Browsing by Author "Brazner, John"

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    Environmental Indicators for the Coastal Region of the U.S. Great Lakes
    (University of Minnesota Duluth, 2006) Niemi, Gerald J; Axler, Richard P; Brady, Valerie; Brazner, John; Brown, Terry; Ciborowski, Jan H; Danz, Nicholas P; Hanowski, JoAnn M; Hollenhorst, Thomas; Howe, Robert; Johnson, Lucinda B; Johnston, Carol A; Reavie, Euan D; Simcik, Matthew; Swackhamer, Deborah L.
    The goal of this research collaboration was to develop indicators that both estimate environmental condition and suggest plausible causes of ecosystem degradation in the coastal region of the U.S. Great Lakes. The collaboration consisted of 8 broad components, each of which generated different types of environmental responses and characteristics of the coastal region. These indicators included biotic communities of amphibians, birds, diatoms, fish, macroinvertebrates, and wetland plants as well as indicators of polycyclic aromatic hydrocarbon (PAH) photo-induced toxicity and landscape characterization. These components are summarized below and discussed in more detailed in 5 separate reports (Section II). Stress gradients within the U.S. Great Lakes coastal region were defined from 207 variables (e.g., agriculture, atmospheric deposition, land use/land cover, human populations, point source pollution, and shoreline modification) from 19 different data sources that were publicly available for the coastal region. Biotic communities along these gradients were sampled with a stratified, random design among representative ecosystems within the coastal zone. To achieve the sampling across this massive area, the coastal region was subdivided into 2 major ecological provinces and further subdivided into 762 segment sheds. Stress gradients were defined for the major categories of human-induced disturbance in the coastal region and an overall stress index was calculated which represented a combination of all the stress gradients. Investigators of this collaboration have had extensive interactions with the Great Lakes community. For instance, the Lake Erie Lakewide Area Management Plan (LAMP) has adopted many of the stressor measures as integral indicators of the condition of watersheds tributary to Lake Erie. Furthermore, the conceptual approach and applications for development of a generalized stressor gradient have been incorporated into a document defining the tiered aquatic life criteria for defining biological integrity of the nation’s waters. A total of 14 indicators of the U.S. Great Lakes coastal region are presented for potential application. Each indicator is summarized with respect to its use, methodology, spatial context, and diagnosis capability. In general, the results indicate that stress related to agricultural activity and human population density/development had the largest impacts on the biotic community indicators. In contrast, the photoinduced PAH indicator was primarily related to industrial activity in the U.S. Great Lakes, and over half of the sites sampled were potentially at risk of PAH toxicity to larval fish. One of the indicators developed for land use/land change was developed from Landsat imagery for the entire U.S. Great Lakes basin and for the period from 1992 to 2001. This indicator quantified the extensive conversions of both agricultural and forest land to residential area that has occurred during a short 9 year period. Considerable variation in the responses were manifest at different spatial scales and many at surprisingly large scales. Significant advances were made with respect to development of methods for identifying and testing environmental indicators. In addition, many indicators and concepts developed from this project are being incorporated into management plans and U.S. 8 EPA methods documents. Further details, downloadable documents, and updates on these indicators can be found at the GLEI website - http://glei.nrri.umn.edu.
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    Environmental Indicators for the US. Great Lakes Coastal Region
    (University of Minnesota Duluth, 2006) Niemi, Gerald J; Axler, Richard P; Brady, Valerie; Brazner, John; Brown, Terry; Ciborowski, Jan H; Danz, Nicholas P; Hanowski, JoAnn M; Hollenhorst, Thomas; Howe, Robert; Johnson, Lucinda B; Johnston, Carol A; Reavie, Euan D; Simcik, Matthew; Swackhamer, Deborah L.
