Data supporting: Evaluation of a decade of management of a North American aquatic invasive species (Nitellopsis obtusa) highlights scale-dependent effectiveness and monitoring gaps

Abstract

Nitellopsis obtusa (starry stonewort) is an invasive macroalga subject to substantial control efforts in the Midwestern United States; however, there has not been systematic evaluation of treatment effectiveness. We synthesized management approaches and outcomes using monitoring performed over a decade-long period across 38 lakes in Indiana, Wisconsin, and Minnesota. We compiled all available point-intercept (PI) survey data from lakes where N. obtusa was known to occur since the year the species was first discovered in each state (Indiana, 2008; Wisconsin, 2014; Minnesota, 2015) until 2018 (Indiana) and 2019 (Wisconsin and Minnesota). These data comprised raw survey and summary data from whole-lake PI surveys, as well as targeted sub-PI surveys within managed areas. We compiled all available information on N. obtusa management for the time periods encompassing the survey data. Management data were collected from: 1) pesticide application records (PARs; Minnesota), 2) chemical treatment and mechanical harvesting records (Wisconsin), 3) aquatic vegetation management plans (AVMPs; Indiana), and 4) direct knowledge of known management events (all states). We compiled as much information as possible for each management action on each lake. For hand pulling, we additionally compiled all available data on the biomass of N. obtusa removed during each event; we included all such data through 2022.