Grantee Research Project Results
1999 Progress Report: Ecological Indicators for Large River-Floodplain Landscapes
EPA Grant Number: R826600Title: Ecological Indicators for Large River-Floodplain Landscapes
Investigators: Turner, Monica G. , Stanley, Emily H.
Institution: University of Wisconsin - Madison
EPA Project Officer: Packard, Benjamin H
Project Period: October 1, 1998 through September 30, 2001 (Extended to September 30, 2002)
Project Period Covered by this Report: October 1, 1998 through September 30,1999
Project Amount: $677,351
RFA: Ecological Indicators (1998) RFA Text | Recipients Lists
Research Category: Aquatic Ecosystems
Objective:
Identifying landscape indicators that are well correlated with specific aspects of ecological function is a crucial research need requiring an integrated approach that combines landscape monitoring with field studies. Large river-floodplain systems are among the most diverse and dynamic landscapes, providing many important societal values, but relatively little effort has been devoted to the development and testing of landscape indicators for these systems. We are developing and testing ecological indicators (population, community, ecosystem, and landscape) for large river-floodplain landscapes along reaches of the Wisconsin River. We are addressing two main questions:
- Which landscape metrics are most useful for monitoring population, community, and ecosystem processes in large river-floodplain landscapes? Spatially extensive field sampling is being combined with landscape analysis in six reaches of the Wisconsin River sampling to quantify the ability of landscape indicators to predict ecological variables over broad scales. Landscape indicators will be evaluated by their utility for detecting changes in the structure and function of the Wisconsin River floodplain landscape resulting from modification of the natural flow regime, historical land use, and current land-use patterns.
- What are the constraints on extrapolating relationships between landscape metrics and ecological processes in large river-floodplain landscapes? We will use field data, landscape analysis, and simulation modeling to evaluate the constraints on spatial and temporal extrapolation of landscape indicators by: (1) predicting and testing population, community, and ecosystem indicators for the Wisconsin River floodplain landscape based on landscape indicators in new study landscapes; (2) determining whether there are thresholds in landscape pattern beyond which ecological processes change qualitatively; and (3) assessing the sensitivity of ecological indicators to landscape changes.
Progress Summary:
The first year of this project included finalization of field study sites, completion of the first season of field work, acquisition and interpretation of historical aerial photography, compilation of spatial databases, and data entry. Two post-doctoral research associates (Drs. James Miller and Hojeong Kang) joined the project along with four graduate students (Mark Dixon, Sarah Gergel, Ross Freeman, and Jonathon West).
During winter and spring 1999, we finalized the selection of study reaches on the Wisconsin River, relying on maps and aerial photographs. Boundaries of the 100-year floodplain were then identified and digitized for each study reach. Potential locations for field sampling transects were identified for each of the six reaches to be sampled during the first field season. Based on the widths of floodplain forests and the amount of separation between plots needed for bird sampling, it was decided that transects would contain five plots separated by 120-m intervals. Private landowners and state and nongovernmental organizations were contacted to secure permission for field sampling.
Field work extended from late May through mid-July 1999. A total of 220 plots located along 44 transects were sampled within the six study reaches. Precise locations of each plot were obtained using a global positioning system (GPS). Vegetation was sampled within a 10 m x 20 m plot in which each tree was identified to species and its diameter-at-breast-height recorded. All shrubs and saplings were identified to species and censussed, and overall canopy cover and shrub cover were estimated for each plot. Seedling abundance, slope position, herbaceous cover, and leaf litter were recorded within each of three randomly located 1-m2 quadrants. Within three additional 100-cm2 randomly located quadrants, litter accumulation was assessed by collecting surface organic matter, and three soil cores were obtained to estimate potential denitrification rates and characterize soil conditions. Data entry and initial analyses are now in progress.
Birds were censussed at each plot using 8-minute point counts, during which all birds seen and heard were noted. The best time to census birds during the breeding season is during the early morning hours, but individual species vary, both with regard to breeding dates and time of the morning for greatest activity. Therefore, each transect was visited twice, with the second round commencing only after all transects had been censussed once. For each transect, the first of the two censuses began at dawn and the second census began at approximately 0900 hours; a different observer conducted each of the two censuses on a transect to avoid any observer-related biases. These first-year data have been entered and proofread, and we are now beginning the analysis phase. In this first field season, we counted 70 species and 4,870 individual birds.
