PARENT SESSION
Poster Session #37: Invertebrate Ecology.
Thursday, August 9, 2001. Presentation from 10:30 AM to 12:00 PM. Exhibition Hall
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Scales of coexistence for terrestrial gastropods within wooded wetlands.
Barthel, Matthew1, Nekola, Jeffrey1, 1
ABSTRACT- Richness patterns and diversity gradients for terrestrial gastropod communities are typically studied at relatively large (>100 m2) sample scales. Accumulating evidence suggests that terrestrial gastropod assemblages may also be organized at small extents (<1 m2 - 100 m2). To document scales of coexistence, terrestrial gastropod presence/absence data from microhabitats within three wooded wetlands of eastern Wisconsin were observed using a nested quadrat design of varying grain (0.01 m2, 1 m2) and extent (1 m, 20 m, 400 km ). Up to 15 or more taxa can co-occur within single 0.01 m2 microhabitats, while 21 or more can occur in surrounding 1 m2 areas. Up to 30 taxa were found in individual 400 m2 sites, and 53 taxa occur in this habitat type throughout eastern Wisconsin and Michigan's upper peninsula. This evidence suggests that alpha-diversity occurs at very small (ca. 10 cm) extents and accounts for up to 30% of regional diversity. Beta-diversity exists within sites at 1-20 m extents and accounts for up to 30% of regional diversity. Gamma-diversity accounts for approximately 40% of regional diversity. Based on these small-scale coexistence of such a large portion of the regional fauna it appear likely that some land snail species share similar niches.
KEY WORDS: terrestrial gastropods, species richness, diversity patterns, wooded wetlands