Coevolution between invasive and native plants driven by chemical competition and soil biota

Abstract

Although reciprocal evolutionary responses between interacting species are a driving force behind the diversity of life, pairwise coevolution between plant competitors has received less attention than other species interactions and has been considered relatively less important in explaining ecological patterns. However, the success of species transported across biogeographic boundaries suggests a stronger role for evolutionary relationships in shaping plant interactions. Alliaria petiolata is a Eurasian species that has invaded North American forest understories, where it competes with native understory species in part by producing compounds that directly and indirectly slow the growth of competing species. Here I show that populations of A. petiolata from areas with a greater density of interspecific competitors invest more in a toxic allelochemical under common conditions. Furthermore, populations of a native competitor from areas with highly toxic invaders are more tolerant to competition from the invader, suggesting coevolutionary dynamics between the species. Field reciprocal transplants confirmed that native populations more tolerant to the invader had higher fitness when the invader was common, but these traits came at a cost when the invader was rare. Exotic species are often detrimentally dominant in their new range due to their evolutionary novelty; however, the development of new coevolutionary relationships may act to integrate exotic species into native communities.allelopathy | glucosinolates | mycorrhizae | Pilea pumila

A novel impact of a novel weapon: allelochemicals in Alliaria petiolata disrupt the legume-rhizobia mutualism

“…However, it has been shown that concentrations of these chemicals can evolve in response to the density of non-A. petiolata plants in the community (Lankau 2012) and will vary predictably based on the age of a particular A. petiolata population (Lankau et al 2009). Our estimate was in line with previous measures of sinigin in nearby Michigan populations, which found an average of 43.78 lmol/g in A. petiolata populations ranging from 21 to 67 years in age (R. Lankau, personal communication).…”

Climate and rapid local adaptation as drivers of germination and seed bank dynamics of Alliaria petiolata (garlic mustard) in North America

“…). Furthermore, there is evidence that some native species have adapted to A. petiolata presence and chemistry including microbial communities (Lankau ), many native plants (Lankau , ; Lankau & Nodurft ) and the butterfly Pieris oleracea (Morton et al . ).…”

Local biotic adaptation of trees and shrubs to plant neighbors

“…The majority of these past studies focus on contrasting performance between one species that occurs with (sympatric) or without (allopatric) one other species in common transplanted environments. Character displacement resulting from asymmetric competition is the most frequently suggested mechanism of biotic adaptation (Martin and Harding , Vavrek , Proffitt et al , Fridley et al , Lankau ). Our experimental design builds on the sympatric/allopatric treatment used in prior studies but is unique in contrasting communities of three co‐occurring woody species in sympatry and allopatry.…”