Linking landscape properties to local hydrogeologic gradients and plant species occurrence in minerotrophic fens of New York State, USA: A hydrogeologic setting (HGS) framework

Abstract

We present a Hydrogeologic Setting (HGS) framework and the results of subsequent field evaluation for minerotrophic fens throughout New York State, USA. HGS uses a hierarchical approach to link landscape properties to local environmental gradient and, therefore, the plant communities that are associated with calcareous wetlands. This framework was organized into three general classes (i.e., chemical, physical, and spatial), which cumulatively represent the primary top-down factors driving fen occurrence. For 45 fen sites in the New York Natural Heritage Program (NYNHP) database, landscape setting was inferred based on review of published materials (e.g., geologic, topographic, soils maps, and reports). To examine the relationship between HGS and local environmental gradients, nested observation well clusters were placed in 30 of the fen sites. Environmental gradients were quantified in the field (e.g., water depth, pore water pH, temperature, and specific conductivity) and laboratory (e.g., dominant ion and major limiting nutrients concentrations). Statistical analyses were used to relate HGS to local environmental gradients, ecological community, and fen indicator species occurrence. Results suggest that known New York fens occupy distinct hydrogeologic settings, that HGS is significantly correlated to local environmental gradients, and that HGS and local environmental gradients are significantly related to fen ecological community and indicator species occurrence. We used this HGS framework for fens, but the rationale provided may be applied more broadly or narrowly to a range of ecosystem types. © 2002, The Society of Wetland Scientists.