Relationships between landscape structure and breeding birds in the Oregon Coast Range

• Published in: Ecological monographs Vol. 65; no. 3; pp. 235 - 260
• Main Authors: McGarigal, Kevin, McComb, William C.
• Format: Journal Article
• Language: English
• Published: Washington, DC The Ecological Society of America 01.08.1995; Ecological Society of America; Duke University Press
• Subjects: AGRONOMIC CHARACTERS; analysis of variance; Animal and plant ecology; ANIMAL SALVAJE; ANIMAL SAUVAGE; Animal, plant and microbial ecology; Aves; Aviculture; basins; BIODIVERSIDAD; BIODIVERSITE; BIODIVERSITY; Biological and medical sciences; BIOLOGICAL DIFFERENCES; BIRDS; BOSQUES; breeding; CARACTERE AGRONOMIQUE; CARACTERISTICAS AGRONOMICAS; coasts; Coniferous forests; DENSIDAD DE LA POBLACION; DENSITE DE POPULATION; DIFERENCIAS BIOLOGICAS; DIFFERENCE BIOLOGIQUE; ECOLOGIA; ECOLOGIE; ECOLOGY; Forest ecology; Forest fragmentation; Forest habitats; forest stands; FORESTS; FORET; FRAGMENTATION; Fundamental and applied biological sciences. Psychology; HABITAT FRAGMENTATION; Habitats; intensive forestry; interspecific variation; LANDSCAPE; Landscape ecology; Landscapes; OISEAU; OREGON; PAISAJE; PAJAROS; PAYSAGE; POPULATION DENSITY; SPECIES ABUNDANCE; SPECIES DIFFERENCES; SPECIES DIVERSITY; STAND STRUCTURE; Synecology; Terrestrial ecosystems; Troglodytidae; urban development; vegetation cover; WILD ANIMALS; wild birds; Wildlife habitats; Oregon; United States; North America; America; United States > US; USA, Oregon; Vertebrata; Forests; Landscape; Environment impact; Environmental factor; Habitat selection; Aves; Ecological abundance; Fragmentation
• ISSN: 0012-9615; 1557-7015
• DOI: 10.2307/2937059

Human-caused fragmentation of forests is increasing, yet the consequences of these landscape changes to vertebrate communities are poorly understood. Although bird community response to forest fragmentation caused by agricultural or urban development has been well studied, we have little understanding of these dynamics in landscapes undergoing intensive forest management, where late-seral forest stands are separated by younger forest stands of varying ages and are part of a spatially and temporally dynamic forest landscape. We investigated the relationship between landscape structure and breeding bird abundance in the central Oregon Coast Range. We sampled vegetation and birds in 30 landscapes (250-300 ha) distributed equally among three basins. Landscapes represented a range in structure based on the proportion of the landscape in a late-seral forest condition and the spatial configuration of that forest condition within the landscape. We computed a variety of landscape metrics from digital vegetation cover maps for each landscape. Using analysis of variance and regression procedures, we quantified the independent effects of habitat area and configuration on 15 bird species associated with late-seral forest. Species varied dramatically in the strength and nature of the relationship between abundance and several gradients in habitat area and configuration at the landscape scale. Landscape structure (composition and configuration) typically explained <50% of the variation in each species' abundance among the landscapes. Species' abundances were generally greater in the more heterogenous landscapes; that is, they were associated with the more fragmented distribution of habitat. Only Winter Wrens showed evidence of association with the least fragmented landscapes. These results must be interpreted within the scope and limitations of our study. In particular, the scale of our analysis was constrained by the lower and upper limits of resolution in our landscapes, as set by minimum patch size and landscape extent, respectively. Thus, our results do not preclude much stronger and different relationships at finer and/or coarser scales. In addition, our community-centered habitat classification scheme and artificially discrete representation of patch boundaries may not have captured the functionally meaningful heterogeneity for each species. Finally, our analysis was limited to relatively common and widespread diurnal breeding bird species. Species sensitive to habitat fragmentation at the scale of our analysis may have been rare already and therefore not subject to the parametrical statistical approach that we employed.