Seasonal Changes of Benthic Macroinvertebrate Functional Feeding Group Biomass Within Forest and Meadow Habitats of a First-order Michigan (USA) Stream

Little is known about seasonal changes in stream benthic macroinvertebrate assemblages. We determined the ash-free dry mass of macroinvertebrates within a forested and a meadow reach of Fairbanks Creek in northern Lower Michigan throughout all seasons of 2018 and 2019. The macroinvertebrate assemblage of the forested reach was dominated by invertebrates in the shredder functional feeding group (FFG), whereas the meadow reach was composed primarily of scrapers and filtering collectors. Regardless of reach, the biomass of all FFGs was low during the winter and early spring, peaked in May or June, and gradually declined throughout the summer and fall. General trends in biomass were the same for both years of the study, although 2018 had overall higher biomass despite being a slightly cooler year.