Tracking the Pulse of Old Man River
BY MARK STEINGRAEBER, LA CROSSE FWCO
events has increased steadily since 2012.
The Upper Mississippi River National Wildlife and Fish Refuge (NWFR) was established in 1924 as a refuge for fish, wildlife, and plants, and a breeding place for migratory birds. The refuge encompasses one of the largest blocks of floodplain habitat in the lower 48 states. Bordered by steep wooded bluffs that rise above the river valley, the Mississippi River corridor and refuge offer scenic beauty and productive fish and wildlife habitat unmatched in the heart of America. Covering a total of more than 240,000 acres in Minnesota, Wisconsin, Iowa, and Illinois, the refuge extends 261 river miles and is designated as both a Wetland of International Importance (Ramsar) and a Globally Important Bird Area.
Winona (MN) on July 8, 1966. Credit: Calvin Fremling
Among all the creatures that inhabit the refuge, the brief, synchronous, annual emergence of mayflies from the river in mid-summer is one of the most spectacular phenomena to occur here. Large emergence events can number in the millions - enough to be picked up by weather radar and attract visitors from around the globe eager to experience it. As larvae, these aquatic insects cannot tolerate low levels of dissolved oxygen; thus, their annual appearance is widely regarded is an indicator of good water quality conditions during the past year. As avid anglers know, mayflies are an important food source for fish, not only during the summer emergence, but throughout the year.
As a means of monitoring the relative health of the river over a broad spatial scale and to learn more about the basic biology of this iconic insect, the La Crosse Fish and Wildlife Conservation Office (FWCO) has been monitoring the annual “pulse” of mayflies that emerge from Old Man River in the Upper Mississippi River NWFR (and beyond) since 2012 with the help of a growing volunteer network of citizen scientists.
As it happens, this effort closely parallels the National Wildlife Refuge System (NWRS) Inventory and Monitoring Initiative to collect and analyze data on seasonal changes in key plants and animals from year to year (e.g., the emergence of insects), especially their timing and its relationship with prevailing weather and climate patterns. Technical support for this NWRS endeavor is provided by the USA-National Phenology Network (NPN), an organization that brings together citizen scientists, government agencies, non-profit groups, educators, and students of all ages to monitor the impacts of climate change on plants and animals in the United States. This initiative is designed to support refuge operations by providing standardized methods and protocols for widespread data collection to help make better informed management decisions and facilitate implementation of on-the-ground actions.
Thus in 2015, La Crosse FWCO and Upper Mississippi River NWFR staff successfully petitioned the USA-NPN to have two species of burrowing mayflies (Hexagenia bilineata and H. limbata) added to Nature’s Notebook, the organization’s national online program where professional scientists and amateur naturalists regularly record observations of plants and animals to generate long-term data sets used for scientific discovery and decision-making. The value of this on-line application was publically recognized at the Forum on Federal Crowdsourcing and Citizen Science Toolkit held recently at the White House.
A total of 57 citizen scientists observed and reported 174 discrete mayfly emergence events in the UMR this year in a reach of river spanning more than 350 miles from St. Paul, Minnesota to Muscatine, Iowa. Some of these timely reports were also used in research and management efforts to restore mayfly populations in portions of Lake Michigan.
Although only a small fraction of Americans are formally trained as “scientists”, that doesn’t mean that only a small fraction of Americans can participate in scientific discovery and innovation. Citizen science is one approach to educate, engage, and empower the public to apply their curiosity and talents to a wide range of real-world problems. At the Upper Mississippi River NWFR, plans are to promote and expand the use of Nature’s Notebook to increase citizen science participation in monitoring populations of other fauna (e.g., bald eagles, monarch butterflies) and flora (e.g., milkweed) on the refuge. The USA-NPN is also planning to increase participation in the Mayfly Watch program in 2016 with a special campaign highlighting this effort. For more information, visit: https://www.usanpn.org/fws/mayflywatch.