How common are invasion-induced ecosystem impacts?

Abstract

It would be an exaggeration to argue that most invasions produce ecosystem impacts, and the term should be reserved for cases in which many species in an ecosystem are affected. However, certain facts suggest that true ecosystem impacts are more common than is normally assumed. First, the term ''ecosystem impact'' has often been reserved for cases in which the nutrient regime or nutrient cycling is affected, whereas physical structural and other changes in ecosystems ought to be included. Second, as with all ecology, very few systems and species have been studied relative to all those that exist, so it is likely that many ecosystem impacts remain to be detected. Third, there are many types of impacts, many are idiosyncratic, many are subtle, and many are indirect, so it is likely that many impacts have simply not been recognized even in studied systems. Finally, the frequency of the lag phenomenon in invasions implies that at least some existing nonnative species that are currently having little or no impact will eventually have much greater ones. These facts suggest that, even if it would be an overstatement to say that most invasions cause ecosystem impacts, it would not be more of an overstatement than the common assertion that very few introduced species have any significant impact.

Pour une autre représentation métaphorique des invasions biologiques

“…Les invasions biologiques ont en outre été érigées au rang des changements globaux, bien que leurs effets sur l'environnement, notamment sur les extinctions d'espèces, et leur lien causal dans les changements environnementaux observés demeurent encore vigoureusement débattus (Lövei, 1997 ;Vitousek et al, 1997 ;Gurevitch et Padilla, 2004 ;Didham et al, 2005 ;Davis et al, 2011 ;Simberloff, 2011). Dans un contexte où l'origine des nuisances imputées aux espèces invasives est parfois méconnue ou oubliée, le contrôle, voire l'éradication de ces espèces parfois érigées en parias et en boucs émissaires contribuent dès lors à expier la faute de l'Homme malmenant la Nature (Warren, 2005 ;Larson, 2010).…”

Impacts of biological invasions: what's what and the way forward

“…Some invasive consumers remove or add physical structures, altering erosion regimes and changing habitat suitability for other species [41]. Belowground, several invasive consumers also radically transform ecosystems (Table 1).…”

Surviving in the south: a recent incursion of the agile wallaby (Macropus agilis) in Tasmania

“…The primary factors that define the feasibility of eradication are the relatively small population size and confined distribution of M. agilis, as documented in this study. Eradication is likely to be the most economically and ecologically sensible solution in the long term (Simberloff 2011). We recommend that the existing population be eradicated before environmental conditions and population status change to favour a further expansion that would ultimately make the future task of control or eradication difficult.…”