Rapid transgenerational effects in Knautia arvensis in response to plant community diversity

Abstract

1. Plant species persistence in natural communities requires coping with biotic and abiotic challenges. These challenges also depend on plant community composition and diversity. Over time, biodiversity effects have been shown to be strengthened via increasing species complementarity in mixtures. Little is known, however, whether differences in community diversity and composition induce rapid transgenerational phenotypic adaptive differentiation during community assembly. We expect altered plant-plant and other biotic interactions (mutualists or antagonists) in high vs. low diverse communities to affect immediate within-and between-species trait differentiations due to competition for light and nutrients. 2. Three years after the initiation of a large-scale, long-term biodiversity experiment in Jena, Germany, we tested for effects of varying experimental plant community diversity (1-60 plant species; one to four plant functional groups) and composition (with or without legumes and/or grasses) on phenotypic differentiation and variation of the tall herb Knautia arvensis. We measured reproduction at different diversity levels in the Jena Experiment (residents hereafter) and, in an additional common garden experiment without competition, recorded subsequent offspring performance (i.e. growth, reproductive success and susceptibility to powdery mildew) to test for differentiation in phenotypic expression and variability. 3. We observed phenotypic differences among diversity levels with reduced fecundity of K. arvensis residents in more diverse communities. In the next generation grown under common garden conditions, offspring from high-diversity plots showed reduced growth (i.e. height) and lower reproduction (i.e. fewer infructescences), but increased phenotypic trait variability (e.g. in leaf width and powdery mildew presence) and also tended to be less susceptible to powdery mildew infection. 4. Community composition also affected Knautia parents and offspring. In the presence of legumes, resident plants produced more seeds (increased fecundity); however, germination rate of those seeds was reduced at an early seedling stage (reduced fertility). 5. Synthesis. We conclude that rapid transgenerational effects of community diversity and composition on both mean and variation of phenotypic traits among offspring exist. In addition to heritable variation, environmentally induced epigenetic and/or maternal processes matter for early plant community assembly and may also determine future species coexistence and community stability. Recently, a largely positive diversity-ecosystem functioning relationship has been acknowledged (e.g. Mace et al. 2010; Hooper et al. 2012) based on observed diversity effects across trophic levels (Scherber et al. 2010) influencing multiple ecosystem functions (Lefcheck et al. 2015) and maintaining ecosystem services over time (Hector et al. 2010; Isbell et al. 2011). As a baseline, plants may adapt their phenotypes to different environments depending on the strength of selection and the amoun...

Community evolution increases plant productivity at low diversity

“…Open circles and dashed line refer to communities of co-selected plants, closed circles and solid line refer to na€ ıve communities. abiotic or biotic conditions have been observed in previous studies (Lipowsky et al 2011;Zuppinger-Dingley et al 2014;Kleynhans et al 2016;Rottstock et al 2017). Here, we demonstrated that changes in the performance of entire plant communities over time depend on a history of co-selection among the plant species of the assembled mixtures.…”

“…; Rottstock et al . ). Here, we demonstrated that changes in the performance of entire plant communities over time depend on a history of co‐selection among the plant species of the assembled mixtures.…”

“…Recent evidence suggests that selection of particular genotypes from the total genetic pool of a species may affect ecosystem functioning in field experiments (Strauss et al 2008;Lipowsky et al 2011;Lau & Lennon 2012;Kleynhans et al 2016;Rottstock et al 2017). We propose that co-selection of genotypes from the gene pool of entire communities may affect ecosystem functioning if non-random niche or trait changes in response to other phenotypes in the community result in more specialised niches with reduced overlap and a more complete use of biotope space (Dimitrakopoulos & Schmid 2004;Jousset et al 2011), thus leading to increased plant community productivity.…”

“…; Rottstock et al . ). We propose that co‐selection of genotypes from the gene pool of entire communities may affect ecosystem functioning if non‐random niche or trait changes in response to other phenotypes in the community result in more specialised niches with reduced overlap and a more complete use of biotope space (Dimitrakopoulos & Schmid ; Jousset et al .…”

Evidence for rapid evolution in a grassland biodiversity experiment

“…The emergence of such monoculture and mixture types, with different growth 100 performance and plant functional trait variation, thus suggested that community 101 diversity in the field likely acted as a selective environment (Zuppinger-Dingley et al, 102 2014; Rottstock et al, 2017;van Moorsel et al, 2018b). However, direct evidence for 103 a genetic divergence between the different populations in the field experiment is still 104 missing.…”