Current Research

In recent years, rising sea levels and saltwater intrusion have impacted coastal habitat composition in the Gulf of Mexico, potentially reducing the reproductive fitness of native species unadapted to briney environments. The Common Nighthawk (Chordeiles minor) is an aerial insectivore that nests on open grounds along the beaches of the Gulf Coast. Between 1966 and 2019, C. minor had a cumulative population decline of 48%, dropping 1% each year. My study aims to combine field samples with museum specimens to study temporal change in trophic ecology via stable isotope signatures over the last century. My study will include ~94 feather samples that span the dates of 1937–2022. I will collect data on δ15N, δ13C, and δ34S isotopic ratios to provide an integrative perspective on the trophic ecology and habitat use of C. minor by tracing primary producers, trophic level, and salinity content of food webs respectively. This is an ongoing project, and as we begin analyzing our data, I hypothesize that historical specimens will carry a different isotopic signature from contemporary samples, indicating temporal change in the trophic ecology of C. minor and food webs of the Gulf Coast. I will build upon this study by testing for loss of genomic diversity through time in Gulf Coast populations of C. minor due to their steep decline using a combination of historical and contemporary blood and tissue samples. These data will inform future conservation initiatives by providing an understanding of how this coastal breeding population is adapting to this changing environment.

Cancer Alley, an 85-mile stretch of the Mississippi River in Louisiana, is home to over 150 oil refineries, petrochemical plants, and plastic manufacturing plants. Since its initial development in the 1940s, over 1000 known chemicals have been documented poisoning the region's air and waterways. However, few studies have been conducted analyzing heavy metal contamination in this region. In Cancer Alley, lead (Pb) pollution is a by-part of both gas production and plastic stabilizers used for Polyvinyl chloride (PVC) manufacturing. For conservationists, lead pollution in the region raises concern about the risk of lead toxicosis for thousands of native bird species who inhabit the Mississippi Delta during breeding and non-breeding seasons. Since lead substitutes calcium and accumulates in bones, bone lead concentration can serve as a biomarker of cumulative lifetime lead exposure of avifauna in Cancer Alley. Using X-ray fluorescence-a novel, non-destructive technique which uses emission patterns from X-rays to characterize the chemical composition of a given subject-our study analyzes temporal trends of tibiotarsus lead concentration (µg/g) of 102 Red-winged Blackbird (Agelaius phoeniceus) specimens collected in Cancer Alley between 1935 and 2022. We examine lead concentration of specimens over time in light of changing environmental policy and consider the utility of natural history collections for studying ecotoxicology over time and space.

The Gulf Coast of the United States is one of the most ecologically dynamic marine regions in the world, providing critical habitat to thousands of native species during breeding and non-breeding seasons, or as stop-over sites in migration. Gulf ecoregions support large populations of breeding obligate marsh, urban, and marine bird species who differ in core aspects of their natural history, such as diet and habitat preferences. Bird’s habitat specialization, in addition to spatial constraints of suitable nesting areas, has been documented limiting avifauna’s ability to move between habitat patches in different coastal regions throughout the United States. Studies analyzing the population structure of Gulf breeding birds have been limited, and thus far, we do not fully understand the interplay of how life history, biogeography and evolutionary history affect population structure in avifauna nesting the Gulf’s ecoregions. Using a comparative phylogeographic approach, I will collect genomic data to compare the evolutionary histories of several species of birds that breed throughout the Gulf's ecoregions. By inferring population structure, levels of gene flow, and demographic history of Gulf-associated birds, I will test the following hypotheses: 1) The Gulf of Mexico serves as a barrier to dispersal, limiting gene flow between populations found in Texas and Florida. 2) Species that differ in their degree of habitat and diet specialization within Gulf ecoregions will show different evolutionary histories. I am still identifying potential focal taxa for this project, and I am looking for collaborators who can assist me in sample acquisition.