Avian-habitat relationships in urban and suburban tidal marshes of Connecticut

by Kristin Schaumburg¹, William M. Giuliano², and Gail A. Langellotto³

¹ Louis Calder Center—Biological Field Station, Department of Biological Sciences, Fordham University, 53 Whippoorwill Road, Armonk, NY 10504

² Department of Wildlife Ecology and Conservation, University of Florida, PO Box 110430, Gainesville, FL 32611

³ Department of Horticulture, Oregon State University, 4017 Ag and Life Sciences Building. Corvallis, OR 97331

Abstract

Tidal marshes support an array of avian species and provide essential habitat for tidal marsh specialists. Recent population declines of marsh specialists are largely attributed to habitat change, particularly in urban and suburban landscapes. The rapid geographic expansion of invasive common reed (Phragmites australis) throughout tidal marshes is of particular concern. Habitat structural changes of tidal marshes associated with the spread and dominance of common reed will likely have direct and indirect impacts on avian use of such sites. Our objective was to determine the relationship between habitat characteristics and avian abundance and species richness within urban and suburban Connecticut tidal marshes, with a focus on the effect of common reed on avian communities, particularly tidal marsh specialists. We collected data via point counts and vegetation and macroinvertebrate sampling from 39 tidal marshes in Connecticut, from 2004 to 2005. Relatively high use by avian tidal marsh specialists and dominance of habitat classes indicative of "native" marshes suggest that study marshes have retained some habitat for marsh birds and at least some of the function of unaltered tidal marshes. Similarly, use by at least 8 species of conservation concern suggests that these marshes serve as important habitats for many at-risk species. Avian abundance, including that of tidal marsh specialists, differed among habitat classes, with habitats dominated by native species often supporting greater numbers of birds than common reed habitats. Site-level avian-habitat relationships provided further support for the value to marsh birds of habitats that maintain native conditions. To prevent further declines of many of avian species at the local site level, marshes must be protected from habitat loss and alteration.

Keywords: avian, habitat, macroinvertebrate, marsh, Phragmites australis, suburban, tidal, urban