Importance of patch scale vs landscape scale on selected forest birds

Authors

  • Michelle Lee,

  • Lenore Fahrig,

  • Kathryn Freemark,

  • David J. Currie


M. Lee and L. Fahrig (correspondence), Ottawa-Carleton Inst. of Biology, Carleton Univ., 1125 Colonel By Drive, Ottawa, ON, Canada K1S 5B6 (lfahrig@ccs.carleton.ca). – K. Freemark, Canadian Wildlife Service, Environment Canada, 100 Gamelin Blvd, Hull, QC, Canada K1A 0H3. – D. J. Currie, Ottawa-Carleton Inst. of Biology, Univ. of Ottawa, Box 450, Station A, Ottawa, ON, Canada K1N 6N5.

Abstract

The management and protection of natural areas have primarily occurred in isolation from surrounding land management. The structure of surrounding land cover, however, may be important to the abundance and reproductive success of birds within a habitat patch. We investigated the relative importance of forest patch area, within patch habitat and surrounding landscape forest cover on the abundance of three Neotropical migrant bird species thought to be area-sensitive (ovenbird [Seiurus aurocapillus], wood thrush [Hylocichla mustelina] and red-eyed vireo [Vireo olivaceus]), and on pairing success of the ovenbird. We selected 31 isolated forest patches of differing sizes, and three 80-ha plots in continuous forest each centered within non-overlapping 200-ha landscapes, such that patch area and landscape forest cover were uncorrelated among landscapes. Each study plot was surveyed to estimate abundances of territorial males and ovenbird pairing success. Landscape forest cover (p<0.05) explained the most variation in ovenbird abundance, while percent deciduous forest cover within patches (p<0.05) and patch size (p<0.05) explained the most variation in red-eyed vireo and wood thrush abundance, respectively. Patch size was a significant (p<0.05) predictor of abundance for all three study species; however, density for all species decreased significantly (p<0.05) with patch size. Ovenbird pairing success was higher in continuous forest plots than in forest patches (p=0.018). This study's findings suggest that the relative importance of within patch characteristics, patch size and landscape forest cover varies for different bird species, and that conservation efforts would benefit from the inclusion of all three factors.

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