title: Emulating natural disturbances for declining late-successional species: a case study of the consequences for cerulean warblers (Setophaga cerulea).
abstract: Forest cover in the eastern United States has increased over the past century and while some late-successional species have benefited from this process as expected, others have experienced population declines. These declines may be in part related to contemporary reductions in small-scale forest interior disturbances such as fire, windthrow, and treefalls. To mitigate the negative impacts of disturbance alteration and suppression on some late-successional species, strategies that emulate natural disturbance regimes are often advocated, but large-scale evaluations of these practices are rare. Here, we assessed the consequences of experimental disturbance (using partial timber harvest) on a severely declining late-successional species, the cerulean warbler (Setophaga cerulea), across the core of its breeding range in the Appalachian Mountains. We measured numerical (density), physiological (body condition), and demographic (age structure and reproduction) responses to three levels of disturbance and explored the potential impacts of disturbance on source-sink dynamics. Breeding densities of warblers increased one to four years after all canopy disturbances (vs. controls) and males occupying territories on treatment plots were in better condition than those on control plots. However, these beneficial effects of disturbance did not correspond to improvements in reproduction; nest success was lower on all treatment plots than on control plots in the southern region and marginally lower on light disturbance plots in the northern region. Our data suggest that only habitats in the southern region acted as sources, and interior disturbances in this region have the potential to create ecological traps at a local scale, but sources when viewed at broader scales. Thus, cerulean warblers would likely benefit from management that strikes a landscape-level balance between emulating natural disturbances in order to attract individuals into areas where current structure is inappropriate, and limiting anthropogenic disturbance in forests that already possess appropriate structural attributes in order to maintain maximum productivity.
authors: Department of Forestry, Wildlife, and Fisheries, University of Tennessee, Knoxville, TN, USA. tboves@illinois.edu
authors: Than J
authors: TJ
authors: Boves
authors: David A
authors: DA
authors: Buehler
authors: James
authors: J
authors: Sheehan
authors: Petra Bohall
authors: PB
authors: Wood
authors: Amanda D
authors: AD
authors: Rodewald
authors: Jeffrey L
authors: JL
authors: Larkin
authors: Patrick D
authors: PD
authors: Keyser
authors: Felicity L
authors: FL
authors: Newell
authors: Gregory A
authors: GA
authors: George
authors: Marja H
authors: MH
authors: Bakermans
authors: Andrea
authors: A
authors: Evans
authors: Tiffany A
authors: TA
authors: Beachy
authors: Molly E
authors: ME
authors: McDermott
authors: Kelly A
authors: KA
authors: Perkins
authors: Matthew
authors: M
authors: White
authors: T Bently
authors: TB
authors: Wigley
mesh_terms: D000818:Animals; D001061:Appalachian Region; D003247:Conservation of Natural Resources; D017753:Ecosystem; D005260:Female; D008297:Male; D008954:Models, Biological; D011156:Population Density; D011157:Population Dynamics; D012098:Reproduction; D020308:Songbirds / Q000033:anatomy & histology / Q000502:physiology*; D014197:Trees / Q000502:physiology*