Population Biology Commons^™

An Ecological Survey Of East Texas Salamanders Across The Camp Tyler Outdoor Field School In Smith County, Texas, Justin C. Hunt

Biology Theses

Amphibians are a unique class of organisms with a very long and storied evolutionary history of survival. Many modern amphibian clades occupy several vital ecological roles within their native freshwater environments. One of these roles, typically includes functioning as an ecological indicator species, whereby the presence of stable and diverse populations of many amphibian species, including salamanders, within a freshwater ecosystem have long been considered ecological indicators of good habitat quality and stable ecosystem health. Similarly, salamanders also function as important members of their local food webs and act as valuable mediators of complex trophic hierarchies to facilitate nutrient cycling …

Ecological Analyses Of Macroinvertebrates And Fish Species In Six Streams On A Louisiana Military Base From 2001 To 2019, Danielle Joerger

Biology Theses

An in-depth ecological analysis of how and why the aquatic community changes over time was conducted for 6 streams on the Fort Polk military base in Louisiana using data collected from 2001 to 2019. Fort Polk is a unique location as nineteen first-order streams are located on the premises belonging to three separate drainages. The primary goal was to determine whether temporal or between-drainage variation has a larger effect on community structure. To accomplish this the effects of disturbance on fish and macroinvertebrate assemblages was determined temporally and between drainages. Several hypotheses were drawn from this: 1) temporally, assemblages exhibit …

Diatom Voucher Flora And Comparison Of Collection Methods For Biodiversity Hotspot Upper Three Runs Creek, Katie M. Johnson

Biology Theses

Surface freshwater is a scarce resource. Due to the scarcity and necessity of this resource, it is imperative that its quality is routinely monitored. One way of monitoring water quality is through biological assessments, which include examining algal assemblages. Regionally, little remains known of algal taxa in the southeastern United States. In the past, the Academy of Natural Sciences of Philadelphia (ANSP) conducted biological assessments along the Savannah River finding Gomphonema parvulum (Kützing) Kützing 1849 to be a dominant taxon rendering assessments inconclusive. Recent studies have provided evidence that species complexes and semi-cryptic taxa have been identified within the Gomphonema …

Assessing Population Genetic Structure Of Eastern Phoebes At A Migratory Stopover Site, Daniel Jones

Biology Theses

Migration is an energetically costly and stressful event and migratory stopover sites are important areas along the migratory route that birds stop at to rest and refuel. Migration timing and routes vary across and even within species, including differences between sexes, ages and populations. Most genetic studies of migratory birds occur on breeding grounds, but when breeding locations are not known, it is likely that genetic patterns can be assessed accurately at migratory stopover sites if certain conditions exist. First, if a species is philopatric – where individuals return to the same sites every year, gene flow across geographically separated …

Population Structure, Demographic History, And Environmental Niche Of The Sand Fly Disease Vector Lutzomyia Shannoni (Dyar) (Diptera: Psychodidae) In The U.S., Mexico, And Colombia, Matthew E. Wolkoff

Biology Theses

Lutzomyia shannoni (Dyar, 1929) (Diptera: Psychodidae) is the only known sand fly vector of vesicular stomatitis virus, a putative leishmaniasis vector, and also boasts the widest distribution of any sand fly in the New World. Research on Lu. shannoni in Central and South America has revealed genetically divergent subpopulations; however, tentative analysis of Lu. shannoni in the U.S. has failed to detect any significant population structure, even between specimens collected from highly disparate localities.

The present study used four molecular markers to more closely investigate the population structure of Lu. shannoni in the U.S., and assess the species’ relationships with …

Phylogenetic And Ecological Analysis Of Two Populations Of The Kitsatchie Painted Crayfish, Orconectes Maletae (Decapoda: Cambaridae), Larrimy Beth Brown

Biology Theses

The primary aim of this study was to assess the conservation status of the East Texas population of the Kistachie Painted Crayfish, Orconectes maletae. Orconectes maletae has been given a Global Heritage Ranking of G2, or imperiled, because of population declines in the Kisatchie Bayou drainage in Louisiana; however, similar data for Texas is lacking. For the current study, surveys of 25 historical sites in Texas were conducted in the Cypress Creek and Caddo Lake drainage from June to August 2014 and revealed that O. maletae was either absent or in low enough abundance to evade detection at close …

An Analysis Of Morphometric Differentiation In Lake And River Populations Of The Emerald Shiner, Notropis Atherinoides, John J.V. Lang

Biology Theses

Understanding mechanisms that account for phenotypic variation has been of interest to biologists since the advent of Darwin’s theory of evolution by natural selection. It is now understood that adaptive divergence is a key driving force of intraspecific differentiation. Further, differences in habitat (e.g., flow regime, prey regime) have been shown to drive adaptive divergence in fish. For instance, fish inhabiting faster flowing water generally exhibit more fusiform bodies than their lake counterparts. Similarly, the partitioning of benthic and pelagic morphs generally results in smaller heads with the latter. This study used geometric shape analysis to assess morphological differences between …

Population Dynamics And Genetic Differentiation Of The Threatened Freshwater Mussel Species Fusconaia Askewi, Fusconaia Lananensis, And Pleurobema Riddellii, Edith D. Plants-Paris

Biology Theses

North America has the most diverse freshwater mussel fauna in the world with approximately 300 species; unfortunately, extinction rates for freshwater mussels rivals the rates of many other groups of organisms. Population-level natural life history data is essential in the management of species of conservation concern, yet basic information about freshwater mussel life-history and demographic traits are unknown for many species. To further complicate matters, taxonomic uncertainty exists among some members of the group. The work detailed herein had two goals: to gain further understanding of the taxonomic relationship between Fusconaia lananensis and F. askewi by sequencing genes that had …