Aquatic invasion patterns across the North Atlantic

Area of Science:

• Ecology
• Environmental Science
• Conservation Biology

Background:

• Biological invasions are a primary cause of global biodiversity loss and socioeconomic disruption.
• Aquatic ecosystems near urban centers are particularly vulnerable to alien species establishment due to diverse introduction pathways and biosecurity weaknesses.
• Understanding historical invasion dynamics is crucial for predicting future alien species impacts.

Purpose of the Study:

• To compare alien species composition, geographic origins, and overlap across three North Atlantic aquatic systems: Chesapeake Bay, Great Lakes-St. Lawrence River, and North and Baltic Seas.
• To identify similarities and differences in invasion patterns among these major trade hubs.
• To inform global biosecurity strategies for managing alien species.

Main Methods:

• Compiled and compared alien species lists for Chesapeake Bay, Great Lakes-St. Lawrence River, and North and Baltic Seas.
• Focused analysis on selected macroinvertebrate, algal, and fish taxa to ensure consistent taxonomic and biogeographic resolution.
• Analyzed the geographic origins and taxonomic groups of established alien species.

Main Results:

• A total of 326 alien species were identified across the three regions, with the North and Baltic Seas most affected (163 species).
• Common origins included Ponto-Caspian, Eurasian, Northwest Pacific, Northwest Atlantic, and North American.
• Despite shared origins, taxonomic composition and geographic success varied significantly among the recipient systems, with Ponto-Caspian species being particularly successful in European waters.

Conclusions:

• Most alien species (approximately 80%) were established in only one of the studied regions, indicating disparate invasion patterns.
• The findings underscore the potential for future alien species introductions from diverse sources and pathways.
• Effective biosecurity measures must consider a wide range of geographic origins and taxonomic groups to mitigate the translocation, arrival, and spread of alien species globally.