Briefcase Study of the Role of the Teacher in the Lls Linked Own or Intended Practice

The Effect of Invasive Species on Marine Biodiversity

Figure 1. Areas at risk to biological invasions due to ballast water transport, red indicated high risk while blue signifies low risk. From Drake & Lodge (2004)

There are problems throughout the world with invasive alien species that have been introduced through human activities and been left to thrive away from natural predators and parasites. Although the ones most known to the public are land invaders such as the grey squirrel (Sciurus carolinensis Gmelin) infestation of the UK or the European rabbit (Oryctolagus cuniculus Lin.) invasion of Australia there are also a myriad of species transported around the worlds oceans every day (Carlton, 1999). The method of such invasions is usually the uptake of ballast water that allows for the transport of any suitably small organism or any species with a planktonic dispersal phase but transport can also be accomplished via fouling on the hull of ocean going vessels, release of captive individuals or via the aquaculture industry (Carlton, 1999). Due to these facts areas subject to high volumes of commercial shipping are especially vulnerable to marine invasions (Drake & Lodge, 2004) ( [ Figure 1 ]).
This situation is not improved by mans influence on coastal areas, the building of coastal structures and input of pollutants into the marine environment provides new habitats where settlement rates of new invasive species can be increased (Baxa, Williamsona, Aguerob, Gonzalezb et al., 2003). Even taking this into account the proportion of relocated species that successfully establish is decidedly low; Williamson (1996) postulated that of all the species transported throughout the world only 0.1% were successful in establishing a stable population. The problem comes however when you consider the 10,000 species relocated every week by ballast water transport alone (Carlton, 1999), this would provide an estimate of 10 novel species that are able...