WETLANDS: UNIQUE AND ENDURING ECOLOGICAL COMMUNITIES

S.A. Wissinger. Biology Department, Allegheny College, Meadville, PA 16335

Wetlands are often portrayed as spatial and/or temporal ecotones between water and land. However, most wetlands are not adjacent to aquatic (>2m depth) ecosystems nor are they transitional stages in a hydrarch succession from aquatic to terrestrial habitat. Many dominant plants in wetlands are specialists with adaptations distinct from both aquatic and terrestrial species; i.e., they can not tolerate extended inundation or deep water, nor do they compete well in unsaturated, aerobic soils. Not surprisingly, the presence of hydrophytic vegetation has become one of the main criteria for delineating jurisdictional wetlands. Here I argue that many of the dominant animals in wetlands are also specialists that are similarly restricted to the physical (drying, freezing, subhabitats) and biological (unique plants, competitors, predators) conditions in wetlands. Differences in species composition between wetland and aquatic animal communities often reflect tradeoffs between the life history and physiological adaptations that allow for the exploitation of temporary waters, and vulnerability to top predators (e.g., fish) that require deep, permanent water. Effective strategies for conserving wetland biodiversity will require that ecologists, policy makers, and regulators conceptualize wetlands as distinct and enduring habitats with a distinctive flora and fauna rather than as ecotones or transient features of the landscape