Globalization pressure and habitat change: Pacific rocky shore crabs invade armored shorelines in the Atlantic Wadden Sea

Two invasive crab species from the Northwest Pacific, Hemigrapsus sanguineus and H. takanoi, have rapidly established themselves along armored shorelines of the Atlantic Wadden Sea, reaching densities exceeding 100 crabs per square meter within just 2-3 years. These invaders exhibit distinct microhabitat preferences, with H. sanguineus dominating exposed shores while H. takanoi thrives in sheltered areas and on mussel/oyster beds. A field experiment revealed that H. sanguineus displaces juvenile native shore crabs (Carcinus maenas) from boulder substrates, though this effect is largely confined to armored shorelines, with minimal impact on large C. maenas populations in soft-bottom habitats of the North Sea. This study highlights the rapid ecological disruption caused by invasive species and their selective pressure on native fauna, particularly in human-altered coastal environments.

Landschoff, J., Lackschewitz, D., Kesy, K., & Reise, K. (2013). Globalization pressure and habitat change: Pacific rocky shore crabs invade armored shorelines in the Atlantic Wadden Sea. Aquatic Invasions, 8(1), 77–87. https://doi.org/10.3391/ai.2013.8.1.09