Phenology data for the invasive macroalga Nitellopsis obtusa (starry stonewort) in Minnesota, USA, 2017 - 2018

Understanding the phenology of aquatic invasive plants is critical for evaluating and predicting their ecological impacts and timing control efforts. Despite its 45-year invasion history in North America, relatively little is known about the phenology of the invasive macroalga Nitellopsis obtusa (starry stonewort). We tracked N. obtusa phenology from 2017-2018 in two Minnesota (USA) lakes representing northern and southern clusters of N. obtusa invasion in Minnesota. We measured N. obtusa biomass and counted bulbils (asexual reproductive structures) throughout the growing season and in winter, under ice. These data are provided and documented here.