Grantee Research Project Results
1998 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, 1997 through September 30, 1998
Project Amount: $1,697,104
RFA: Ecological Assessment (1996) RFA Text | Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Aquatic Ecosystems
Objective:
The primary goals of this project are 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. 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. Environmental properties we are addressing are aquatic and terrestrial biological diversity (species and landscape scales), tree growth and forest productivity, soil nitrogen and carbon content, and streamflow variability. To achieve these objectives, we are combining analysis of existing spatial and time-series datasets with the development of computer modeling and visualization tools that allow integration of data collected at multiple scales, as well as integration of climatic, hydrologic, and ecological processes.
Progress Summary:
During the second year of the project, we have completed all of the planned field work and made significant progress in data analysis, hypothesis testing, and model development. At our smallest, most intensively sampled research site, the Oak Ridge Reservation, we are proceeding with analysis of the long-term forest inventory dataset from Walker Branch Watershed, where variation in forest productivity and structure has been affected strongly by the El Nino?Southern Oscillation (ENSO) precipitation cycles over the past 30 years. Preliminary results indicate a strong ENSO-related decline in growth of some species, but overall stability for the forest as a whole. A graduate student is developing a high resolution spatiotemporal record of tree growth on Walker Branch Watershed using tree-ring analysis of Liriodendron tulipifera, one of the most drought sensitive species on the watershed.
Analysis of long-term datasets of fish and benthic insect communities in Bear Creek on the Oak Ridge National Environmental Research Park indicates strong physical regulation of both population and community structure, consistent with the predictions of the dynamic equilibrium model for disturbance-driven systems. Preliminary results indicate significant patterns related to: (1) differences between the diversity dynamics of certain functional groups of organisms and that of the entire community; (2) strong nestedness of community structure, with the highest number of species at the downstream sites; and (3) reversal of population and community responses to flow variation between upstream and downstream sites. Strong flow-related interannual variation in species distributions and diversity suggests caution in the use of diversity indices as indicators of anthropogenic impacts in first through third order streams, at least in this region.
Results of our own research and analyses, as well an ongoing literature review, 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. A major focus of our work is understanding the conditions under which natural variability in ecosystem processes can be increased (i.e., destabilized) or decreased (i.e., stabilized) by changes in environmental conditions that are not the direct cause of the variability. Our work on multiple resource interactions includes both simulation modeling and analysis of published data, and has led to the identification of a potential mechanism for alteration of natural patterns of spatiotemporal variability, which we call the "variance amplification hypothesis."
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, Aarssen LW, Austin MP, Cade BS, Fridley JD, Garnier E, Grime JP, Hodgson J, Lauenroth WK, Thompson K, Vandermeer JH, Wardle DA. No consistent effect of plant diversity on productivity. Science 2000;289(5483):1255a. |
R825157 (1998) R825157 (Final) |
Exit Exit |
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Huston M, Scurlock J, Huston A. Shifting the carbon balance. Bioscience 2000;50(4):292. |
R825157 (1998) |
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, modeling, dynamic equilibrium model, exotic species, wildlife models, nonequilibrium, environmental gradients, biodiversity, land use impacts, simulation models., RFA, Air, Geographic Area, Ecosystem Protection/Environmental Exposure & Risk, Ecosystem/Assessment/Indicators, Ecosystem Protection, exploratory research environmental biology, Chemical Mixtures - Environmental Exposure & Risk, climate change, Ecological Effects - Environmental Exposure & Risk, Monitoring/Modeling, 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.