Submitted to: New Phytologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 1, 2010
Publication Date: August 1, 2010
Citation: Reinhart, K.O. 2010. The Role of Facilitative Interactions in Tree Invasions. New Phytologist. 187:559-562. Interpretive Summary: Short paper provides a commentary on the importance of facilitative interactions in plant invasions and more specifically woody tree invasion. • Current state- Although many experts believe that competitive interactions predominate there is increasing evidence that facilitative interactions are important in structuring plant communities and plant invasions. • Specific examples- Invasive woody trees often rely on direct and indirect facilitative effects for their establishment and survival. • Future studies concerning invasive species should couple associational patterns with more mechanistic and experimental approaches to uncover the processes driving invasion and impacts. Determining the relevance of knowledge among invasive species is necessary for advancing the field and requires conducting studies in various systems to determine what knowledge is transferable or context specific.
Technical Abstract: Many Ecologists studying the invasion biology of exotic plants have adopted the Gleasonian view that plant communities are primarily structured by competitive individualistic interactions and interdependent interactions (i.e. facilitation) are absent or limited (e.g. Bruno et al., 2005). However, some have speculated that facilitative interactions affect plant invasions (reviewed in Simberloff & Von Holle, 1999). For example, some invasive grasses increase the prevalence of fires which negatively affect resident species and indirectly facilitates additional invasion (D'Antonio & Vitousek, 1992). A literature survey revealed competitive interactions may be overemphasized relative to their actual occurrence in nature compared to facilitative interactions; however, this conclusion was based primarily on associational patterns since the majority of invasion biology studies are descriptive and nonexperimental (Bruno et al., 2005). It was relatively clear though that many more studies have been conducted that tested for competitive than facilitative effects (Bruno et al., 2005). Rigorous field experiments are necessary to characterize the individual direct and indirect interactions related to the invasion process, yet relatively few such studies exist (Simberloff, 2004; Bruno et al., 2005). A clever and insightful study by Saccone and colleagues (2010) addresses this concern with manipulative experiments that help elucidate the effects of direct and indirect interactions on the invasion process occurring in a European floodplain.