1. St. Croix Watershed Research Station, Science Museum of Minnesota, Marine on St. Croix, MN, USA
2. Andresen Consulting LLC, Ypsilanti, MI, USA
3. National Park Service, Great Lakes Inventory & Monitoring Network, Ashland, WI, USA
4. Earth and Environmental Systems, Indiana State University, Terre Haute, IN, USA
5. Research Department, Meise Botanic Garden, Meise, Belgium
6. Department of Biology – ECOBE, University of Antwerp, Antwerpen, Belgium