Browsing by Author "University of Minnesota Fisheries Systems Ecology Lab"

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    Data and R code supporting “Non-linear water clarity trends and impacts on littoral area in Minnesota lakes”
    (2021-04-19) Vitense, Kelsey; Hansen, Gretchen J A; viten003@umn.edu; Vitense, Kelsey; University of Minnesota Fisheries Systems Ecology Lab
    This repository contains the data and R code used to conduct the analyses in the article "Non-linear water clarity trends and impacts on littoral area in Minnesota lakes" in Limnology and Oceanography Letters.
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    Data in support of "Phenology, food webs, and fish: the effects of loss of lake ice across multiple trophic levels"
    (2025-02-21) Rounds, Christopher I; Manske, John; Feiner, Zachary S; Walsh, Jake R; Polik, Catherine A; Hansen, Gretchen J A; round060@umn.edu; Rounds, Christopher; University of Minnesota Fisheries Systems Ecology Lab
    This dataset and associated analyses are made to accompany the manuscript, "Phenology, food webs, and fish: the effects of loss of lake ice across multiple trophic levels". Accompanying data is split into components with distinct analyses (lake ice-off, phytoplankton, zooplankton, walleye spawning, walleye young-of-year recruitment, and walleye abundance). Plankton data is collected from Ramsey County, MN, USA lakes and filtered only to include open water season. Walleye spawning is collected by DNR staff as part of egg-take operations in the spring, walleye young-of-year recruitment is indexed by fall electrofishing and was filtered according to (Kundel et al. 2023). Walleye adult abundance is indexed through gillnets during the open water season and has minimum effort and sampling time of year filtering (see MNDNR 2017), unaged fish were applied a HALK to allow for cohort effects to be modeled (based on Frater et al. 2024). All analyses are done using the package mgcv in R and visualized using ggplot2.
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    Minnesota lake ice phenology
    (2024-06-04) Walsh, Jake R; Vitense, Kelsey; Rounds, Christopher I; Peter, Boulay; Blumenfeld, Kenneth; Hansen, Gretchen JA; round060@umn.edu; Rounds, Christopher I; University of Minnesota Fisheries Systems Ecology Lab
    This dataset contains ice in, ice out and ice duration data for Minnesota lakes that have been collated by the Minnesota Department of Natural Resources State Climatology Office. Lake ice has been recorded by lake associations, community members and scientists throughout Minnesota. The definition of lake ice in and out can vary from lake to lake but observers generally use consistent criteria for determining the day ice formation occurs or ice melts for a lake. For more information see the Minnesota DNR lake ice in (https://www.dnr.state.mn.us/ice_in/index.html) and ice out (https://www.dnr.state.mn.us/ice_out/index.html) websites.
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    Seasonal influence on detection probabilities for multiple aquatic invasive species using environmental DNA
    (2023-12-14) Rounds, Christopher; Arnold, Todd W; Chun, Chan Lan; Dumke, Josh; Totsch, Anna; Keppers, Adelle; Edbald, Katarina; García, Samantha M; Larson, Eric R; Nelson, Jenna KR; Hansen, Gretchen JA; round060@umn.edu; Rounds, Christopher; University of Minnesota Fisheries Systems Ecology Lab
    Aquatic invasive species (AIS) are a threat to freshwater ecosystems. Documenting AIS prevalence is critical to effective management and early detection. However, conventional monitoring for AIS is time and resource intensive and is rarely applied at the resolution and scale required for effective management. Monitoring using environmental DNA (eDNA) of AIS has the potential to enable surveillance at a fraction of the cost of conventional methods, but key questions remain related to how eDNA detection probability varies among environments, seasons, and multiple species with different life histories. To quantify spatiotemporal variation in the detection probability of AIS using eDNA sampling, we surveyed 20 lakes with known populations of four aquatic invasive species: Common Carp (Cyprinus carpio), Rusty Crayfish (Faxonius rusticus), Spiny Waterflea (Bythotrephes longimanus), and Zebra Mussels (Dreissena polymorpha). We collected water samples at 10 locations per lake, five times throughout the open water season. Quantitative PCR was used with species-specific assays to determine the presence of species DNA in water samples. Using Bayesian occupancy models, we quantified the effects of lake and site characteristics and sampling season on eDNA detection probability. These results provide critical information for decision makers interested in using eDNA as a multispecies monitoring tool and highlight the importance of sampling when species are in DNA releasing life history stages.