Hydric Soil Field Indicators For Use in Mid-Atlantic Barrier Island Landscapes.

Hydric soils in Holocene-aged barrier island landscapes lack morphologies typically associated with saturated and reducing conditions, making identification and delineation of wetlands problematic. Our objective was to develop field indicators that could be used to effectively recognize hydric soils in these environments. Ten topographic transects were established at Assateague Island National Seashore, MD, USA. Transects spanned a gradient of drainage classes from dune crests to interdunal swales. Water tables and reducing conditions were monitored to determine hydric status. Soil descriptions along each transect were used to identify morphological features indicative of hydric conditions. Most hydric soils at these sites did not meet any currently recognized field indicators. Soil development was limited to organic matter accumulation (Oa and/or A horizons), which was greatest in hydric soils. Hydric soils were best identified by the presence of chroma colors less than 2 in mineral soils, or having at least 1 cm of muck (Oa horizon) with a chroma of 1 or 2. Based on these characteristics, we propose a revision to hydric soil field indicator A9 (1.0 cm muck) and a new indicator, both restricted for use in Holocene-aged barrier island landscapes. These indicators will allow for identification of hydric soils and improve the accuracy and ease of delineation of wetlands in these environments.