RELATIONSHIP BETWEEN HABITAT AREA AND THE DISTRIBUTION OF TIDAL MARSH BIRDS

• Published in: The Wilson bulletin (Wilson Ornithological Society) Vol. 114; no. 3; pp. 314 - 323
• Main Authors: BENOIT, LORI K, ASKINS, ROBERT A
• Format: Journal Article
• Language: English
• Published: Lawrence, KS Wilson Ornithological Society 01.09.2002
• Subjects: Ammodramus; Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; Bird nesting; Bird populations; Birds; Brackish water ecosystems; Cistothorus palustris; CONTENTS; Environmental aspects; Evaluation; Forest habitats; Fundamental and applied biological sciences. Psychology; grasses; Habitat fragmentation; habitats; highlands; Marsh ecology; Marshes; Meadows; regression analysis; Salt marshes; Sparrows; surveys; Synecology; Vegetation; Waterfowl; Wildlife habitats; Virginia; Connecticut; United States; North America; America; Brackish water environment; Habitat suitability; Population decline; Fragmentation; Salt marsh; Logistic regression; Vertebrata; Faunal survey; Animal community; Population dynamics; Cistothorus palustris; Habitat; Aves; Ecological abundance
• ISSN: 0043-5643; 2162-5204
• DOI: 10.1676/0043-5643(2002)114[0314:RBHAAT]2.0.CO;2

To assess the relationship between marsh area and relative abundance of tidal marsh bird species, we surveyed birds on 86 circular plots in 40 salt and brackish tidal marshes in Connecticut. We measured marsh area in two ways: the amount of contiguous marsh vegetation not interrupted by broad barriers (>500 m of open water or >50 m of upland habitat) and by narrow barriers (>30 m of open water or >10 m upland). We determined the relationship between marsh area and the relative abundance of particular species (mean number of individuals per survey plot) with linear or logistic regression. When the broad barrier definition was used, we found that all three species of short grass meadow specialists, Willets (Catoptrophorus semipalmatus), Seaside Sparrows (Ammodramus maritimus), and Saltmarsh Sharp-tailed Sparrows (A. caudacutus), were less abundant or absent in survey plots in smaller marshes. The Seaside Sparrow and Willet also showed a significant tendency to be less frequent in smaller marshes when the narrow barrier definition was used. In contrast, species that used a wider range of wetland types, as in the Virginia Rail (Rallus limicola), Marsh Wren (Cistothorus palustris), and Swamp Sparrow (Melospiza georgiana), were equally frequent on plots in marshes of different areas. Our results are consistent with the hypothesis that fragmentation of marsh systems with artificial habitat causes a decline in the density of short grass meadow specialists in the remaining patches of appropriate habitat.