Use of ddRAD-sequencing to diagnose cryptic species with low interspecific mitochondrial divergence

Sister species that have diverged from each other recently can appear similar morphologically but typically have genetic features that can distinguish them due to a lack of gene flow. In the case of two sympatric species of bat (Myotis californicus and M. ciliolabrum) that are cryptic, they can be distinguished by features of their echolocation call, but no genetic marker has been discovered that can easily distinguish them. A simple diagnostic genetic marker, like a DNA sequence barcode, would assist researchers to identify species from wing punches or fecal pellets from a roost without the need to collect the bat. Despite research on their mitochondrial genome from specimens across their range, a barcoding approach does not seem to work for this complex. We tested the hypothesis that these two species can be diagnosed using a genomic approach. We used reduced representation genome sequencing (ddRAD-seq) to identify and analyze single nucleotide polymorphisms (SNPs) from individuals of M. californicus and M. ciliolabrum. Using principal component analysis, population structure analysis, and a RAxML phylogenetic tree, we found that the samples formed three distinct groups rather than the two we expected. We found more cryptic biological diversity than expected within the morphologically-similar complex. The two clusters recovered within M. ciliolabrum appear to be consistent with previously recognized subspecies

Bat community composition and post-departure degradation patterns of airborne eDNA shed by migratory cave bats

Leptonycteris nivalis (Mexican long-nosed bat) is an endangered species of nectivorous bat known to seasonally occupy Emory Cave in Big Bend National Park, Texas, USA. The endangered status of L. nivalis necessitates regular assessments of population size, habitat use, and roosting behaviors. However, disturbances by researchers may have a negative impact on bat species. In recent years it has been shown that it is possible to characterize a terrestrial vertebrate community using environmental DNA (eDNA) collected from the air, particularly in an enclosed environment such as a cave. Recent studies have surveyed roosts occupied by a small number of bats but have yet to do so in a high-occupancy, high fidelity roost or when a roost has been vacated by the target species. Our objectives were to use airborne eDNA samples from Emory Cave to evaluate eDNA retention inside a bat roost over time and to characterize the bat community inside the cave. We hypothesized that even in their absence, airborne eDNA samples would be able to detect L. nivalis at Emory Cave and identify other species utilizing this roost site. We identified DNA from four bat species, five non-bat mammal species, and two bird species known to use the habitat around the cave. Our results suggest that the amount of eDNA recovered was not related to the length of time since departure of the target species (P = 0.4) but was related to the depth at which samples were collected (P = 0.0002) and the placement of samplers within the roost (P < 0.001). We were able to detect L. nivalis DNA inside the cave 255 days after the bats had vacated the roost, demonstrating the extreme sensitivity of this method. These results indicate that airborne eDNA sampling can provide useful information about cave-roosting species. We recommend further research into the environmental factors that affect airborne eDNA retention and collection in a cave environment

Preserving history: conservation research and treatments on two 1930s oil paintings

Works of art are more often viewed as aesthetic objects than historical documents, but they can in fact provide a unique and direct window into the values, biases, and ideas of a past time. Preserving these artifacts is a way to ensure that future generations can learn from the past just as we can. History, chemistry, artistry and ethics must all be considered to understand how best to bring a damaged painting back to life so that it can once again serve as a window to the past. Throughout the Fall 2024 and Spring 2025 semesters, I partnered with the Fort Concho Museum of San Angelo through the Angelo State University Honors Program to perform conservation treatments on two 1930s oil paintings in the museum's collection. This thesis will cover the conservation and restoration of these paintings, discussing the research behind each of the necessary conservation treatments and how they were tested and applied for this project. Treatments performed on the paintings included surface cleaning, removal of foreign material, infilling, and inpainting. I will also discuss my research into how these paintings fit into local history and the art world as a whole, and why their preservation is important

Harsh and harsher: intertwining environmental challenges faced by late 19th century Texas frontier forts

This thesis examines how the environment created challenges for post-Civil War frontier forts in Texas and argues that many of these challenges were both intertwined and compounded each other. It uses the medical histories of Forts Richardson, Davis, Concho, McKavett, Griffin, and Stockton, where information regarding water supply, disease, post garden success, and weather was recorded down on a monthly basis. Secondary sources have been used to supplement these primary sources where there are gaps in the historical record or limits to historical knowledge regarding disease and other environmental challenges. While the problems the environment caused for the forts have been acknowledged in previous literature and research, the intertwining nature of these challenges and the importance of their existence has rarely been focused on. This thesis examines the environmental challenges for all Texas frontier forts and how the different environmental factors interacted with each other