2000 Progress Report: Assessment of forest disturbance in the mid-Atlantic region: a multi-scale linkage between terrestrial and aquatic ecosystems

EPA Grant Number: R826110
Title: Assessment of forest disturbance in the mid-Atlantic region: a multi-scale linkage between terrestrial and aquatic ecosystems
Investigators: Eshleman, Keith N. , Currie, William S. , Galloway, James N. , Gardner, Robert H. , Herlihy, Alan T. , Pitelka, Louis F. , Seagle, Steven W. , Townsend, Philip A. , Webb, James R.
Current Investigators: Eshleman, Keith N. , Galloway, James N. , Gardner, Robert H. , Pitelka, Louis F. , Seagle, Steven W. , Webb, James R.
Institution: University of Maryland , Oregon State University
Current Institution: University of Maryland , Oregon State University , University of Virginia
EPA Project Officer: Hahn, Intaek
Project Period: October 1, 1997 through September 30, 2002
Project Period Covered by this Report: October 1, 1999 through September 30, 2000
Project Amount: $697,834
RFA: Approaches to Multi-scale Ecological Assessment in the Middle Atlantic Region (1997) RFA Text |  Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Ecosystems


The objective of this project is to develop, test, validate, and demonstrate an analytical framework for assessing regional-scale forest disturbance in the mid-Atlantic region by establishing a multi-scale linkage between forest disturbance and forest nitrogen export to surface waters. It is hypothesized that excessive nitrogen (N) leakage (export) from forested watersheds is a potentially useful, integrative "indicator" of a negative change in forest function which occurs in synchrony with changes in forest structure and species composition. Our research focuses on forest disturbance associated with historical defoliation by the gypsy moth larva at spatial scales ranging from small watersheds to the entire region. The technical approach for establishing a multi-scale linkage between forest disturbance (i.e., gypsy moth defoliation) and N leakage to surface waters has made use of extensive forest, forest disturbance, and water quality data collected for the mid-Atlantic region at all spatial scales (intensive watershed sites, subregional survey, regional survey, and remotely-sensed data). These data were supplemented with on-the-ground measurements of forest species composition for a selected sample of watersheds for which N export had been previously monitored.

Progress Summary:

In early 2000, we completed an analysis of regional-scale forest disturbance and associated dissolved N export from Shenandoah National Park (SNP), Virginia?a large contiguous area of forested land within the Chesapeake Bay watershed. Long-term watershed research conducted in SNP indicates that annual export of dissolved N from forested watersheds to surface waters increases dramatically in response to vegetation disturbances. Our results suggest that a parsimonious, empirical, unit N export response function (UNERF) model can explain large percentages of the temporal variation in annual N export from a group of small gaged forested watersheds in the years following disturbance. The empirical UNERF modeling approach is completely analogous to the unit hydrograph technique for describing storm runoff, with the model representing annual N export as a linear deterministic process both in space and in time. The purposes of this analysis were to: (1) test the applicability of the UNERF model using quarterly streamwater nitrate data from a group of ungaged watersheds in SNP; (2) demonstrate a park-wide application of a regional UNERF model that references the geographic distributions of bedrock geology and the timing of gypsy moth defoliation over the entire SNP area; and (3) visualize the temporal and spatial patterns in vegetation disturbance and annual dissolved N export through the use of PC-based animation software. The results of our analysis showed that:
  • Forested ecosystems within SNP normally retain a very high percentage of atmospherically-deposited N, but forest disturbances such as insect defoliation can dramatically alter the input/output balance.

  • Annual nitrogen export from SNP forests began increasing in 1987 from a baseline rate of about 0.1 kg/ha, peaked in 1992 at an average rate of 1.68 kg/ha (more than a 1500 percent increase), and has been steadily declining since then.

  • Natural biogeochemical processes need to be considered in modeling N export dynamics of forests.

  • Linear systems models can apparently provide parsimonious approximations of ecosystem complexity that are useful for purposes of regionalization.

Future Activities:

In the final year of the research project, we will extend this type of integrative analysis to other forested watersheds in the Chesapeake Bay watershed. Our focus will be on first through third order drainages in the Mid-Atlantic Highlands Area (MAHA) that comprise a target subpopulation of the Environmental Monitoring and Assessment Program (EMAP) surface waters survey in the eastern United States. In completing this analysis, we will make use of historical remote-sensing data (e.g., AVHRR) as a means of better characterizing the spatial and temporal variations in forest defoliation within the region during the last 15 years.

Journal Articles on this Report : 3 Displayed | Download in RIS Format

Other project views: All 24 publications 9 publications in selected types All 8 journal articles
Type Citation Project Document Sources
Journal Article Eshleman KN, Gardner RH, Seagle SW, Castro NM, Fiscus DA, Webb JR, Galloway JN, Deviney FA, Herlihy AT. Effects of disturbance on nitrogen export from forested lands of the Chesapeake Bay watershed. Environmental Monitoring and Assessment 2000;63(1):187-197. R826110 (1999)
R826110 (2000)
R826110 (Final)
  • Abstract: Springer-Abstract
  • Other: Ingenta-Abstract
  • Journal Article Eshleman KN. A linear model of the effects of disturbance on dissolved nitrogen leakage from forested watersheds. Water Resources Research 2000;36(11):3325-3335. R826110 (1999)
    R826110 (2000)
    R826110 (Final)
  • Abstract: Wiley-Abstract
  • Journal Article Eshleman KN, Fiscus DA, Castro NM, Webb JR, Herlihy AT. Regionalization of disturbance-induced nitrogen leakage from mid-Appalachian forests using a linear systems model. Hydrological Processes 2004;18(14):2713-2725. R826110 (1999)
    R826110 (2000)
    R826110 (2001)
    R826110 (Final)
  • Abstract: Wiley-Abstract
  • Other: Harvard-Abstract
  • Supplemental Keywords:

    watersheds, regionalization, scaling, EMAP, modeling, remote sensing, mid-Atlantic region., RFA, Scientific Discipline, Ecosystem Protection, Environmental Exposure & Risk, Water, Geographic Area, Ecosystem Protection/Environmental Exposure & Risk, Water & Watershed, Nutrients, Hydrology, Environmental Chemistry, Ecosystem/Assessment/Indicators, exploratory research environmental biology, Ecological Effects - Environmental Exposure & Risk, Aquatic, Ecological Risk Assessment, Ecology and Ecosystems, Mid-Atlantic, Watersheds, Ecological Indicators, Scaling, nutrient transport, environmental monitoring, aquatic ecosystem, EMAP, nutrient supply, remote sensing, ecological exposure, ecological effects, watershed management, ecosystem assessment, N deposition, temperate forest ecosystems, nutrient flux, forest ecosystem, spatial scale, forest ecosystems, modeling, Chesapeake Bay watershed, conservation, environmental consequences, regional scale impacts, ecological assessment, ecological impacts, ecosystem management, gypsy moth, regional scale, terrestrial, aquatic ecosystems, water quality, nitrogen compounds, assessment methods, stress responses, Environmental Monitoring and Assessment Program, integrated ecological assessment, remotely sensed data, defoliation, interactions, nutrient fluxes, land use, nitrogen, Environmental Monitoring & Assessment Program, indicators, Chesapeake Bay

    Progress and Final Reports:

    Original Abstract
  • 1998
  • 1999 Progress Report
  • 2001 Progress Report
  • Final Report