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The canary in the coal mine

A variety of species help scientists measure environmental impacts

algal bloom

"We want to live near aquatic resources without overly harming them. That’s sustainability," said NRRI Aquatic Scientist Valerie Brady. "And if we want to know how well we’re taking care of these resources, one way is to ask the critters how they are doing."

Those "critters" would be the bugs, birds, frogs, and fish that live in or near the water, and the plants that they rely on. NRRI turns to these flora and fauna as bioindicators of the condition of the near-shore regions of the Great Lakes. Coastal sampling done in the early 2000s allows the scientists to monitor changes over time. NRRI also uses bioindicators to monitor water quality in northland streams.

"Remarkably, the Great Lakes’ coastal areas haven’t been well-monitored in the past, and those are the areas where we interact most with the water... where we fish and play and swim," said Brady. "And 75 percent of fish use coastal wetlands at some time during their lives. Coastal areas are extremely important ecosystems."

NRRI’s crew of 24 spent the summer traveling from the north shore of Lake Superior to the far eastern end of Lake Ontario. They collected water and sediment samples, noted aquatic communities, and updated information on invasions by non-native species. The northern Minnesota crews also saw things they don’t normally encounter.

"Further east we were seeing shores with zebra mussel shells piled high and green blobs of decaying algae along the shore," said Brady. "The shells are sharp and it really smells bad. Nothing we’ve seen on Lake Superior looks like that, and we want to do what we can so it never does."

With some 1.7 million documented species on Earth, it’s important to understand which species are most effective as a bioindicators. Birds, for example, are especially useful because they live in every environment — from forests to grasslands to cities — and they’re easy to count, according to NRRI Ornithologist Jerry Niemi.

"We can easily monitor their population trends and then tie that to specific habitats," Niemi explained. "And habitat loss is one of the major reasons for population decline. That’s well-known."

NRRI scientists have built up a rich understanding of the biota of the freshwater resources of the Great Lakes. Invasive plants and fish tend to speed up the degradation process by reducing the biodiversity of an ecosystem. When they take over, the habitat changes along with the life it can sustain.

"With bugs we sometimes have to look at the extremes — the most sensitive creatures or the most tolerant," Brady explained. "The others can be harder to interpret. We call them the ‘muddle in the middle.’"

NRRI’s Great Lakes Environmental Indicators II and Great Lakes Coastal Wetland Monitoring projects are funded by the Environmental Protection Agency under the Great Lakes Restoration Initiative.