New Report Counts, Categorizes & Ranks Great Lakes Islands

Scientists Say World’s Largest Collection of Freshwater Islands Globally Rare; Needs Conservation Action to Protect Threatened Species

TORONTO, ON, CANADA | August 20, 2010

With more than 32,000 islands in its waters, the Great Lakes contain the world’s largest collection of freshwater islands, but these islands are dynamic, undergoing many changes that threaten the islands’ flora and fauna, including climate change, habitat degradation, invasive species and some natural processes, according to a new report published by scientists from leading conservation organizations in the United States and Canada.

The report, titled “Islands of Life,” ranks and describes the biodiversity (biological diversity) and threats to priority islands found in the Great Lakes. These islands provide essential habitat for migratory and nesting birds as well as rare plants and animals like the piping plover and Pitcher’s thistle, found nowhere else on Earth.

“This information has never been collected and categorized before,” said Dr. Patrick Doran, director of science in Michigan and the Great Lakes for The Nature Conservancy. “From conducting research and then analyzing the report, we learned that islands ranked highest in biodiversity are often also subject to greater threats from human activity. This helps us and others decide and prioritize our conservation action.”

Dr. Doran said that he hopes others will read and learn from the report to make more informed decisions about conservation acquisitions, practices and other strategies aimed at protecting the most vulnerable habitats for rare and declining species in the Great Lakes.

“No matter what side of the lakes you live on, what we do on land and in the water affects the health of this critical freshwater system,” said Chris Maher, regional vice president for the Nature Conservancy of Canada. “Partnerships like this help share our science and leverage the information so that we are collectively working together to ensure the health of the lakes and the islands within them that provide critical habitat for wildlife.”

The Nature Conservancy collaborated with the Ontario Ministry of Natural Resources, Natural Heritage Information Centre, Nature Conservancy of Canada, Great Lakes Program, University of Minnesota, U.S. Fish & Wildlife Service, and Great Lakes Islands Project to create the report.

Biodiversity of the islands was measured by the number of species, plant communities, ecological systems, and ecosystem functions, along with shape complexity, geological diversity, shoreline diversity, size, and distinctiveness. An island with a high biodiversity score may provide habitat for specialized plants, animals and natural communities. According to the report, the top 10 islands based on highest total biodiversity scores are:

1. Manitoulin Island (South) Lake Huron Northern Coast
2. Manitoulin (North) South Coast North Channel
3. Pelee Island (Main) Western Lake Erie Islands
4. Walpole Island St. Clair River, Lake St. Clair and Detroit River
5. Point aux Pins Rondeau System
6. Drummond Island (Main) South Coast North Channel
7. Great LaCloche Island North Coast North Channel
8. Long Point Long Point, Turkey Point Systems and Northeast Coast
9. Drummond Island (Southcentral) Lake Huron Northern Coast
10. Squirrel Island and Cockburn Island (South) Lake Huron Northern Coast

Common threats to the islands include incompatible residential and cottage developments, tourism and recreation, marinas and resorts, increased road and building densities, increased access points for boats and other vehicles, incompatible agricultural practices and invasive species. According to the report, the top ten most threatened islands are:

1. Manitoulin Island (North) South Coast North Channel
2. St. Joseph Island (West) St. Mary’s River
3. Grosse Isle St. Clair and Detroit River
4. Grand Island (West) Welland Canal – Niagara River
5. Grand Island (East) Welland Canal – Niagara River
6. Manitoulin (South) Lake Huron Northern Coast
7. Kelleys Island Western Lake Erie Islands
8. Drummond Island (Main) South Coast North Channel
9. Wellesley, Sugar, South Bass, Harsens, Madeline Islands (Lake Ontario, Lake Erie, St. Marys River, Lake St. Clair)
10. Beaver Island, Wolfe Island (Lake Michigan, Lake Ontario)

The Nature Conservancy of Canada (NCC) is Canada's leading land conservation organization. Since 1962, NCC has helped to protect more than 2 million acres (8,100 square kilometres) of ecologically significant land nationwide. To see a full copy of the report, visit

Additional Online Component (Note: Works best with the latest version of Google Earth):
Islands of Life Google Earth Application - A Web-based Companion to the Islands of Life Report:

This application is developed for quick and effective communication, data-sharing, and analysis and rapid decision-making. This application enables audience to zoom in on any key island indentified in the report to make a quick assessment of the conservation value and other island features of the island, including biodiversity components and threats to that island’s biodiversity.

The Nature Conservancy is a global conservation organization dedicated to conserving the lands and waters on which all life depends. Guided by science, we create innovative, on-the-ground solutions to our world's toughest challenges so that nature and people can thrive together. We are tackling climate change, conserving lands, waters and oceans at unprecedented scale, and helping make cities more sustainable. Working in more than 65 countries, we use a collaborative approach that engages local communities, governments, the private sector, and other partners. To learn more, visit or follow @nature_press on Twitter.


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