Browsing by Subject "St. Louis River Estuary"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Coastal Wetland Monitoring Survey Report: Clough Island
    (University of Minnesota Duluth, 2014-06) Dumke, Josh; Brady, Valerie; Danz, Nicholas P; Bracey, Annie; Niemi, Gerald J
    Better than average water quality at Clough Island wetlands (for chloride and conductivity), as compared to most other SLR estuary wetlands, demonstrates the island's distance from human development. However, these wetlands still are located in the St. Louis River estuary, and thus have poorer quality by many measures than nearby Lake Superior wetlands. In particular, Clough Island wetlands had poorly-developed wet meadow zones compared to Lake Superior wetlands. Most of the Clough Island wetland areas were dominated by an emergent vegetation zone. Submergent vegetation was very patchy, and research by US EPA (Angradi, pers. comm.) found that SAV abundance across the whole estuary varies yearly depending on turbidity levels. In addition, Island wetlands have higher exposure to wind and wave action than do wetlands in secluded bays, which also affects the development of extensive aquatic vegetation beds. Clough wetlands had both high quality and low quality vegetation species, with purple loosestrife and invasive cattail particularly prevalent at 1089. Therefore, floristic quality values were very similar to other estuary sites, but lower than nearby Lake Superior wetlands that had fen components. Clough Island wetland fyke net fish catches were skewed toward warmer water fish (e.g., sunfish) than nearby Lake Superior sites, and water temperatures were substantially higher in the SLR estuary than in Lake Superior wetlands. Clough Island wetland site 1089 also had the most invasive tubenose gobies comprising a fish catch. In contrast, site 1089 had the greatest fish taxa richness. Clough Island wetlands did not provide as much habitat for YOY fish as did highly vegetated, secluded bays. Site 1102 had the greatest number of habitats and included a floating bog mat. Thus, macroinvertebrate richness was highest at site 1102, and more sensitive macroinvertebrates were present at this site. Site 1201 had the fewest habitats, and it had the lowest taxa richness for fish and macroinvertebrates (although sampling effort was also lowest at this site due to the lack of habitats). An invasive, non-native snail (Bithynio, the faucet snail) was found in all wetlands, but made up 7% of the macroinvertebrates collected from site 1201. This was different from nearby Lake Superior wetlands, in which no invasive macroinvertebrates were found. Bird use at Clough Island was different in some ways from other estuary wetlands. Wind and wave exposure and lack of protection may explain why migrating waterfowl and waterbirds were less commonly observed at Clough Island wetlands relative to other estuary wetlands. However, the island's isolation, lack of human usage, and potential for lower numbers of predators may benefit breeding birds, and forest-dwelling songbirds that were detected in large numbers during the breeding season. This idea is reinforced by the detection of secretive marsh birds and the foraging by Common Tern.
  • Thumbnail Image
    Item
    Lake Superior Common Tern Conservation Final Report
    (University of Minnesota Duluth, 2016-12-22) Bracey, Annie; Niemi, Gerald J; Cuthbert, Francesca J
    Since its creation, Interstate Island has lost approximately two acres of useable tern nesting habitat, primarily due to wind and water erosion. In 2015, the Minnesota Department of Natural Resources (DNR) added 3,000 cubic yards of clean sand and pebbles to the island to mitigate the effects of erosion and fluctuating water levels, which has caused seasonal flooding of nesting sites. This restoration effort should make the island more suitable for nesting Common Terns, although more restoration work is needed. Interstate Island is a Wildlife Management Area jointly managed by the Minnesota and Wisconsin Departments of Natural Resources (DNR), with the primary objective of providing suitable nesting habitat for colonial waterbirds. Since 1990, this has been the only nesting location of Common Terns in the St. Louis River Estuary with roughly 200 breeding pairs. Interstate Island is also the primary breeding location of Ring-billed Gulls (Larus delawarensis) in the area, with an estimated 13,000 breeding pairs. The rapidly increasing population of Ring-billed Gulls has drastically reduced available breeding habitat for Common Terns. This species competes for breeding space with terns, depredates eggs, and preys on tern chicks. In some years the colony has had total nest failure, primarily due to intense predation by gulls.
  • Thumbnail Image
    Item
    Stressor Gradients and Spatial Narratives of the St. Louis River Estuary
    (University of Minnesota Duluth, 2014-06-01) Host, George E; Axler, Richard P; Hagley, Cynthia; Drewes, Annette; Bartsch, Will; Henneck, Jerald; Fortner, Rosanne
    The St. Louis River Estuary, a recently designated National Estuarine Research Reserve, is a complex mosaic of high quality aquatic habitat intermingled with areas of heavy industrial use, contaminated sediments, and effluents from the surrounding urban landscape. The estuary is Lake Superior’s largest U.S. tributary and home to the Duluth-Superior international seaport. The NOAA Sea Grant Program plays a significant role in promoting education, outreach and stewardship in Great Lakes coastal communities and environments. Geospatial thinking can enhance Sea Grant’s objectives, yet few tools exist to foster such an approach on a regional scale. In this project we conducted an estuary-wide sampling of water quality, wetland vegetation and macroinvertebrates, based on an anthropogenic stressor gradient that stratified sites from the relatively undisturbed riverine upper estuary to the working industrial and commercial harbor. Macroinvertebrate communities, plant communities, and water quality all showed some degree of association with the stressor gradient. The 17 water quality parameters we measured included five usually associated with suspended particulates and the rest with the “dissolved fraction” of the water. Dissolved “bioavailable” nitrogen (ammonium and nitrate), chloride, and specific electrical conductivity (a measure of total dissolved salts) were positively correlated with increased environmental stress (Bartsch 2012; Bartsch et al. submitted to JGLR 6/2014) as were suspended sediment and the sediment- associated parameters turbidity, water clarity, and total phosphorus when a factor relating to soil erosion potential was added to the original stressor gradient. These associations were evident for multiple combinations of flow regime and location in tributaries and at near-shore locations within the estuary. Wetland floristic quality was also negatively related to increasing human stress, with disturbed sites and industrial bays of the lower estuary having a greater prevalence of invasive plants and species tolerant of elevated nutrients and sediments. Conversely, sheltered bays and fringing marshes of the upper estuary had lower stress and higher floristic quality. In terms of macroinvertebrates, the Ephemoroptera or mayflies, a common indicator of environmental quality, showed a decline in abundance with increasing overall stress. Overall, these field efforts indicated good potential for developing more robust predictive models as more data becomes available and by improving the spatial resolution of some of the stressor elements - especially soil erosivity and NPDES discharges. By integrating scientific research with spatial narratives, geoquests and deep maps, we created socially and spatially rich tools to increase environmental literacy of the region. Spatial narratives for the St. Louis River Estuary were captured through five vignettes of key activities important to the area: fishing, shipping, wild ricing, recreation, and community; and through perspectives of the local people who told their stories about places and experiences related to these activities. Our research connected aquatic science research on human-based stressor gradients with spatially explicit vignettes of local resource issues and place-based games around those local issues to enhance spatial awareness, engagement with, and stewardship of the estuary.