Less than 20,000 years ago, as the earth’s climate warmed and the last glacial continental ice sheet retreated, a system of interconnecting bodies of water began to form – a system we now know as the Laurentian Great Lakes. The Great Lakes comprise five large lakes, one small lake, four connecting channels, and a seaway that spans over 95,000 square miles (245,759 square km), and are now one of the world’s most critical natural resources. The Laurentia Bioregion is a land of waters. The unparalleled natural beauty of the Great Lakes inspires a sense of wonder and possibility. They are one of the world’s most significant water resources and the most extensive freshwater system on Earth. The Great Lakes — Superior, Michigan, Huron, Erie, and Ontario — represent thousands of years of history and continue to play an essential role in North America’s physical and cultural heritage. They are critical to the social and economic vitality of the entire North American continent.
The Great Lakes watershed, or Great Lakes basin, is defined by watersheds that drain into the Great Lakes. A watershed is an area of land where all the water that falls on it drains into the same outlet — for example, a stream, river, or lake. For this reason, a watershed is also called a drainage basin or catchment. A watershed comprises surface water (from lakes, streams, wetlands, and reservoirs) and all underlying groundwater. As water continues to move downward, streams and rivers may join with larger lakes and, eventually, the ocean. Great Lakes Guide combines the watersheds of the five Great Lakes, the Ottawa River, and the St. Lawrence River to bring you the full Great Lakes basin. The entire basin covers about 240,000 km² (94,000 square miles). There are 31,407 Great Lakes islands. They range in size from a small boulder to over 100,000 acres. In comparison, the Caribbean Islands consist of only about 7,000 islands. The Great Lakes basin is home to approx. Forty million people, nestled among two countries, two provinces, eight states, and 64 First Nations So what is so special about these Great Lakes Islands? Great Lakes Islands are the most extensive freshwater and inland system in the world, with biodiversity that is of global significance. The Great Lakes region is unique: It has one of the planet’s wealthiest and most ecologically diverse ecosystems. It encompasses forest, wetland, and grassland habitats and is home to over 4,000 species of plants, fish, and wildlife.
This ecosystem boasts some of the world’s most unique and diverse habitats — from rocky peninsulas and towering cliffs to vast marshlands and immense dunes. The Great Lakes Islands face numerous threats. Many have recreational, commercial, and residential use. Their popularity has ironically been the prime cause of the unintentional destruction of natural plant and animal communities. Native plant and animal communities on and around islands are vulnerable to invasion by non-native species (purple loosestrife, zebra, and quagga mussels). Other threats include sewage disposal, toxic contamination through heavy metals and pesticides, runoff from agriculture, urbanization, and air pollution. Stresses also include habitat loss, fragmentation, and climate change. Despite their large size, the Great Lakes are highly vulnerable.
Each year, only about 1% of the water in the lakes leaves the basin via the St. Lawrence River. The Great Lakes are essentially closed because water exits the system so slowly. Until European settlement, the Great Lakes ecosystem was also considered “ecologically naïve,” meaning that historically, its vulnerable animal and plant species were isolated. They are left uniquely exposed to pollution, invasive species, and habitat degradation.Past and present neglect of the system — unsustainable use, discharging of harmful chemicals, and climate change — have led to severe consequences for native species and the health of the Great Lakes. The four biggest ongoing issues facing the Great Lakes are habitat destruction, sewage pollution, river damming and diversion, and land-use runoff. The goal of the Regenerate the Great lakes is simple. To regenerate this area to be able to swim, touch and drink the waters that flow through this system, for both the human populations, and nonhuman that surround it for generations to come.