Initial analyses for microbial activity and soil organic matter have been completed. Preliminary results suggest that microbiological indices can be explained by several ecological processes that operate at different spatial scales. At the landscape scale, for example, microbial activity appears to be influenced by land cover, whereas the presence of levees may be a more important determinant at the scale of individual transects. At finer scales, significantly different enzyme activities were found in soils under different types of trees. Microbial processes play a pivotal role in determining the ecological integrity of floodplain ecosystems, and these results suggest that changes in land-use pattern, construction or removal of levees, or changes in dominant tree species all play a role in affecting these processes.
Initial analyses of the bird census data revealed similarity among the bird communities associated with each study reach, with an average of 70?80 percent of the species shared between reaches on a pairwise basis. Numbers of individual birds, however, were quite variable, with the three southern-most reaches containing approximately 30 percent more birds than the three northern-most reaches. We suspect that birds differing in their use of foraging or nesting sites and substrates (i.e., different guilds) will be influenced by different factors that operate at different scales. Woodpeckers, for example, require dead trees for nesting and foraging, and seven species occurred at our study sites. The number of woodpeckers, however, decreased from the southern-most reach to the northern-most reach, both in terms of species and individual birds. Surprisingly, some species that are generally associated with habitats in northern Wisconsin were only detected at our southern-most reaches, suggesting that land use or river flow modifications (as opposed to determinants operating at geographical scales) may exert a strong influence on this group of birds.
In addition to compiling and analyzing data on vegetation, soil, and birds, we have recently been joined by a third postdoctoral researcher (Dr. Matthias Burgi) who is focusing on the historical aspects of our study areas with independent funding. Relevant sources of historical information currently are being collected and evaluated. These data include written records, photographs, and maps of landownership, vegetation, and land use. We believe that a historical perspective will prove invaluable in gaining a better understanding of the factors underlying current ecological patterns in floodplain forests.
Future Activities:
During the coming year, we will: (1) complete analyses of the field data obtained in six river reaches during the 1999 field season (bird censuses, vegetation sampling, denitrification, and microbial activity) in relation to landscape indicators; (2) complete the interpretation of historical and recent aerial photography for study reaches in the 1930s, 1960s, and 1990s; (3) conduct the second season of field sampling; and (4) begin developing the models and analyses required to address the questions associated with extrapolating relationships between landscape metrics and ecological processes. In addition, personnel associated with the project will be giving presentations on this research at several national and international meetings (U.S. Chapter of the International Association for Landscape Ecology, Ecological Society of America, North American Benthological Society, and American Society for Limnology and Oceanography). We anticipate two graduate student theses to be completed during the coming year, and the first manuscripts derived from this work to be submitted to peer-reviewed journals.
Journal Articles on this Report : 3 Displayed | Download in RIS Format
Other project views: | All 58 publications | 16 publications in selected types | All 16 journal articles |
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Dixon MD, Turner MG. Seedling distribution on Wisconsin River sandbars:controls at different spatial scales. ECOLOGICAL MONOGRAPHS. 2002; 72:465-485. |
R826600 (1999) |
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Freeman RE, Stanley EH, Turner MG. Analysis and conservation implications of landscape change in the Wisconsin River floodplain, USA. Ecological Applications 2003;13(2):416-431. |
R826600 (1999) R826600 (2000) R826600 (2001) R826600 (Final) |
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Gergel SE, Dixon MD, Turner MG. Consequences of human-altered floods: levees, floods, and floodplain forests along the Wisconsin River. Ecological Applications 2002;12(6):1755-1770. |
R826600 (1999) R826600 (2000) R826600 (2001) R826600 (Final) |
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Supplemental Keywords:
water, watersheds, soil, land, ecosystem, indicators, ecological effects, regionalization, scaling, habitat, ecology, remote sensing, Midwest., RFA, Scientific Discipline, Geographic Area, Ecosystem Protection/Environmental Exposure & Risk, Ecosystem/Assessment/Indicators, Ecosystem Protection, exploratory research environmental biology, State, Ecological Effects - Environmental Exposure & Risk, Ecology and Ecosystems, Ecological Risk Assessment, Ecological Indicators, ecological exposure, landscapes, anthropogenic stresses, habitat, remote sensing, landscape indicator, Midwestern U.S., large river floodplain landscapes, Wisconsin (WI)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.