Approximately 12,000 Common Loons, over half the population in the continental U.S., breed in Minnesota. U of M researchers lead the world in studies of impaired loon behavior and reproduction due to elevated levels of mercury. Common Loons are identified as a species at risk to mercury because nearly 40% of their habitat range lies in regions with high mercury deposition from acid rain, and because they are long-lived birds that accumulate mercury from the fish they eat.

Fluctuations in moose and wolf population have been documented in studies on public lands from Alaska to Isle Royale in Lake Superior for more than half a century.

Isle Royale, isolated since the glaciers retreated, is a grand-scale ecological laboratory. A fire in 1936 burned 26,000 acres or about one-fifth of the island. The regrowth produced an abundant food supply and the moose herd grew from about 200 to 800 in 12 years. It is estimated that the first wolves arrived on the island about that time.

The earliest measurements of moose impact on the boreal forests of Isle Royale began in the ’40s, with a joint U of M forestry and U.S. Fish and Wildlife research project. Moose exclosures—four unbrowsed plots protected by a 10-foot-high fence—were built at Isle Royale between 1948 and 1950 and are located in different forest types. They remain in place today and have served as models for others. University wildlife researchers have also discovered that sodium from aquatic vegetation—primarily in beaver ponds—is an essential nutrient for moose.

The Minnesota River is one of America’s 20 most endangered waterways. Most of the watershed is highly agricultural, with a significant urban influence in the lowest reaches. The University has long-term and widespread research involvement in the basin. In multiple projects, with funding from the National Science Foundation, Environmental Protection Agency, U.S. Geological Survey, and the Legislative Commission on Minnesota Resources, University scientists developed a watershed approach to study cumulative effects from the South Dakota border to the Gulf of Mexico. They analyze how the interaction of land-use, and management practices in the Minnesota River Basin will affect in-stream biological communities and export of sediment, nitrogen, and phosphorus to the Gulf.

One measure of lake or stream productivity is the number of fish living there and the size and health of those fish. Research in limnology—the scientific study of physical, chemical, meteorological, and biological conditions in fresh waters—began at the University in 1926 with “A Study of the Productiveness of Minnesota Lakes in Fish and Fish Food,” supported in part by the Ten Thousand Lakes Association. That three-year study initiated extensive work on fish populations. Examination of the impact of Red Lake’s Native American commercial fishing enterprise began in 1949 and tracked extreme population changes. Students assisting researchers learn many techniques to sample fish populations including electrofishing, trap netting, and gill netting—used later in jobs with natural resource agencies. This muskie was caught in a gill net and died; unfortunately a small percentage of fish die in the sampling process.

Minnesota is a unique place to study Habitat protection, the 1972 ban of DDT, and increased public awareness of the need to protect the species has helped Minnesota’s breeding population of bald eagles soar from a federally threatened species to more than 700 breeding pairs.

University of Minnesota researchers were there at the beginning contributing to the discovery that eagle nests in places with little human contact yield the most young. That research led to federal guidelines to deter human interference during the nesting season. Thirty years ago, a graduate student approached this nest—likely weighing over 1,000 pounds—to check for signs of a successful hatch.

A unique long-term study on a stream near Afton, from 1965 to 1986, investigated the health and productivity of all levels of aquatic life. Mother Nature cooperated with a spring flood early in the study, allowing researchers to track how the fish and food populations responded to a disrupted habitat. The study’s results led to increased understanding of 24-hour rhythms of the drifting aquatic insects and invertebrates, and to new methods to determine productivity in streams. Both findings are internationally recognized as groundbreaking.