How is the Wildlife Doing?

Like fish populations, wildlife populations on land and in the air around the Great Lakes basin are subject to severe external pressure such as pollution and habitat loss. Controls on pollutants have enabled the bald eagle to make a comeback, but the little marsh wren is declining, along with its wetland habitat.

What is happening?

The health of any top predator, particularly a long-lived one, reveals a lot about the state of the entire ecosystem in which we all live. The bald eagle sits high up on the Great Lakes food chain, so it is a good indicator of environmental quality.

Not too long ago, spotting one of these big birds, especially in the southern Great Lakes, was a rarity. As farmers cleared the land of large trees, habitat for eagles disappeared. These magnificent birds were also hunted as “vermin” and their numbers dropped dramatically. Finally, the eagle’s ability to reproduce was impaired by the persistent bioaccumulative chemicals found in the fish and wildlife that were staples of its diet.

Today, however, this majestic bird, with its distinctive white head and brown-feathered body, can once again be seen soaring high overhead or perched in a tall tree. But the eagle is not totally out of danger. While more eagles inhabit the area now than did a few years ago, they still carry elevated levels of some contaminants, such as PCBs, DDE (a residue of the pesticide DDT), and the heavy metals lead and mercury. Although DDT was banned in North America in the 1970s, it persists in the environment, and PCBs are still used in some old electrical equipment, which periodically leaks. Lead is used in hunting and fishing equipment, and mercury is released into the environment from a number of sources.

The double-crested cormorant, a fish-eating bird high on the food chain, also experienced a population surge around the Great Lakes, mainly because of lower pollution levels and more available habitat. The phenomenal increase in the cormorant population provides an important lesson about what can happen once we begin to rehabilitate an ecosystem. Decades ago, cormorants could not reproduce because of the effects on them of toxic chemicals, but, as pollution levels fell, the cormorant population boomed. In some areas, these birds have become so numerous that they have displaced other waterbirds, and cormorant droppings have destroyed some vegetation. Wildlife managers are now trying to control some cormorant populations to limit their impact on the environment. Habitat change is a major factor in the survival of species. In some areas around the Great Lakes, wetlands and forests are increasing where farms are abandoned and reclaimed by nature or landowners set aside land for wildlife. In other parts of the basin, habitat is decreasing as industrial, agricultural, and residential expansion overtakes woods, pastures, and wetlands.

While the species just mentioned are on the rebound, populations of other birds, such as the black tern, American coot, and marsh wren, are declining, apparently due to loss of the healthy wetlands that they need. Some species of frogs and toads are also in decline. In parts of the Great Lakes, snapping turtles are contaminated with chemicals, which negatively affect the reproduction of this species.

Figure 8: Average number of occupied nesting areas by lake.	Figure 9: The bald eagle is a not just a powerful cultural symbol. Its recovery around the Great Lakes is a measure of our ability to repair environmental damage. The graph shows that bald eagles now are nesting extensively throughout the Great Lakes. The map shows bald eagle nesting areas along Great Lakes shorelines in 2000

What is being done?

The bans and controls on pollutants over the past three decades have improved the health of wildlife. Generally, wildlife populations, except in highly polluted areas, are reproducing normally.

Habitat has been increasing. Governments and non-governmental organizations, as well as a number of businesses and private industry, have been creating parks and nature reserves. Around the Great Lakes, the amount of land protected by land trusts and conservancies has been growing steadily and is an important sign of citizen and community stewardship. Today, about one-fifth of the remaining Lake Ontario wetlands is protected. In the Lake Michigan watershed, the gray wolf, bald eagle, Kirtland’s warbler, and Piping Plover have benefited from habitat protection and restoration.

In an effort to help nature recover, governments have committed to protection and recovery plans for endangered species. Such plans include habitat protection and reintroduction of species.