Chironomid communities of the upper St. Croix River, Wisconsin, were sampled for pupal exuviae at four locations monthly from April to October, 2007. Species richness was very high, with 252 species from 73 genera, dominated by the subfamilies Chironominae and OrthocladIInae. Most studies of lotic systems find fewer than 150 chironomid taxa, and often less than 100. The high richness may be due to regional conditions that support diverse aquatic communities, such as thermal regime, typical landscape patterns such as elevated mid-order stream diversity or increased β-diversity in headwaters, or the collection method which can detect species from adjacent habitats. There were 35 species that are atypical of lotic systems and some may have occupied microhabitats or adjacent habitat that more closely matches their preferences. Twenty-one species, mostly in OrthocladIInae, had range expansions into the western Great Lakes region or appear to be previously undescribed for the Nearctic. Sixty morphotypes, dominated by 41 Chironominae, did not fit any published exuviae descriptions.
|Original language||English (US)|
|Number of pages||32|
|Journal||Transactions of the American Entomological Society|
|State||Published - Dec 1 2019|
Bibliographical noteFunding Information:
An excellent review and conversation with Bohdan Bilyj resulted in important and valuable improvements to the manuscript, including numerous life-stage associations. Thanks also to Rick Damstra, Byron Karns and David VanderMeulen for additional comments. Initial support for this research was provided through a grant from the National Park Service to LCF. Additional support was provided by a grant from the Minnesota Agricultural Experiment Station, MAES Project # 17-031, also to LCF. Permission for field work and sample retention was provided by the St. Croix Falls, WI office of the St. Croix National Scenic Riverway. Research staff of the Chironomidae Research Group within the Department of Entomology at the University of Minnesota participated in sample collection, sorting, slide mounting and labeling of specimens, and their diligent efforts are appreciated and valued. Mr. Byron Karns, Ranger and Natural Resources Manager of the National Scenic Riverway, provided substantial assistance and guidance in the planning and execution of this project, both in terms of involvement in site selection and field work. His assistance was essential for the successful completion of this report. Additional clerical and administrative support was provided by the Department of Entomology, College of Foods, Agricultural and Natural Resources Sciences at the University of Minnesota. Interpretation of these data reflect the views of the authors and do not represent those of the U.S. National Park Service.
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- Saint Croix River