A Comparison of Decomposition in Restored and Natural Nontidal Forested Wetlands in Eastern VirginiaEPA Grant Number: U915540
Title: A Comparison of Decomposition in Restored and Natural Nontidal Forested Wetlands in Eastern Virginia
Investigators: Schmidt, John M.
Institution: Virginia Polytechnic Institute and State University
EPA Project Officer: Packard, Benjamin H
Project Period: August 1, 1999 through August 1, 2001
Project Amount: $54,020
RFA: STAR Graduate Fellowships (1999) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Aquatic Ecosystems , Fellowship - Aquatic Ecology and Ecosystems
The objective of this research project is to compare the rates and organisms that mediate decomposition in restored and natural forested wetlands along a moisture and time gradient.
This project studies constructed and natural ?reference? wetlands, focusing on two main parts: a water budget and a decomposition study. The wetlands the investigator is studying were created by the Virginia Department of Transportation to replace wetlands destroyed by highway construction. A 10-year-old and a 2-year-old wetland are being studied. The water budget will model the hydrology of the 10-year-old wetland by estimating the losses and gains from the system. Evapotranspiration, groundwater flow, surface water flow, and precipitation will be measured or estimated to complete the budget. Decomposition rates will be estimated through both cloth burial strip and litterbag methods. The cloth strip method relates the decreasing tensile strength of a strip of unbleached cotton fabric to the rate of cellulose decomposition.
Litterbags have been used extensively to study decomposition in both terrestrial and aquatic environments. Typically, a large number of mesh bags are filled with plant litter, placed in an area, and then a few bags are periodically removed to determine weight loss and mineral composition. For this study, two different types of litter will be used; the hardwood leaves common in the reference areas and the emergent marsh vegetation. To estimate the proportion of decomposition losses from different sources, two mesh sizes will be used. A fine mesh will estimate microbial and leaching losses by excluding invertebrates, and a coarse mesh (2-4 mm) will allow access to all but the largest macroinvertebrates. The arthropod and invertebrate communities will be surveyed to determine which organisms are responsible for the litter breakdown. The main comparison will be between the rates and sources of decomposition between restored and natural wetlands. Secondary comparisons will examine decomposition along a temporal and moisture gradient in the created wetlands. This study is especially attractive because the decomposition and hydrology can be correlated with the water quality, redox conditions, and soil development studies conducted by previous researchers. Site selection for litterbag placement was conducted to optimize the opportunity for these correlations and connections to be made. Decomposition is expected to vary by wetland type (restored or natural), moisture, age since restoration, and litter type.
Decomposition is expected to vary by wetland type (restored or natural), moisture, age since restoration, and litter type.