Relative abundance of forest songbirds on Cherokee National Forest and the surrounding southern Appalachian region based on analysis of North American breeding bird survey and US Forest Service point-count data
Date of Award
Master of Science
Wildlife and Fisheries Science
Joseph D. Clark, Patrick Keyser
Managed forests provide dynamic habitats that support a diversity of bird species. The Cherokee National Forest (CNF) in eastern Tennessee provides a good case study on how forest management can affect forest bird communities. Also, given that the CNF has a wide elevation gradient; it can serve as a case study for potential climate change effects on elevationally-dependent species.This thesis used a large point-count database collected on the CNF, North American Breeding Bird Survey count data, and data on various forest management and climate variables to assess how avian populations have changed over the 1992-2015 period. Using Poisson regression, I analyzed the changes in relative abundance for 18 focal songbird species that occupy a variety of forest types and age classes across an elevation gradient on the forest. I modeled each species’ relative abundance with timber harvest and prescribed burning covariates to identify significant relationships. I also modeled relative abundance with climate covariates to understand if there was a climate link to changes in relative abundance on the CNF and surrounding areas.Twelve of 18 focal species on the CNF and 3 of 18 species on adjacent BBS routes had significant change (7 decline, 5 increase- CNF; 3 decline- BBS) in abundance over the 24-year period. Six of 18 species abundance trends differed depending on if the BBS route was on public land vs. private land. Four of 18 species showed positive relationships with the amount of timber harvested on the CNF and 2 of 18 species showed negative relationships with prescribed burning. Four species along BBS routes showed positive relationships with timber harvest whereas 2 species showed negative relationships. Eight of 18 focal species shifted elevation on the CNF during the study period, with 2 species moving upslope and 6 species moving downslope. Most species abundances were related to a complex interaction of temperature and precipitation covariates. In conclusion, relative abundance for many species is changing over space and time on the CNF and on adjacent BBS routes on public and private lands. Forest management and climate covariates are related to those changes for many species.
Isenhower, Andrew Travis, "Relative abundance of forest songbirds on Cherokee National Forest and the surrounding southern Appalachian region based on analysis of North American breeding bird survey and US Forest Service point-count data. " Master's Thesis, University of Tennessee, 2017.