PARENT SESSION
Oral Session #30: Landscape Ecology: Dynamics and patterns. Presiding: A. Hansen.
Tuesday, August 7, 2001. 1:00 PM to 5:00 PM. Madison Ballroom D.
Landscape relationships of waterbird colonies on the Virginia Coast Reserve.
Porter, John1, Erwin, R. Michael1,2, Truitt, Barry3, 1 2 3
ABSTRACT- A 23-year database of waterbird colonies was analyzed to test for relationships between landscape composition and colony location. For each species (Black Skimmer [Rynchops niger], Common Tern [Sterna hirundo], Least Tern [S. antillarum], Gull-billed Tern [S. nilotica] and Herring Gull [Larus argentatus]), satellite-derived land cover within distances of 200, 500, 1000 and 5000 meters from reported colony locations was tallied and compared to an equal number of random locations within the surveyed area using a two-way multivariate analysis of variance (MANOVA) with year (1976, 1981, 1986, 1991, 1996) and location type (real colony vs random) as factors. Results showed that landscape composition could effectively distinguish between colony and random locations for all species (p ≤ 0.001), primarily based on landscape composition within 1 km of the locations. Only one species (Common Tern) showed any indication of temporal shifts in landscape utilization (p ≤ 0.05). For no species was there a significant year by location type interaction, indicating that the differences between colony and random locations remained stable over time. Classification using discriminant analysis indicates that we can distinguish between colony and random locations more than 70% of the time based on landscape composition alone.
KEY WORDS: Colonial Waterbird, Landscape Composition, Island, Land Cover