NSF Award
2430196
Stream animals, in particular, require well-oxygenated environments to survive and reproduce, as they are accustomed to fast moving water. Environmental changes, such as increased temperature, flooding, and sediment pollution, can interact with bacterial activity to decrease dissolved oxygen in streams and thus, threaten stream biodiversity. The steam systems of the Appalachian U.S., appear to be suffering from these effects. This project will deploy high-frequency sensors across a forest cover gradient along Appalachian stream systems to test the overarching hypothesis that accelerating climate and land use change create low oxygen ‘hotspots’ on stream bottoms that cause local extinctions. Eastern hellbenders are a giant salamander species native to Appalachia and are highly sensitive to low oxygen. Using hellbenders as a model, the study will test whether low oxygen in stream habitats causes fathers to eat their young (filial cannibalism) at frequencies leading to population declines. Coupling sensors with new underwater video technology in innovative artificial nesting habitats, the study will link bacterial activity and oxygen to individual hellbender behaviors, cannibalism, and nesting success. Moreover, these findings will guide conservation actions, including releasing thousands of hatchlings (“head-starting”) to circumvent the population declines caused by filial cannibalism, thus preventing local extinctions, preserving genetic diversity of the species, and informing future actions to conserve declining stream biodiversity, including fishes, macroinvertebrates, and amphibians. The project will also build on a strong tradition of reaching underserved Appalachian communities through educational events, strategic engagement with community members, and recruitment of undergrads from Appalachia (often first-generation students) to serve on the integrated research and conservation action team.<br/><br/>Deoxygenation of aquatic habitats is a recognized threat of climate change, but past work has largely focused on coastal ecosystems and lakes/reservoirs, leaving its effect on stream ecosystems as a significant knowledge gap. Recent advances in high-frequency sensor technology enable real-time quantification of dissolved oxygen (DO) dynamics in surface waters. However, DO measurements are rarely made in benthic stream microhabitats utilized by sensitive taxa that likely have distinct chemical environments from surface waters. Linking DO and biogeochemistry in benthic microhabitats with hellbender behavior and reproductive outcomes will transform scientific understanding of often siloed research themes – organismal, population, and ecosystem ecology – and reveal a heretofore unrecognized impact of climate change on freshwater biodiversity. The study will also be the first in any species to mechanistically connect anthropogenic change, microhabitat DO, and parental behaviors that ultimately affect population dynamics. In doing so, the work will solve a 50 yr conservation mystery. Unlike past efforts such as captive breeding and head-starting of 2–4-year-old hellbenders, data will be used to inform evidence-based actions by a Conservation Agency to rear and release hatchlings to circumvent the bottleneck at the nest caused by filial cannibalism. This action is relatively low-cost and low-risk and its efficacy will be assessed using manual surveys, infrared video surveillance, and new genomics tools. In addition to informing hellbender and other stream taxa conservation, this research will train first generation undergraduate researchers, graduate students, and postdoctoral fellows in collaborative team science, conservation biology, biogeochemistry, and science communication with the general public.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
