundance matrix of 14,366 individuals across 256 species for this analysis. Parameters used to estimate and predict Shannon diversity index (H’) were bathymetry, sediment type, distance to the coast, distance to the closest major river, chlorophyll-a, and latitude. No significant relationship between diversity (H’) and distance to the coast, chlorophyll-a, or latitude was detected by the model. Bathymetry was the most important variable, and it was found to have a non-linear relationship with H’. Diversity was highest in the south of the study area and in the middle of the shelf, and generally found lowest in the north, along the coast and westernmost extent of the study area. Some areas of high diversity overlap with previously established marine protected areas such as the Dry Tortugas and Pulley Ridge, but these zones do not protect several major areas of high diversity. This work establishes the first comprehensive starting point to construct baseline data for the Gulf of Mexico and will be used to better inform fishery managers and conservation efforts as the frequency and intensity of natural and anthropogenic stressors continue to increase.

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