Phylogenetically Poor Plant Communities Receive More Alien Species, Which More Easily Coexist with Natives

Abstract

Alien species can be a major threat to ecological communities, but we do not know why some community types allow the entry of many more alien species than do others. Here, for the first time, we suggest that evolutionary diversity inherent to the constituent species of a community may determine its present receptiveness to alien species. Using recent large databases from observational studies, we find robust evidence that assemblage of plant community types from few phylogenetic lineages (in plots without aliens) corresponds to higher receptiveness to aliens. Establishment of aliens in phylogenetically poor communities corresponds to increased phylogenetic dispersion of recipient communities and to coexistence with rather than replacement of natives. This coexistence between natives and distantly related aliens in recipient communities of low phylogenetic dispersion may reflect patterns of trait assembly. In communities without aliens, low phylogenetic dispersion corresponds to increased dispersion of most traits, and establishment of aliens corresponds to increased trait concentration. We conclude that if quantified across the tree of life, high biodiversity correlates with decreasing receptiveness to aliens. Low phylogenetic biodiversity, in contrast, facilitates coexistence between natives and aliens even if they share similar trait states.

Do species differ in their ability to coexist with the dominant alien Lupinus polyphyllus? A comparison between two distinct invaded ranges and a native range

“…At the same time, the insular flora of New Zealand can be expected to be phylogenetically rather homogenous, originating from a few clades originally colonizing the islands. Such communities have been documented to be more easily invaded (Gerhold et al 2011). The habitat-based and geography-based explanations of the low abilities of species native to New Zealand to thrive within the stands of L. polyphyllus are definitelly not exclusive and it is very likely that they work together.…”

Functional and phylogenetic similarity of alien plants to co‐occurring natives

“…This phylogenetic similarity assumption implies that introduced aliens might be able to replace, or coexist with, natives depending on the native community's phylogenetic composition (clustered [even community] Fig. 1) and the spatial scale of the comparison (Proches et al 2008, Davies et al 2011, Gerhold et al 2011). In the case of clustered communities, space filling by aliens might be possible due to the absence of phylogenetically distant lineages (Strauss et al 2006), as natives in such communities have mostly been exposed only to closely related species.…”

“…In the case of clustered communities, space filling by aliens might be possible due to the absence of phylogenetically distant lineages (Strauss et al 2006), as natives in such communities have mostly been exposed only to closely related species. In the case of even communities, space filling by aliens might be possible due to the existence of functional gaps in the trait spectrum (Thuiller et al 2010, Gerhold et al 2011, or natives being naı¨ve to alien species from closely related lineages (favoring matching; Rejmanek 1996). Reality is a bit more complex, as the assembly process is determined by the perceived phenotype, not relatedness per se, making relatedness only useful when it captures the community composition of assembly-related traits because it serves as a proxy for the integrated phenotype and, thus, for unmeasured phenotypic traits.…”

“…While several studies indicate that there is an association between the relatedness of invasive aliens to the native biota and invasion success (e.g., Strauss et al 2006, Jiang et al 2010, Ricotta et al 2010, Davies et al 2011, Gerhold et al 2011, evidence of the opposite has also been recorded (as revised by Diez et al 2008, andThuiller et al 2010), and shown to depend on the comparison scale (Proches et al 2008, Thuiller et al 2010, Davies et al 2011). This conflicting evidence, encapsulated under the term Darwin's naturalization conundrum (Diez et al 2008), would seem to support two seemingly contradictory hypotheses: that introduced aliens are more likely to be successful when they are either phylogenetically similar (phenotypic similarity) or dissimilar (Darwin's naturalization hypothesis) to the native community.…”

“…For example, while some global studies (Ordonez et al 2010, van Kleunen et al 2010, Ordonez and Olff 2013 found support for the functional distinctiveness of invasive aliens when compared to natives, country-level comparisons in New Zealand (Diez et al 2008, Diez et al 2009) have provided support for the functional similarity between aliens and natives. Meanwhile, regional-level comparisons indicate no trend in the functional relatedness of aliens and natives Hulme 2006, Lambdon et al 2008), or whether traits of successful aliens are dependent on the phylogenetic structure of the recipient native community (across plots in the Netherlands; Gerhold et al 2011).…”