Biological attributes discriminating invasive from native European stream macroinvertebrates

Rising economic and ecological costs caused by invasive organisms revived research on biological attributes associated with invasiveness, focussing on the question: do invasive taxa have biological attributes favouring (1) propagule pressure; (2) dispersal; and (3) establishment and population growth? Using a literature-derived database on 312 stream macroinvertebrate genera occurring at 527 least human-impacted European sites, we quantitatively examined this question. Compared with native genera, genera with invasive invertebrate species (1) tended to reproduce more frequently and to have higher abundances (i.e. higher propagule pressure); (2) had no particular resistance stages to survive during dispersal; and (3) had significantly more ovoviviparity (enabling colonization by a single individual that typically releases viable offspring), larger size and longer life (providing resistance against mortality), food and feeding habits exploiting food resources in streams more effectively, and tended to be more dominant in their communities (all favouring establishment and population growth). Repeating these analyses excluding “native” flying insects (i.e. genera that presumably invaded from glacial refuges unnoticed by biologists), fewer biological attributes were significantly associated with invasiveness. For both data sets (all genera or insects excluded), their affinity to few biological traits (e.g. ovoviviparity, gill respiration) assigned the same 13 of the 19 invasive genera to the top 19 ranks on a gradient of potential invasiveness, together with native genera that risk to become invasive (e.g. Pisidium, Unio), but also with one endangered native genus (Margaritifera). Overall, our data support the idea that invasiveness can be predicted using biological attributes.