Browsing by Subject "spiny water flea"

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    Data in support of Quantifying the effectiveness of three aquatic invasive species prevention methods
    (2023-05-04) Angell, Nichole R; Campbell, Tim; Brady, Valerie; Bajcz, Alex; Kinsley, Amy; Doll, Adam; Dumke, Josh; Keller, Reuben; Phelps, Nicholas BD; nangell@glc.org; Angell, Nichole R; Minnesota Aquatic Invasive Species Research Center (MAISRC)
    Efforts to prevent the spread of aquatic invasive species (AIS) have been widely implemented at many scales to mitigate economic and environmental harms. Boater education, watercraft inspection, and hot water decontamination are popular strategies for prevention of AIS moving through the recreational boating pathway. However, few studies have actually quantified the effectiveness of these strategies under field conditions. We estimated their effectiveness based on the performances of boaters, watercraft inspectors, and hot water decontaminators. Participants (n=144) were recruited at 56 public water access sites in Minnesota and 1 in Wisconsin. Each participant was asked to inspect and remove AIS from a boat staged with macrophytes, dead zebra mussels, and spiny water fleas. The types and amounts of AIS removed were used to estimate the effectiveness of each prevention method. We observed that removal varied by type of AIS, with macrophytes being most commonly removed for all participants. There were also regional (metro and outstate) differences for some species perhaps due to awareness and education. Hot water decontamination was the most effective (83.7%) intervention but was not significantly better at reducing risk of spread than was watercraft inspection (79.2%). Boaters were less effective at AIS removal (56.4%). Our results suggest that watercraft inspection is an effective prevention method for most boats, and that hot water decontamination is an important tool for high-risk boats. However, robust decontamination protocols are difficult to effectively execute. Furthermore, our results provide insights into how to increase boater awareness of often-overlooked locations and help reduce risk when inspectors cannot be present at a public water access site.
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    Long-Term Population Growth And Food Web Impacts Of The Spiny Water Flea (Bythotrephes Longimanus) Revealed From Sediment Records
    (2020-03) DeWeese, Nichole
    The spiny water flea (Bythotrephes longimanus) is an invasive predacious zooplankton species that has well-documented impacts on aquatic food webs. However, few studies have examined long-term population dynamics and food web impacts of the species. This study used Bythotrephes subfossils, as well as subfossils from potential prey and competitor taxa (bosminids, daphniids, Simocephalus, and Leptodora kindtii) and pigment concentrations in 210Pb dated sediment cores from Mille Lacs Lake and Kabetogama Lake in Minnesota, USA to estimate first invasion and population growth of Bythotrephes and corresponding impacts on the lower food web. Bythotrephes evidence was found nearly 100 years prior to first detection in each lake, potentially making these lakes the earliest invaded lakes in North America. Bythotrephes subfossils slowly accumulated until around 1990, when accumulation rates rapidly increased. Two-piece linear models provided a good fit for Bythotrephes annual accumulation rates (a proxy for population size), and modelled lag phases lasted approximately 70 years in each lake. Of the native zooplankton species, Bosmina was the only species group that declined in correspondence with Bythotrephes population growth. Bosmina antennules and mucros were measured to analyze if morphological changes occurred as Bythotrephes populations grew, but these feature lengths did not consistently change over time. Sediment pigment concentrations did not increase with Bythotrephes population growth as expected in either lake. This research suggests that 1) Bythotrephes could be present in lakes decades before detection in zooplankton net samples, 2) populations take several decades to overcome lag phases, and 3) that other ecosystem factors may be more important than Bythotrephes in driving long-term food web changes in these lakes.