25. Introduction of Non-indigenous Species

With the commencement of anthropogenic transcontinental movements followed by a continually increasing global traffic and intentional transfer of organisms, a diverse array of human-mediated pathways appeared responsible for transporting numerous marine species between different eco-regions. World-wide shipping increased dramatically over the last centuries emerging now as the most important vector for un-intentional artificial range-extensions of marine organisms thereby causing a steady raise in the introduction rate of non-indigenous species to most coastal regions of all oceans. Such neobiota pose a high functional risk if they develop stable populations and turn invasive with often detrimental effects on diversity and foodwebs of the indigenous ecosystems, even imposing high social-economic damage. Science is advancing in the attempt to understand the mechanisms of introduction and invasiveness which are crucial for further management approaches on national as well as international levels. Non-indigenous species have to be understood as a major pollution problem connected to every-day activities on all levels of society. Since the establishment of invasive species is nearly irreversible and attempts to eradicate populations of invasive organisms are mostly futile, a stringent prevention management on a global scale has to be anticipated.