Biotic interactions and plant invasions

Abstract

Introduced plant populations lose interactions with enemies, mutualists and competitors from their native ranges, and gain interactions with new species, under new abiotic conditions. From a biogeographical perspective, differences in the assemblage of interacting species, as well as in abiotic conditions, may explain the demographic success of the introduced plant populations relative to conspecifics in their native range. Within invaded communities, the new interactions and conditions experienced by the invader may influence both its demographic success and its effects on native biodiversity. Here, we examine indirect effects involving enemies, mutualists and competitors of introduced plants, and effects of abiotic conditions on biotic interactions. We then synthesize ideas building on Darwin's idea that the kinds of new interactions gained by an introduced population will depend on its relatedness to native populations. This yields a heuristic framework to explain how biotic interactions and abiotic conditions influence invader success. We conclude that species introductions generally alter plantsÕ interactions with enemies, mutualists and competitors, and that there is increasing evidence that these altered interactions jointly influence the success of introduced populations.Ecology Letters (2006) 9: 726-740

Soil conditioning effects of Phragmites australis on native wetland plant seedling survival

“…PSF theory predicts that invasive plant species can engineer a competitive advantage over native plants through soil conditioning effects (Beckstead et al., 2010; Eppinga, Rietkerk, Dekker, & De Ruiter, 2006; Hierro & Callaway, 2003; Mangla & Callaway, 2007; Mitchell et al., 2006; Reinhart & Callaway, 2006; Saltonstall, 2003; Wolfe & Klironomos, 2005). Our results demonstrate that both EU and NA may amplify the abundance, or facilitate the colonization, of fungi that reduce survival of competing wetland plant species at the seedling stage.…”

“…Interactions between introduced plant species and the soils they colonize are increasingly being recognized for their central role in determining success and failure of plants to establish, grow, and become invasive (Hierro & Callaway, 2003; Inderjit & van der Putten, 2010; Mitchell et al., 2006; Reinhart & Callaway, 2006; Wolfe & Klironomos, 2005). Although all plants have species‐specific effects on soil they colonize (Bardgett & van der Putten, 2014; Berg & Smalla, 2009), invasive plants often appear to alter soils to their advantage, creating positive plant–soil feedback and promoting dominance (Berg & Smalla, 2009; Bever, 1994; Diez et al., 2010; Fitzsimons & Miller, 2010; Flory & Clay, 2013; Klironomos, 2002; Kowalchuk, Buma, De Boer, Klinkhamer, & van Veen, 2002; Peterman, Fergus, Turnbull, & Schmid, 2008; van der Putten et al., 2013; van Grunsven et al., 2007).…”

In a long-term experimental demography study, excluding ungulates reversed invader's explosive population growth rate and restored natives

“…for all stages) in invaded systems (2,14,17,32,33). Instead, herbivore-plant invader experiments typically report simple metrics of plant success (e.g., percent cover or counts of individuals) at a single time point.…”

“…According to ecological theory, the ability of the resident community to limit the success of invading exotics [biotic resistance (9,10)] will depend upon ecological context that includes the suite of local interactors (11)(12)(13)(14)(15). The abundance of herbivores and their local impacts (11,14,16) can play a prominent role in how fast plant populations grow or shrink and how much the relative abundance of plant species changes over time (5,15), including changes associated with plant invasions (11,(16)(17)(18)(19). Recently, increased browsing pressure by overabundant ungulate herbivores on native plant communities has been proposed as a fundamental cause of a shift from native to exotic plant domination in forests and rangelands worldwide (11,16,20).…”

Parent tree distance-dependent recruitment limitation of native and exotic invasive seedlings in urban forests

“…Additionally, the high invasive pressure of the studied urban forest stands, not only by exotic invasive trees but also by understory species (data not shown), suggests possible invasive meltdown, where introduced species facilitate the spread of new exotic species (Meltdown hypothesis; Simberloff 2006). Exotic species may alter soil communities potentially changing plant-soil feedback interactions of the native plant community (Mutualism disruption; Mitchell et al 2006;Toby Kiers et al 2010). Despite the high amount of pathogens present in the roots of the exotic invasive species R. cathartica compared with the other target species, R. cathartica is a successful invader of the sampled stand.…”