Projects

Understanding Waterbird Habitat Relations with Antebellum Rice Fields Using Unpiloted Aerial Vehicles (UAVs) and Autonomous Recording Units (ARUs) in Coastal South Carolina

Akshit Suthar

Globally, humans have modified millions of acres of wetlands to grow rice for consumption. Rice culture in the southeastern United States began in the 1670s; was primarily successfully developed, managed, and driven by the labor of enslaved persons; and ended with the U.S. Civil War. During this time, humans transformed tidal swamps and hardwood bottomland forests into highly managed farming systems. These systems left behind a legacy of land use when abandoned after slavery. Today, there are almost 236,000 acres mapped as antebellum rice fields in nine coastal counties of South Carolina. Over half have been abandoned or are no longer wholly impounded. The remainder is managed mainly for wintering waterfowl and is owned privately or as public land.

An average of 27% of all dabbling ducks in the Atlantic Flyway winter in the South Atlantic region, particularly in South Carolina. Rare and endangered species, including Wood Storks (Mycteria americana), American White Pelicans (Pelecanus erythrorhyncho), and Roseate Spoonbills (Platalea ajaja), use antebellum rice field impoundments as wintering grounds. These impoundments also support the highest counts of Black Rails (Laterallus jamaicensis) along the Atlantic Coast. Environmental forces that have been influenced by climate change are causing increased degradation and loss of the antebellum rice field infrastructure.

The conservation of antebellum rice fields presents a complex challenge, with questions about whether they should be preserved for their cultural significance, restored to their pre-agricultural state, or managed as wildlife habitats. There is also debate about the impact of impoundments on coastal wetlands and waterbird habitats, with some scientists arguing that managed impoundments are more beneficial than unmanaged tidal marshes. In contrast, others claim that waterbirds would use tidal wetlands if impoundments did not exist.

Objectives of our study are to 1) Quantify the abundance and occupancy of waterbirds in antebellum rice fields; 2) Evaluate waterbird habitat association using wetlands characteristics such as percent open water, vegetation patterns, and composition to understand the benefits of managed and unmanaged antebellum rice field impoundments; 3) Determine waterbird habitat suitability across antebellum rice fields using environmental modelling; and 4) Evaluate the effectiveness of Unpiloted Aerial Vehicles (UAVs), Autonomous Recording Units (ARUs), and Artificial Intelligence (AI) tools in detecting and quantifying waterbirds in antebellum rice fields.

Overall, our study aims to understand the waterbird-habitat relationship with antebellum rice fields comprehensively. This will inform evidence-based management decisions for the conservation and management of these important habitats, as well as the role of technology in wildlife research and conservation.

Ecotoxicology of Microplastics and Per- and Polyfluorinated Substances in the American Alligator (Alligator mississippiensis)

Miriam Boucher

Human-introduced contaminants, including per- and polyfluorinated substances (PFAS) and microplastics, pose risks to water resources. PFAS are a large class of synthetic fluorinated organic chemicals with carbon-fluorine bonds. This group of chemicals is used in various applications, including no-stick coatings and flame retardants in fire-fighting equipment. In the environment, PFAS are resistant to degradation and are considered "forever chemicals." In addition to their persistence, PFAS bioaccumulate and biomagnify in living organisms and harm human health. Concurrent with the production and release of PFAS in the environment, widespread global production and use of plastic have increased environmental contamination, mainly aquatic resources. Plastic breaks down, fragmenting into smaller particles to create microplastics, particles 5 mm to 1 μm in size. Microplastics enter the global food chain and impact the health and function of living organisms. When consumed by wildlife, microplastics accumulate in and obstruct the digestive tract, disrupt physiological processes, and transfer toxic contaminants that can accumulate within body tissues. Despite national and international pressures to curb environmental contamination of PFAS and microplastics, data regarding contamination and toxic effects are lacking, particularly in freshwater systems. As contaminants of emerging concern, research on PFAS and microplastics is critical to addressing data gaps to quantify and understand potential environmental impacts. One management strategy to assess and monitor environmental impacts is using indicator species that reflect the biotic or abiotic state of the environment.

Alligators are ubiquitous in freshwater and brackish wetlands throughout the southeastern United States. Because of their broad diet and long lifespan, these animals effectively indicate contamination by heavy metals, persistent organic pollutants, and other deleterious compounds within wetland ecosystems. As such, alligators are potentially valuable indicators of microplastic and PFAS pollution in wetlands. In addition, thousands of wild alligators are harvested annually in the southeastern United States during private and public land hunts. This harvest provides a unique opportunity to use established legal alligator harvest from the southeastern US to collect alligator stomach samples for analysis of diet and microplastics and tissue samples to explore regional trends in PFAS contamination. Our project proposes to 1) address alligator diet knowledge gaps for South Carolina and at a regional scale; 2) recover and characterize ingested microplastics in alligators; 3) test for PFAS in alligator muscle tissue (tail biopsy) to explore potential patterns in contamination; and 4) assess the suitability of alligators as indicators of microplastic and PFAS contamination in wetlands.

Watershed scale land-use practices and their relationship with wetland ecosystem health

Sindupa De Silva

Wetlands help improve the water quality of their watersheds. Wetlands are not comprehensively protected from watershed-scale anthropogenic land-use practices despite their benefits. Wetlands in West Virginia, USA, contain diverse freshwater wetlands that drain into two ecologically and economically vital watersheds: the Chesapeake Bay and the Gulf of Mexico. Therefore, wetlands in West Virginia play an essential role in helping improve the quality of water that enters the Chesapeake Bay and Gulf of Mexico. West Virginia’s landscape is also utilized for various anthropogenic land-use practices ranging from fossil fuel industries to federally protected national forests. We hypothesize that harmful watershed-scale anthropogenic land-use practices will negatively impact wetland ecosystem health and, consequently, their ability to improve water quality. Therefore, to improve our understanding of how watershed-scale land-use practices influence wetland ecosystem health, we assessed 200 wetlands across West Virginia and evaluated their water quality, vegetation composition, and aquatic macroinvertebrate diversity and abundance. We used GIS software to delineate the contributing watersheds of each wetland and extracted the total areas of different land cover/ land-use practices within each watershed. Using statistical analyses, we then evaluated the relationship between watershed-scale land-use practices and the indicators of wetland ecosystem health.

From preliminary analyses of our water quality data, we observed that as the different types and total areas of anthropogenic land-use practices increased above a wetland, the water quality of the wetland decreased. For example, as the area of high-intensity development increased - water quality variables such as conductivity, nitrogen, phosphorus, and E. Coli bacteria concentrations also increased. These results indicate that anthropogenic land-use practices influence wetland ecosystem health and could have cascading negative ecological impacts as water from these wetlands drains into the Chesapeake Bay and the Gulf of Mexico. In addition to evaluating ecosystem health, we will use these data to determine if anthropogenic land-use practices impact a wetland’s ability to perform select water quality functions. The results of this project will be used to develop wetland water quality standards for West Virginia and help advance more comprehensive wetland regulations.