Rivers and Lakes

Guarding Rivers and Lakes from Invasive Species

As our world becomes smaller and globalization becomes a way of life, stowaway species being transported in global commerce often end up in faraway places and unintentionally reap havoc on native ecosystems.

Often referred to as invasive, nuisance, exotic, or non-native species, these stowaways can appear benign -- even natural -- but in reality they are one of the greatest threats to biodiversity. They are also a threat to our economies. In the United States alone, aquatic invasives are estimated to cost more than $73 billion (USD) a year.

Aquatic invasive species sharply alter the ecosystems they invade by reducing or eliminating native species by altering food chains and water quality, directly preying on them, and competing with them for food and space.

Lakes and rivers are especially susceptible to this threat because of the very nature of water and its use for transporting goods and people around the world. The Nature Conservancy is addressing aquatic invasive species by providing science based solutions in two phases:

  • Stop the spread of invasive species through education, partnership and policy
  • Manage invasions and restore freshwater habitats

Today we are increasingly focused on preventing invasions before they occur. Prevention can save millions in future costs of control, human health impacts and fishing losses. While there are countless potential invaders, most invade through only a few key pathways. We focus on identifying and closing these pathways without impeding trade or travel.

Focus on the Great Lakes

North America is home to a massive body of fresh water -- the Great Lakes -- which hold 20 percent of the world’s fresh water and 95 percent of North America’s surface water. The St. Clair River Delta is the world’s largest freshwater river delta.

The 37 million people who live in the Great Lakes Basin depend on this freshwater resource for:

  • Food;
  • Water;
  • Jobs; and
  • Industry.

Aquatic invasive species are one of the principal ecological and economic threats to the Great Lakes. In recent years, an average of at least one new invader has been discovered in the Great Lakes each year. With many connections to shipping pathways, the Great Lakes are one of the major entryways for freshwater invaders into North America. Invasives that enter the Great Lakes can then spread across the continent through river systems such as the Mississippi.

The Nature Conservancy is working with researchers at the University of Notre Dame to find conservation solutions by looking at some of the ways species are introduced. The Conservancy and CAC are now working to determine which specific pathways have the highest risk of being entry points for invasive species. Some of this work includes developing models of recreational boater movements, as well as models to determine the riskiest global shipping routes for potentially harmful species introductions. A better understanding of pathways provides guidance on how to prioritize management and policy efforts.


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