Hydric soils across Pennsylvania reference, disturbed, and mitigated wetlands

Soils were compared among natural HGM wetland types, contrasting reference standard wetlands to disturbed wetlands of that type. These latter sites were disturbed to some extent, from stressors occurring on site, within the buffer, and/or from the surrounding landscape. As expected the soils affected by glaciation in the northeastern and northwestern corners of Pennsylvania were wetter than soils from other ecoregions, and the number and density of wetlands was higher. Soil texture was coarser where hydraulic energies were greater, such as in riverine wetlands. Disturbed wetlands tended to have finer textured soils composed of more silt and clay, suggesting that they receive inputs of eroded sediments from the surrounding landscapes. Organic matter was higher in some HGM types, such as fringing and riparian depressions where soils are more saturated or inundated. Soils data from Riparia's set of reference wetlands is available through a searchable web interface at their website. A review of the literature comparing reference wetlands to mitigation projects continues to indicate the latter are not reaching the functional performance of natural wetlands.