Evaluating the Impact of Eastern Hemlock Decline on Louisiana Waterthrush Demographics and Behavior in Great Smoky Mountains National Park

摘要

Eastern hemlock (Tsuga canadensis) is declining throughout the eastern United States due to the invasive hemlock woolly adelgid ( Adelges tsugae Annand). In the southern Appalachians, hemlock is concentrated in moist ravines and its loss threatens riparian specialists and habitat quality. The Louisiana waterthrush (Parkesia motacilla ) is an obligate-riparian species that could be sensitive to hemlock condition in the southern Appalachians, but how hemlock decline might impact it is currently unknown. I addressed this knowledge gap by evaluating relationships between hemlock decline and waterthrushes. First, I evaluated the ultimate effects hemlock decline could have on waterthrushes, focusing on survival and habitat selection. Second, I explored the proximate effects hemlock decline could have on waterthrushes via altered habitat quality, focusing on territory length and nestling provisioning and body condition. Short-term effects on waterthrush appear minimal, but long-term changes to riparian forest structure could have negative consequences for this species in the future.