Browsing by Author "Hembre, Kaitlyn"

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    Data and R-code for "Aquatic Macrophyte and Water Quality Response to Aluminum Sulfate Treatments"
    (2025-03-05) Hembre, Kaitlyn; Newman, Raymond M; Bajcz, Alex W; Berg, Matt; James, William; newma004@umn.edu; Newman, Raymond; Minnesota Aquatic Invasive Species Research Center (MAISRC); water
    This study examines data from 6 lakes in Minnesota and 2 in Wisconsin to assess the response of aquatic plants and water quality to aluminum sulfate (alum) treatments. The dataset spans from 2011 to 2023 and includes measurements of total epilimnetic phosphorus, Secchi depths, and the frequency of native and invasive macrophyte species. Data were collected directly by project personnel but we also include data provided by project collaborators that were used in the formal analysis. Additional data collected by project personnel, including all point intercept aquatic plant data, temperature, light and dissolved oxygen profiles, and additional water chemistry data are included to facilitate further analysis in the future. Results indicate a marked reduction in total epilimnetic phosphorus levels and improved water clarity (Secchi) after alum treatment, with notable increases in native macrophyte occurrence. Invasive species such as curly-leaf pondweed decreased after alum treat, while Eurasian watermilfoil exhibited variable responses. This comprehensive dataset highlights the effectiveness of alum treatments in enhancing water quality and supporting macrophyte health, with considerations for ongoing invasive species management.
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    The response of native and invasive aquatic macrophytes to water quality conditions after aluminum sulfate treatments
    (2024-09) Hembre, Kaitlyn
    Aluminum sulfate (alum) treatments are a common method to reduce internal phosphorus loading, which improves water clarity and potentially enhances macrophyte growth. Despite the increasing use of alum to improve lake water quality, few studies directly examine macrophyte responses to alum treatments. We investigated the effects of alum treatments on water quality and aquatic macrophytes in five Minnesota lakes and two Wisconsin lakes in the USA. These lakes each had several years of pre- and post-alum treatment data for water quality and macrophytes, spanning 2011 to 2023. We assessed, for pre-, during-, and post-alum-treatment differences, for epilimnetic total phosphorus, Secchi depth, and total, native, and invasive plant frequency of occurrence. Using gamma mixed-effects regression models, we found that total epilimnetic phosphorus decreased and Secchi depth increased significantly after alum treatments. There was a significant increase in the frequency of occurrence of both total and native macrophytes following alum treatment and the subsequent increase in clarity. Invasive macrophyte species responses were variable, with curly-leaf pondweed decreasing and Eurasian watermilfoil exhibiting mixed outcomes after alum treatment. Planning for aquatic plant response should be part of alum treatment planning, and integrated management strategies that combine nutrient reduction with targeted invasive species control are needed to sustain ecological balance.