Date of Award

Spring 5-4-2015

Document Type

Honors Project

Degree Name

Bachelor of Science

Department

Earth and Environmental Sciences

First Advisor

Bass, Michael

Second Advisor

Whipkey, Charles

Major or Concentration

Environmental Science (Natural Science Concentration)

Abstract

According to USEPA's "No Net Loss," memorandum, wetlands must be created in compensation for any unavoidable impacts resulting from development. Ideally, each individual constructed wetland should become functionally comparable to its natural predecessor. Three constructed non-tidal palustrine forested wetlands (PFO) and one natural PFO were compared based on vegetative proliferation and soil physiochemical characteristics in the Virginia Piedmont and Coastal Plain provinces. Vegetation parameters included woody stem counts, a list of total wetland flora, Basal Area (BA), and Diameter at Breast Height (DBH) measurements. Soils were flooded using synthetic-enriched freshwater (with naturally occurring concentrations of NH4-N and PO4-P) for 72 hours and measured for N exchange/release and P sorption/desorption, in order to approximate biogeochemical nutrient cycling as a result of prolonged inundation. All wetland soils released N (2.65-13.6 mg NH4-N/m2). P sorption/desorption ranged from -4.35 mg PO4-P/m2 (desorption) to 16.6 mg PO4-P/m2 (sorption). The natural wetland (PNWL) supported significantly larger trees (DBH=13.1±9.86 cm) (BA=9.93 cm2 ha-1) (p<0.0001) than constructed sites, the lowest density of woody stems (1102 ws ha-1), the lowest species richness (SR=14), while also containing the most phosphorus and percent OM through a depth of 30 cm. Overall, the 19 year old SMWL (Spotsylvania Mitigated Wetland) differed significantly from PNWL with a higher density of predominantly small trees (4095 ws ha-1) (p=0.046) (DBH=0.99±0.96 cm) and sandy entisols which show a drastic reduction in soil quality with depth.

Download

Share

COinS