When Introduced equals invasive: Normative use of ?invasive? with ascidians

PATRICIO JAVIER PEREYRA; OCAMPO REINALDO, MATÍAS

Puerto Madryn

Congreso; Xth International Conference of Marine Bioinvasions; 2018

CENPAT

When Introduced equals invasive: Normative use of ?invasive? with ascidiansSince early 2000, there was ample debate on what is and how to define an invasive species. With several definitions coexisting and being used indistinctly, there was highlighted the possible use of the ?invasive? in a normative way, meaning that instead of describing an ecological behavior related with invasiveness (i.e. spread, effects), the species are labelled as invasive for other reasons (e.g. habit, citation practices). To test this hypothesis we have used as working examples introduced ascidians worldwide. We also describe the type of research performed with introduced ascidians, with focus in all ascidians vs. those described in the literature as model species, to synthetize the research made ascidians so far, and identified possible research gaps. A specific search in Web of Science was performed and articles suitable for analysis were selected. Each article was clasified according to the type of environment, species under study, type of effects and spread that ascidians are linked to. Most of the 184 articles analysed did not consider any type of dispersal or effects as study subject (82 and 71%, respectively). Most research was conducted in laboratory conditions (41%) or man-made environments (32%) or indicating few escapes to natural environments. Almost half of the articles (47%) where made with the six model ascidians. Those results indicate that the normative use is widely used regarding introduced ascidians. Spread and Effects, necessary conditions to consider a species as invasive, are notoriously understudied. Most research was not conducted in natural environments and over few species, weakening the perception of introduced ascidians as a conservation problem. This distinction allows us to discuss two separate aspects of the same phenomena: are some species intrinsically problematic for conservation (i.e. invasive) or is the movement of non-native species (i.e. biological invasion) the conservation problem?