Plant invasion in undisturbed ecosystems: the triggering atrributes approach

GURVICH, DE; TECCO, PA; DÍAZ, S

JOURNAL OF VEGETATION SCIENCE

Opulus Press

Lugar: Uppsala; Año: 2005 vol. 16 p. 723 - 728

1100-9233

The invasion of a target community by a non-indigenous  plant species includes the stages of arrival, establishment and  spread, which tend to depend on different characteristics of the  invasive species and its context. While the mechanisms behind  the invasion of highly disturbed ecosystems are well  known, our understanding of the invasion process in undisturbed  or weakly disturbed ecosystems is much more limited.  Here we propose that, once a non-indigenous species has  arrived to a new ecosystem and become established, the likelihood  that it spreads, and thus becomes invasive, may depend  on just one or very few characteristics, called ‘triggering  attributes’ (TA). We propose that a TA is a vegetative or  regenerative attribute discontinuously distributed in comparison  to the resident community. This attribute allows the species  to benefit from a resource that is permanently or temporarily  unused by the resident community. We present an original  study case and examples from the literature to illustrate our  approach, and we also propose some ways to test it in different  ecosystems.  A considerable amount of research has been devoted  to understanding and predicting plant invasions (e.g.  Rejmànek & Richardson 1996; Kolar & Lodge 2001;  Shea & Chesson 2002). Several approaches have been  developed, including the search for a universal invasive  plant syndrome (Rejmànek & Richardson 1996; Kolar  & Lodge 2001), the release from natural enemies (Maron  & Vilà 2001; Keane & Crawley 2002), and the diversity  of the target community (see Levin & D’Antonio 1999;  Stohlgren et al. 1999 for discussion). All of them have  found only moderate success, particularly in understanding  the invasion of undisturbed or weakly disturbed  ecosystems (Godfree et al. 2004). In particular, a  set of characteristics that consistently distinguish nonindigenous  invasive species from indigenous invasive  species has not been identified so far (Noble 1989;