HIPPCO Threats to Biodiversity--Invasive Species

Invasive Species as a Threat to Biodiversity

The lesson covers the “I” in HIPPCO: invasive species. These are non-native species that enter an area and outcompete native species. They may thrive because they fit successfully into local ecological niches and lack the diseases, predators, or other natural controls that limit them in their original environments.

Examples in the Midwest

• Buckthorn: Common (European) and glossy buckthorn were brought from Europe for use as hedging plants. They have spread into forests, crowding out native plants and displacing native shrubs and small trees. Because local diseases and insects do not keep them in check, they often have to be removed by hand.
• Sea lampreys: These fish entered the Great Lakes region through cargo-ship ballast water discharged along the St. Lawrence Seaway. Native to the Adriatic and Mediterranean seas, they adapted from salt water to fresh water. They attach to other fish and suck their blood; the lesson notes their presence in Lake Superior.
• Zebra mussels: Also introduced through cargo-ship ballast water, zebra mussels arrived in the 1980s and spread through the Great Lakes and Mississippi drainage rivers. They filter algae from the water, which can harm ecosystems where algae provides cover for young fish. They also attach to native mussels and can kill them.

Key Lesson

Invasive species can disrupt ecosystems by taking resources or habitat from native species, preying on or harming them, and changing environmental conditions.

Speaker

Miss Longley — instructor presenting the lesson.