Grantee Research Project Results
1999 Progress Report: Use of Multi-Scale Biophysical Models for Ecological Assessment Applications in the Southeastern United States
EPA Grant Number: R825157Title: Use of Multi-Scale Biophysical Models for Ecological Assessment Applications in the Southeastern United States
Investigators: Huston, Michael A. , Smoot, J. L.
Current Investigators: Huston, Michael A.
Institution: University of Tennessee
EPA Project Officer: Packard, Benjamin H
Project Period: October 1, 1996 through September 30, 1999
Project Period Covered by this Report: October 1, 1998 through September 30, 1999
Project Amount: $1,697,104
RFA: Ecological Assessment (1996) RFA Text | Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Aquatic Ecosystems
Objective:
Unless natural variability can be quantified and predicted for specific landscapes that have assessment or management issues, it will be impossible to determine whether environmental changes attributed to human activities are actually beyond the range that would be expected from natural variability alone. The primary goal of this project is to evaluate the dynamic equilibrium model of interacting processes that create landscape-scale patterns of spatial and temporal variability in major ecosystem properties, and to develop analytical tools for predicting these patterns.
Progress Summary:
Our analysis of spatiotemporal variation in tree growth, using both long-term forest inventory data and dendrochronological analysis, demonstrates why long-term spatially-spatially distributed data are essential for understanding and interpreting variability in ecological processes, which is the primary theme of this project. Not only does the "typical" growth rate of trees change from one climatic period to another (e.g., 1920?1960 versus 1960?1980), but the "optimal" conditions for a species shifts from one position on the landscape to another. The tree-ring analysis clearly shows that during wet periods the tulip poplars on Walker Branch Watershed grew most rapidly on ridgetop sites, while during dry periods the tulip poplars in the valley bottoms were growing fastest. The spatiotemporal dynamics of ecological processes reveal complexities that must be understood before environmental changes and anthropogenic impacts can be detected and interpreted. Similar phenomena were found in our analysis of aquatic data.
Results of our own research and analyses, as well as recent publications in the open literature, indicate that the dynamic equilibrium model provides a powerful framework for predicting the spatiotemporal patterns of community and ecosystem properties in both aquatic and terrestrial systems. Two major predictions of the dynamic equilibrium model (Huston, 1979; Huston, 1994) that are directly relevant to the objectives of this proposal have recently been validated. The central prediction of the model is that the effects of changing disturbance frequency on species diversity should REVERSE between productive and unproductive environments (and similarly with regard to changing productivity). Proulx and Mazumder (1998) conducted a meta-analysis of published studies on the effects of grazing and mowing on plant diversity (aquatic and terrestrial). They found that all of the studies conducted in unproductive, oligotrophic environments found that diversity DECREASED with increasing intensity of grazing, while in productive, eutrophic environments, most studies found that diversity INCREASED with increasing intensity of grazing. This response reversal has profound implications for the interpretation of diversity changes as an environmental indicator. The prediction that high diversity communities should be most susceptible to invasion by exotic species also has to be validated in publications this year.
Future Activities:
Objectives for the fourth-year, no-cost extension of the project are: (1) completion of all student theses and derived publications; (2) submission of papers based on all the data analysis that has been completed or is nearing completion; (3) analysis and publication of available data on forest structure at the scale of the Southern Appalachians; (4) review and synthesis papers summarizing major findings from the project; and (5) outreach for applications of the project's major concepts and computer tools to other issues and regions.
Journal Articles on this Report : 5 Displayed | Download in RIS Format
Other project views: | All 64 publications | 16 publications in selected types | All 13 journal articles |
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Type | Citation | ||
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Huston MA. Local processes and regional patterns: appropriate scales for understanding variation in the diversity of plants and animals. Oikos 1999;86(3):393-401. |
R825157 (1999) R825157 (Final) |
Exit |
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Huston MA. Microcosm experiments have limited relevance for community and ecosystem ecology: synthesis of comments. Ecology 1999;80(3):1088-1089. |
R825157 (1999) R825157 (Final) |
not available |
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Lafon CW, Graybeal DY, Orvis KH. Patterns of ice accumulation and forest disturbance during two ice storms in southwestern Virginia. Physical Geography 1999;20(2):97-115. |
R825157 (1998) R825157 (1999) R825157 (Final) |
not available |
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Lafon CW, Huston MA, Horn SP. Effects of agricultural soil loss on forest succession rates and tree diversity in east Tennessee. Oikos 2000;90(3):431-441. |
R825157 (1998) R825157 (1999) R825157 (Final) |
Exit |
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Lafon CW, Speer JH. Using dendrochronology to identify major ice storm events in oak forests of southwestern Virginia. Climate Research 2002;20(1):41-54. |
R825157 (1998) R825157 (1999) R825157 (Final) |
Exit |
Supplemental Keywords:
landscape, dynamic equilibrium model, disturbance, diversity, exotic species, wildlife models, nonequilibrium, environmental gradients, biodiversity, land use impacts, simulation models., RFA, Air, Geographic Area, Ecosystem Protection/Environmental Exposure & Risk, exploratory research environmental biology, Ecosystem/Assessment/Indicators, Chemical Mixtures - Environmental Exposure & Risk, Ecosystem Protection, climate change, Monitoring/Modeling, Ecological Effects - Environmental Exposure & Risk, Ecological Effects - Human Health, Southeast, Ecological Indicators, multi-scale biophysical models, geomorphology, environmental monitoring, aquatic biota , assessment models, climate change impact, ecosystem assessment, multi-level indicators, biodiversity, microclimatic conditions, hydrological, ecological assessment, aquatic ecosystems, soil carbon, landscape characterization, spatial and temporal patterns, climate variability, ecological researchRelevant Websites:
http://www.ornl.gov/ORNLReview/rev29_3/text/life.htm
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.