Impacts of Human Disturbance on Microbial Spatial Patterns in Headwater Wetlands and Linkages to Manageable Wetland Traits

EPA Grant Number: F07E10814
Title: Impacts of Human Disturbance on Microbial Spatial Patterns in Headwater Wetlands and Linkages to Manageable Wetland Traits
Investigators: Moon, Jessica B.
Institution: Pennsylvania State University
EPA Project Officer: Michaud, Jayne
Project Period: January 1, 2007 through January 1, 2010
RFA: STAR Graduate Fellowships (2007) RFA Text |  Recipients Lists
Research Category: Aquatic Ecology and Ecosystems , Academic Fellowships , Fellowship - Aquatic Systems Ecology


Since the 18th century wetlands in the United States have been altered due to their position in a matrix of anthropogenic land changes. These alterations are of concern because through supporting services, such as microbial biochemical cycling, wetlands help to regulate climate and water quality. Given the importance of these ecological services, the goal of this research is to examine how human disturbance affects microbial biochemical cycling in wetlands. More specifically, the objectives of this project are to:

  1. Determine whether the spatial heterogeneity of soil parameters (e.g., microbial biomass, microbial composition, and microbial habitat) in natural wetlands is influenced by the level of human disturbance present,
  2. Scale up and evaluate patterns in soil microbial habitat parameters in natural wetlands that fall along Pennsylvania’s disturbance gradient, and
  3. Examine the patterns between soil parameters and wetland traits (e.g., vegetation parameters and microtopography) within individual wetlands and across the wetland disturbance gradient.


First, eight Pennsylvania headwater wetlands—four with low levels of human disturbance and four with high—will be used to characterize the spatial differences in soil parameters (i.e., microbial biomass, microbial composition, soil moisture, total carbon, extractable soil organic carbon, total nitrogen, nitrate, ammonium, and soil texture). These same sites will be used to collect wetland trait measurements. Geostatistics will be used to analyze how disturbance influences the spatial variability of soil parameters, and to examine the relationships between soil parameters and wetland traits. Finally, an existing data set of soil microbial habitat parameters (n ~ 10), collected from 222 Pennsylvania wetlands between 1993 and 2006 by the Penn State Cooperative Wetlands Center, will be used in classification and regression tree analysis to identify relationships between the sites’ disturbance scores and their soil microbial habitat parameters.

Expected Results:

This research will identify important wetland microbial spatial patterns that exist across a human disturbance gradient. These patterns may be used to predict net changes in the global carbon and nitrogen source/sink dynamics of wetland ecosystems. By relating these microbial spatial patterns to manageable wetland traits, this research will also assist management officials in their efforts to maintain the resilience of wetland ecosystems, and to restore functions to wetlands that have been disturbed.

Supplemental Keywords:

wetlands, soils, biochemical cycling, microbial biomass, microbial composition, microhabitat, disturbance, microtopography, vegetation, spatial heterogeneity, geostatistics,

Progress and Final Reports:

  • 2007
  • 2008
  • Final