Submitted to: Wetlands
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/1999
Publication Date: N/A
Interpretive Summary: Forested wetlands are the most common type of wetlands in the United States. They have many documented benefits for humanity. They filter water and, thus, improve water quality. Since they temporarily store water, they help reduce downstream flooding, and they obviously provide habitat for plants and animals. As renewable resources, they provide timber for American lumber markets. When harvest occurs, a goal of stakeholders is to provide restoration of wetland forest as quickly as possible so that benefits may resume. In this study, a disturbance index was developed to provide a restoration success measurement following timber harvesting by clear-cutting. This index allows forest and wetland managers to evaluate human impacts and evaluate speed of restoration success.
Technical Abstract: This study examined the usefulness of soil organic matter (SOM), total organic carbon (TOC), total Kjeldahl nitrogen (TKN), and total phosphorus (TP) as indicators of resilience in forested wetlands located within southeast Virginia, USA. Soil total phosphorus was significantly different among successional stages (p < 0.05). Although there were no significant differences in SOM, TOC, and TKN levels before and after timber harvest or between early and mature successional stages, there were consistent trends that may prove beneficial in determining reference standards. A Soil Perturbation Index was developed by combining the four soil parameters to determine extent of deviation from the biogeochemical reference (mature sites). This model indicated that biogeochemical functions decrease after harvesting, with the lowest point at 8 to 9 years after human alteration. This index predicts that it would take 16-17 years for SOM, TOC, TKN, and TP to return to pre-harvest conditions. Perturbation indices may be used for assessment of human impacts, restoration projects, and mitigation of wetlands. We maintain that a Soil Perturbation Index can be one useful component of an index of biotic integrity for wetland ecosystems.