Grantee Research Project Results
1999 Progress Report: Land Use and Geomorphic Indicators of Biotic Integrity in Piedmont Streams
EPA Grant Number: R826597Title: Land Use and Geomorphic Indicators of Biotic Integrity in Piedmont Streams
Investigators: Leigh, D. S. , Kramer, E. A. , Freeman, Mary C. , Rosemond, A. D. , Freeman, Byron J. , Pringle, Catherine M.
Institution: University of Georgia
EPA Project Officer: Packard, Benjamin H
Project Period: January 1, 1999 through December 31, 2001
Project Period Covered by this Report: January 1, 1999 through December 31, 2000
Project Amount: $780,834
RFA: Ecological Indicators (1998) RFA Text | Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Aquatic Ecosystems
Objective:
The main objective of this research is to define the predictive capabilities of scale-variable attributes of land cover (GIS-based) and geomorphology as risk assessment indicators of biotic integrity of stream ecosystems. The watershed under investigation is the Etowah River basin, north of Atlanta, Georgia. Land use influences hydrologic and sediment conditions that alter stream geomorphology, which is the physical template for stream ecosystems. Landscape alteration influences these physical stressors and occurs over large areas, within which streams networks are nested. Current land use manipulation is occurring in watersheds with different historical legacies. Given these various aspects of landscape change, this research is investigating several important questions: Do physical stressors and the corresponding ecological response vary as a function of land use? Is this relationship consistent within watersheds of vastly different sizes? Does antecedent land use (>50 years ago) influence the physical stressor and ecological response relationship? To answer these questions, the research is divided into two main projects: Year 1?a comprehensive survey of geomorphic condition and biological integrity in 30 streams draining watersheds of 3 distinct size classes (10 streams each in 15, 50, and 100 km2 watersheds) varying in land use from fully forested to approximately 50 percent urban; and Year 2?a detailed analysis of geomorphic alteration, stream habitat dynamics, and biotic integrity.Progress Summary:
We have selected 30 streams (10 each in 15, 50, and 100 km2 watersheds) and characterized the land use and geomorphic condition, and assessed biological integrity at each site. In general, 80 to 100 percent of proposed Year 1 tasks are complete, except for detailed analysis of raw data collected during the summer. Tasks that are not 100 percent complete required much more time for field work than was anticipated. These delays will not affect our decisions regarding selection of Year 2 study sites before the Year 2000 field season.
Landscape characterization consisted of estimating different land use within the watershed of each stream, as well as developing a number of landscape indices (e.g., road density, forest fragmentation indices). We have established a land use gradient in each of the watershed size classes. Nonforested land use ranged from 3 to 35 percent, 4 to 35 percent, and 3 to 41 percent of total land use in the 15, 50, and 100 km2 watersheds, respectively. Landscape analysis also indicated that areas of greater urban land cover are more fragmented and have greater road densities than less urbanized watersheds.
The proposed Year 1 geomorphic survey of the 30 stream channels is complete, except for detailed assessments of past sedimentation rates. In general, it was found that most streams are incised and the prevailing valley flat is a terrace. Watersheds that experienced most erosive past land use (row crop agriculture, forestry, urbanization) and thickest valley floor sedimentation exhibit greatest incision. Smallest watersheds (15 km2) tend to exhibit greatest lateral migration and incipient floodplain development, whereas larger streams function as incised large capacity channels that rarely flow overbank.
Stream chemistry changed along the gradient of land use. Phosphorus, ammonium, nitrate, and specific conductance all increase as a result of decreasing forested land use, but some of the responses show scale dependency.
Sampling of biological integrity was completed in August 1999 and processing and analysis of samples are expected to be completed by February 2000. Some preliminary analyses have been made. Insect bioindices were calculated for the 15 km2 sites. Indices were highly variable along the land use gradient within these streams and were not related to 1993 land use data. However, insect communities do appear to be related to current stream sediment characteristics, supporting a linkage between geomorphic condition and biotic response. Fish diversity was positively correlated to percent forested land use across all sites, but the strongest relationship was found in the 100 km2 watersheds, suggesting that there may be predictable community responses to land use change, but that it may be scale dependent.
We used two rapid bioassessment protocols to characterize stream habitat at all 30 sites. We used the Stream Visual Assessment Protocol (SVAP) developed in 1998 by the Natural Resources Conservation Service. We also employed the most recent version of the Environmental Protection Agency's (EPA) Rapid Habitat Assessment Protocol (RHAP) for use in streams and rivers. At least two individuals scored each site using both protocols. Preliminary analysis shows a strong correlation between SVAP and RHAP scores at one site. Habitat assessment scores are positively related to fish species richness at 100 km2 watershed sites. Correlations are lower for 50 km2 watershed sites and appear to be nonsignificant for 15 km2 watershed sites.
In addition to planned sampling, we sampled algae in both the spring (before leafout, April 8?19) and in the late summer (August 26?September 10) at each of the 30 sites. For each site, 10 samples were collected in the spring and 10 samples in the late summer. Each sample consists of three pooled, randomly selected samples collected from the dominant substrate every 10 m along a 100 m reach. Spring samples already have been processed for chlorophyll-A and ash free dry mass (AFDM); processing of summer samples will be completed by October 15, 1999. Algal community composition and biovolume will be assessed from subsamples preserved in 5 percent formalin.
Future Activities:
During this next year, the collection of Year 1 geomorphic condition data (sedimentation rate estimates) and the processing and analysis of insect and fish samples will be completed. By March 2000, the analysis of biotic and geomorphic responses to land use change will have been completed. After that analysis is complete, the 10 streams to be used in conducting Year 2 research will be identified. Through a more in-depth analysis of geomorphic alteration and habitat response, Year 2 research is designed to identify factors important in either mitigating or accentuating the impacts of land use change on biotic integrity. Water chemistry data will continue to be collected through April 2000 at all 30 sites, and then collapsed to focus on the 10 sites chosen for Year 2 work.Journal Articles:
No journal articles submitted with this report: View all 55 publications for this projectSupplemental Keywords:
ecology, geography, fluvial geomorphology, Georgia, GA, land use, watersheds., RFA, Scientific Discipline, Geographic Area, Water, Ecosystem Protection/Environmental Exposure & Risk, Ecology, Water & Watershed, exploratory research environmental biology, Environmental Chemistry, Ecosystem/Assessment/Indicators, Chemical Mixtures - Environmental Exposure & Risk, Ecosystem Protection, Monitoring/Modeling, Ecological Effects - Environmental Exposure & Risk, Ecological Effects - Human Health, Ecological Risk Assessment, Biology, Geology, EPA Region, Watersheds, Ecological Indicators, risk assessment, aquatic biota , landscape indicator, biodiversity, land use effects, stream ecosystems, ecosystem indicators, geomorphic indicators, soil, aquatic ecosystems, water quality, GIS, land useProgress 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.