Plant community composition as a function of geochemistry and hydrology in three appalachian wetlands

Appalachian mountain wetlands are uncommon and diverse ecosystems; however, they are often susceptible to extensive alteration or destruction due to coal mining, highway construction, and quarrying. This study aimed to determine vegetation composition at three pristine wetlands and establish relationships with previously reported hydrologic, edaphic, and porewater characteristics to provide baseline data that could enhance wetland mitigation or restoration projects. Herbaceous vegetation was assessed by visually estimating percent cover for bryophyte and vascular species and by determining stem density for vascular taxa using 1 m ² quadrats located along transects. Multiple response permutation procedures (MRPPs) based upon importance values confirmed that species composition differed significantly (P < 0·001) among the sites. Nonmetric multi-dimensional scaling (NMDS) indicated that soil moisture conditions during the fall, soil chemistry, and porewater chemical composition influenced plant community composition. The first wetland (Martins Fork) was primarily dominated by Osmunda cinnamomea, Osmunda regalis, and Sphagnum palustre in response to drier soil during the fall season, higher soil pH, and weakly minerotrophic soil and porewater. The second wetland (Kentenia) was overwhelmingly dominated by S. palustre due to lower soil pH and persistently high water levels. Vegetation at the third wetland (Four Level) was distinguished by strongly dominant Scirpus polyphyllus and Glyceria striata and responded to higher soil and porewater Ca, Mg, and P concentrations as well as a light intensity gradient. The diverse vegetation and physico-chemical characteristics indicate that these sites, although small in size, support regional biodiversity and are potential reference wetlands.