    The goal of this research collaboration was to develop indicators that both estimate environmental condition and suggest plausible causes of ecosystem degradation in the coastal region of the U.S. Great Lakes. The collaboration consisted of 8 broad components, each of which generated different types of environmental responses and characteristics of the coastal region. These indicators included biotic communities of amphibians, birds, diatoms, fish, macroinvertebrates, and wetland plants as well as indicators of polycyclic aromatic hydrocarbon (P AH) photo-induced toxicity and landscape characterization. These components are summarized below and discussed in more detailed in 5 separate reports (Section II). Stress gradients within the U.S. Great Lakes coastal region were defined from 207 variables (e.g., agriculture, atmospheric deposition, land use/land cover, human populations, point source pollution, and shoreline modification) from 19 different data sources that were publicly available for the coastal region. Biotic communities along these gradients were sampled with a stratified, random design among representative ecosystems within the coastal zone. To achieve the sampling across this massive area, the coastal region was subdivided into 2 major ecological provinces and further subdivided into 762 segment sheds. Stress gradients were defined for the major categories of human-induced disturbance in the coastal region and an overall stress index was calculated which represented a combination of all the stress gradients. Investigators of this collaboration have had extensive interactions with the Great Lakes community. For instance, the Lake Erie Lakewide Area Management Plan (LAMP) has adopted many of the stressor measures as integral indicators of the condition of watersheds tributary to Lake Erie. Furthermore, the conceptual approach and applications for development of a generalized stressor gradient have been incorporated into a document defining the tiered aquatic life criteria for defining biological integrity of the nation's waters. A total of 14 indicators of the U.S. Great Lakes coastal region are presented for potential application. Each indicator is summarized with respect to its use, methodology, spatial context, and diagnosis capability. In general, the results indicate that stress related to agricultural activity and human population density/development had the largest impacts on the biotic community indicators. In contrast, the photoinduced P AH indicator was primarily related to industrial activity in the U.S. Great Lakes, and over half of the sites sampled were potentially at risk of P AH toxicity to larval fish. One of the indicators developed for land use/land change was developed from Landsat imagery for the entire U.S. Great Lakes basin and for the period from 1992 to 2001. This indicator quantified the extensive conversions of both agricultural and forest land to residential area that has occurred during a short 9 year period. Considerable variation in the responses were manifest at different spatial scales and many at surprisingly large scales. Significant advances were made with respect to development of methods for identifying and testing environmental indicators. In addition, many indicators and concepts developed from this project are being incorporated into management plans and U.S. EPA methods documents.
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    Regional, Watershed, and Site-Specific Environmental Influences on Fish Assemblage Structure and Function in Western Lake Superior Tributaries
    (2005) Brazner, John; Tanner, Danny K; Detenbeck, Naomi E; Batterman, Sharon L; Stark, Stacey L; Jagger, Leslie A; Snarski, Virginia M
    This report assesses the impact of human activities and forest fragmentation on fish communities in the western Lake Superior basin. Human-induced activities noted in the report included temperature changes, siltation, erosion, forest cover and forest manipulation, and invasive species. Specific results are reproduced below. “The relative importance of regional, watershed, and in-stream environmental factors on fish assemblage structure and function was investigated in western Lake Superior tributaries. We selected 48 second- and third-order watersheds from two hydrogeomorphic regions to examine fish assemblage response to differences in forest fragmentation, watershed storage, and a number of other watershed, riparian, and in-stream habitat conditions. Although a variety of regional, fragmentation, and storage-related factors had significant influences on the fish assemblages, water temperature appeared to be the single most important environmental factor. We found lower water temperatures and trout–sculpin assemblages at lower fragmentation sites and higher temperatures and minnow–sucker–darter assemblages as storage increased. Factors related to riparian shading and flow separated brook trout streams from brown trout (Salmo trutta) – rainbow trout (Oncorhynchus mykiss) streams. Functionally, fish assemblages at lower fragmentation sites were dominated by cold-water fishes that had low silt tolerance and preferred moderate current speeds, while fishes with higher silt tolerances, warmer temperature preferences, and weaker sustained swimming capabilities were most common at higher storage sites. Our results suggest that site-specific environmental conditions are highly dependent on regional- and watershed-scale characters and that a combination of these factors operates in concert to influence the structure and function of stream fish assemblages. Key points: This study was completed within 160 km of Duluth, Minnesota, in the Northern Lakes and Forests Ecoregion and within two ecological units, the North Shore Highlands (north shore streams) and the Lake Superior Clay Plain (south shore streams)which provided excellent contrast in hydrogeomorphic types. Functionally, south shore fishes tended to be silt-dwelling, trophic generalists with slow current preferences and a tendency towards nest-guarding spawning behavior. North shore fishes tended to be single-bout spawners with fast current preferences. From a management perspective, our results suggest that both timber management and wetland restoration or degradation decisions will need to be considered by resource managers when fish community health is a concern. For example, increasing percentages of mature forest cover should allow for salmonid–sculpin assemblages to become more prevalent in streams with the potential for cool or cold waters. Similarly, increased wetland cover should allow for a greater predominance of healthy warmwater fish assemblages assuming that other landscape features are not too badly degraded. By understanding the species structure and functional character of an assemblage and its relationship to landscape features, managers should be able to make at least a rough assessment of watershed condition. Lacking fish data, it might be easier to simply characterize forest cover and storage as a first step in identifying which watersheds likely contain streams that are degraded. Our results suggest that although in-stream habitat rehabilitation should continue to be used an important tool to improve biological conditions in streams, restoration efforts will have greater success if the potential interactions with landscape conditions are factored into the decision-making process. In some situations, manipulation of forest cover or watershed storage may have a greater impact on fish assemblage integrity than in-stream habitat improvements.”