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Population Genetic Analyses of the Baird's Pocket Gopher, Geomys brevicepsWelborn, Sarah 2012 August 1900 (has links)
The Baird’s pocket gopher (Geomys breviceps) is a solitary, fossorial rodent found throughout areas of Texas, Arkansas, Oklahoma, and Louisiana. Research focusing on the population genetics of pocket gophers and other species with limited vagility and isolated populations is lacking. Through the use of mitochondrial and microsatellite data, a series of population genetic analyses were completed to better understand the population structure and gene flow among a series of G. breviceps localities. Pocket gophers were captured from five localities in the Brazos Valley and used in this study. Due to the lack of microsatellite loci available for G. breviceps, 10 loci were created for use in this study. Overall estimates from the population genetic analyses showed high levels of gene flow amongst nearby localities with decreasing levels as distance between localities increased. Findings suggest that 2-3 localities located within 2 km of each other function as one genetic cluster thus showing 3-4 total genetic clusters total in this study. Results also suggest that the Baird’s pocket gopher is capable of moving at least 2 km, but further analyses should be completed to better understand dispersal distance.
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The Influence of Sea Surface Temperature, Chlorophyll Concentration, and Upwelling Index on Kogia Strandings in FloridaCordero, Vincent U. 01 November 2011 (has links)
It has been demonstrated that certain environmental fluctuations correlate with cetacean strandings in many parts of the world. I examined the correlations between three environmental variables (upwelling coefficient, temperature, and chlorophyll a concentration) and Kogia strandings in Florida from 1998 – 2007. In addition I examined the correlations between El Niño Southern Oscillation (ENSO) events and Kogia strandings in Florida and the southeastern United States (SEUS) from 1977-2007. Florida was divided into four regions and strandings were segregated by region with 76% of the strandings occurring on the east coast of Florida. AVHRR Pathfinder satellite temperature data, and MODIS Aqua and SeaWiFS satellite chlorophyll a data were downloaded from NASA websites; NOAA Fisheries Southwest Fisheries Science Center upwelling data were downloaded from the ERD Live Access Server, and ENSO data were also downloaded from a NOAA website. Upwelling was examined on a per stranding basis.
For each stranding, a square region (16 km x 16 km) of ocean adjacent to the stranding was examined for upwelling index values for the two weeks prior to the stranding (in increments of six hours). Each region was divided into 16 sub-regions (4 km x 4 km). For each increment of time the data were averaged over all 16 sub-regions. A significant change in upwelling index was defined as a change of absolute value greater than or equal to 200 m3/s/100 m of coastline. Of the 174 strandings, 91 (52%) were correlated to at least one significant upwelling event within 14 days prior to stranding.
I examined upwelling, temperature, and chlorophyll a concentration on a seasonal basis. The Florida coastline was divided into 16 regions. Each region was examined, for all three variables, out to approximately 32 km from shore. For each region the data were averaged for each month over the entire ten year study and compared to the number of strandings in each region each month. Data covering the regions of Florida were merged into four large regions (the east coast, the Keys, the west coast, and the Panhandle). I found an inverse correlation between chlorophyll concentration and strandings in Florida. In addition I found an inverse correlation between upwelling and strandings on the west coast of Florida. I examined the ENSO record from 1977 to 2007. I found a direct correlation between ENSO events and strandings in Florida (R2 = 0.1626) and the SEUS (R2 = 0.2236).
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