Invasive Species: Will Europe At Last Unite To Combat Thousands Of Alien Invaders? (Apr 3, 2009) ScienceDaily. Recent evidence that Europe may be home to 11,000 alien species has spurred the European Commission to release its first ever Communication on invasive species. The Communication, which is currently open for consultation, proposes the development of a European Strategy on Invasive Species. It outlines three potential ways forward, each representing a different level of legislative cost and complexity.