Project Results

Hemlock decline was unrelated to foraging habitat selection and apparent adult survival, but was related to nest site selection through an interaction with percent ground cover of exposed live tree roots: birds selected for nest sites in areas with more exposed live roots but only when hemlock was in poor condition. Nest survival was lower in areas where deciduous species (vs. evergreen species) dominated the understory, suggesting that adelgid invasion could indirectly impact waterthrush fitness depending on how vegetative succession proceeds following hemlock decline.

About This Project

An invasive insect, the Hemlock Woolly Adelgid (HWA), is causing Eastern Hemlock tree decline in the Appalachian Mountains. The Louisiana Waterthrush (LOWA) is a bird that may indicate the degree to which HWA threatens riparian ecosystems with declining hemlock. By studying LOWA habitat use and reproductive success, I aim to determine how hemlock decline affects the birds and riparian ecosystem condition. Such knowledge is important for conserving the rich biodiversity of the Appalachians.

Ask the Scientists

What is the context of this research?

Once infested, hemlocks can die within 5 years. Current research has investigated consequences of HWA infestation and treatment strategies. Few studies have taken advantage of this natural experiment (chemically treated vs. untreated areas) to explore if/how a bioindicator (i.e., a species that represents ecosystem condition) like LOWA, presumed to be adapted to one forest type and associated abiotic conditions, may respond to shifts in forest structure and composition. Mapping LOWA territories, monitoring nests and provisioning, and surveying vegetation and hemlock health will uncover potential impacts of hemlock decline on LOWA and implications for riparian ecosystem condition. Increasing our understanding of HWA infestation will help park officials manage for sustaining biodiversity.

What is the significance of this project?

Riparian ecosystems are some of earth's most diverse and threatened. My research seeks to inform best management practices to conserve riparian ecosystem condition.

Great Smoky Mountains National Park in eastern Tennessee, USA, boasts over 3200 km of riparian habitat and is the nation's most visited park. It has environmental, economical, and cultural importance as a source of national pride. Conserving the Smokies is necessary for educating and inspiring future scientists. As part of my project, I will work with Great Smoky Mountains Institute at Tremont to educate citizens about HWA infestation, LOWA as bioindicators, and actions citizens can take to conserve riparian areas. Involving citizens in data collection is essential to creating lasting connections with nature.

What are the goals of the project?

My goal is to determine breeding LOWAs’ relationship(s) to hemlock decline by studying habitat use/selection, reproductive success/fitness, and provisioning. Study sites include chemically treated and untreated hemlocks. After conducting vegetation and hemlock health surveys, I will analyze LOWA breeding data with habitat characteristics and hemlock condition. I will report my results to the national park to provide hemlock health information in unmonitored areas. Research began in 2015 and will continue in 2016.

My project also utilizes LOWA as a tool for citizen science education. By involving volunteers in data collection and leading field based classes for children, I will engage the public with my project and teach the importance of conservation efforts to ecosystem condition.