Evaluating Darwin’s Naturalization Hypothesis in Experimental Plant Assemblages: Phylogenetic Relationships Do Not Determine Colonization Success

Abstract

Darwin’s naturalization hypothesis (DNH) proposes that colonization is less likely when the colonizing species is related to members of the invaded community, because evolutionary closeness intensifies competition among species that share similar resources. Studies that have evaluated DNH from correlational evidence have yielded controversial results with respect to its occurrence and generality. In the present study we carried out a set of manipulative experiments in which we controlled the phylogenetic relatedness of one colonizing species (Lactuca sativa) with five assemblages of plants (the recipient communities), and evaluated the colonizing success using five indicators (germination, growth, flowering, survival, and recruitment). The evolutionary relatedness was calculated as the mean phylogenetic distance between Lactuca and the members of each assemblage (MPD) and by the mean phylogenetic distance to the nearest neighbor (MNND). The results showed that the colonization success of Lactuca was not affected by MPD or MNND values, findings that do not support DNH. These results disagree with experimental studies made with communities of microorganisms, which show an inverse relation between colonization success and phylogenetic distances. We suggest that these discrepancies may be due to the high phylogenetic distance used, since in our experiments the colonizing species (Lactuca) was a distant relative of the assemblage members, while in the other studies the colonizing taxa have been related at the congeneric and conspecific levels. We suggest that under field conditions the phylogenetic distance is a weak predictor of competition, and it has a limited role in determining colonization success, contrary to prediction of the DNH. More experimental studies are needed to establish the importance of phylogenetic distance between colonizing species and invaded community on colonization success.

The community ecology of invasive species: where are we and what's next?

“…In contrast, most studies exploring the effects of phylogenetic relatedness between invasives and natives on community resistance (i.e. phylogenetic species‐based indices) have yielded mixed (Jones et al , Liu et al , Poe , Lososová et al , Marx et al ) or non‐significant results (Castro et al , Fleming et al ). Nevertheless, a recent study by Tan et al () in a manipulative experiment with bacterial assemblages found evidence that phylogenetic relatedness to invaders was a better predictor of biotic resistance than the phylogenetic diversity of the community.…”

Mycorrhizae, invasions, and the temporal dynamics of mutualism disruption

“…; Castro et al . ) or how often plants will show a phylogenetic signal for mycorrhizal fungi (Montesinos‐Navarro et al . ).…”

Deconstructing Darwin's Naturalization Conundrum in the San Juan Islands using community phylogenetics and functional traits

“…To assess 'Darwin's Naturalization Conundrum' (DNC, Diez et al, 2008), the use of phylogenies is becoming standard (e.g. Strauss et al, 2006b;Cadotte et al, 2009bCadotte et al, , 2010Davies et al, 2010;Schaefer et al, 2011;Carboni et al, 2012;Bezeng et al, 2013;Park & Potter, 2013;Castro et al, 2014;Lim et al, 2014;Ordonez, 2014;Li et al, 2015;Lososov a et al, 2015). The inclusion of evolutionary information using a phylogenetic approach provides an accurate quantification of relatedness by comparing phylogenetic distances (i.e.…”

“…The inclusion of evolutionary information using a phylogenetic approach provides an accurate quantification of relatedness by comparing phylogenetic distances (i.e. difference in branch lengths) between native and invasive species (Proches ß et al, 2008;Cadotte et al, 2009b;Thuiller et al, 2010), and relatedness has been shown experimentally to be a useful predictor of invasion success (Jiang et al, 2010;(Cadotte & Strauss, 2011), but see Castro et al, 2014). In addition, because related species are more likely to share ecologically relevant functional traits (Webb et al, 2002), phylogenetic distance as measured on a molecular phylogeny of the species within a community is often viewed as a proxy for ecological similarity (Cadotte et al, 2009a).…”