Browsing by Subject "Macroinvertebrate"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    The effects of fluid flow on the spatial density, distribution, and metabolism of larval Glossosoma
    (2013-05) Morris, Mark William Lehnardt
    The focus of this research was the mechanistic relationship between fluid flow, spatial density, distribution, and metabolism of stream-dwelling insect larvae of the caddisfly genus Glossosoma (Glossosomatidae: Trichoptera). Glossosoma are ecologically important for many reasons, including that they are dominant grazers in lotic food webs, are capable of suppressing stream periphyton, and act as an indicator of stream health. A description is herein presented of fluid flow and stream bathymetry environments where Glossosoma are often present. Predictive relationships for Glossosoma spatial density are proposed from local fluid flow and channel bathymetry variables. The research was conducted through a series of four separate studies. First, habitat was quantified for larval Glossosoma in three coastal mountain streams in northern California. Applying dimensional analysis, a functional relationship was developed for predicting larval abundance. Variogram analysis of Glossosoma spatial density and bed topography revealed overlap in the separation distance above which point measurements were statistically independent. Second, field measurements were conducted in Valley Creek, Minnesota and data were compared with the measurements in the coastal mountain streams. Third, a computational model was employed to estimate high resolution fluid flow variables along a riffle in Valley Creek. Simulation results were verified and implemented in a predictive model for Glossosoma abundance. Fourth, a laboratory study of Glossosoma metabolism under varying flow conditions revealed generally increasing oxygen consumption with increasing fluid flow velocities. The proposed research will be instrumental for predicting not only how Glossosoma respond to changes in fluid flow and stream bathymetry conditions, but also how these variables influence larval spatial density, distribution, and behavior in lotic environments.
  • Thumbnail Image
    Item
    Identifying The Impacts Of Excess Fine Sediment On Benthic Macroinvertebrate Communities
    (2016-03) Herrera, Larissa
    Many streams throughout the United States are negatively impacted by excess fine sediments (sand, silt, and clay). Benthic macroinvertebrates are a commonly-used tool to assess stream condition; however, current methodologies typically are not able to distinguish among stressors. Previous studies have correlated macroinvertebrate communities and traits with excess fine sediments, demonstrating that aquatic macroinvertebrates are sensitive to deposited fine sediment and the assemblages will shift in response. Western Lake Superior streams have a wide range of fine sediment amounts due to clay and sand soils, but have low amounts of other stressors, and thus are a good region to investigate relationships between macroinvertebrate traits and fine sediments. Data were collected from 22 stream sites located along the north shore of Lake Superior in 2010. The data collected in 2010 did not have the desired gradient of fine sediment due to wet conditions that year; therefore, the data were supplemented with data collected by NRRI personnel in earlier years (1997 – 2008). The five sediment stressors used in analyses included percent embeddedness, depth of fine sediments, total percent fine sediments, percent sand, and a combined sediment index created using normalized and transformed embeddedness, depth of fine sediments and total percent fine sediments. Fifty-seven specific taxonomic groups and macroinvertebrate physical and behavioral characteristics (traits) were tested as potential response metrics in linear regressions. In addition, TITAN analyses were used to look for thresholds or sediment stressor values at which a taxon increases greatly, decreases greatly, or disappears from a community. Both the linear regressions and TITAN analyses showed a change in the community structure under conditions of excess sediment in the form of embeddedness, total fines, depth of fines, and/or the combined sediment index. The TITAN analyses also showed a change in the community structure due to increasing proportion sand in the streambed. Furthermore, the analyses identified potential characteristics that may specifically make a particular macroinvertebrate more or less vulnerable to excess fine sediments.
  • Thumbnail Image
    Item
    St. Louis River Watershed Streams & Lakes: Water Quality/Biological Monitoring
    (University of Minnesota Duluth, 2011-06-29) Axler, Richard P; Breneman, Dan; Brady, Valerie; Johnson, Lucinda B; Ruzycki, Elaine; Henneck, Jerald; Olker, Jennifer; Host, George E; Brown, Terry; Bartsch, Will
    This provisional report is an addendum to the Surface Water Assessment Final Report entitled Surface Water Assessment St. Louis River Watershed: Streams and Lakes: Water quality/biological monitoring submitted to the MPCA electronically on June 29, 2011. That final report summarizes the water quality, habitat, macroinvertebrate, and fish data previously submitted to MPCA as the major part of this SWA project. This provisional report represents a detailed summary of the statistical analyses that the Natural Resources Research Institute (NRRI) at the University of Minnesota-Duluth is conducting using the data collected from this project together with previous and ongoing landscape stressor analyses conducted by NRRI via other funding sources over the past several years.