%ACook‐Patton, Susan [AAAS Science &, Technology Policy Fellow 201 14th Street, SW Washington DC 20227 USA]%ACook-Patton, Susan [AAAS Science & Technology Policy Fellow; 201 14th Street, SW Washington DC 20227 USA]%AHastings, Amy [Department of Ecology and Evolutionary Biology; Cornell University; Ithaca NY 14853 USA]%AHastings, Amy [Department of Ecology and Evolutionary Biology Cornell University Ithaca NY 14853 USA]%AAgrawal, Anurag [Department of Ecology and Evolutionary Biology Cornell University Ithaca NY 14853 USA, Department of Entomology Cornell University Ithaca NY 14853 USA]%AAgrawal, Anurag [Department of Ecology and Evolutionary Biology; Cornell University; Ithaca NY 14853 USA; Department of Entomology; Cornell University; Ithaca NY 14853 USA]%ASemchenko, ed., Marina%ASemchenko, ed., Marina%BJournal Name: Journal of Ecology; Journal Volume: 105; Journal Issue: 3; Related Information: CHORUS Timestamp: 2023-09-11 16:52:29 %D2017%IWiley-Blackwell %JJournal Name: Journal of Ecology; Journal Volume: 105; Journal Issue: 3; Related Information: CHORUS Timestamp: 2023-09-11 16:52:29 %K %MOSTI ID: 10026961 %PMedium: X %TGenotypic diversity mitigates negative effects of density on plant performance: a field experiment and life cycle analysis of common evening primrose Oenothera biennis %XSummary

Genotypic diversity in plant populations is known to enhance plant performance and ecosystem function. Nonetheless, the effect of genotypic diversity has rarely been examined across a population's lifecycle despite the expectation that changing conditions, such as population density, will alter the benefits of diversity.

We simultaneously manipulated a component of genotypic diversity (richness, the number of genotypes) and density of common evening primroseOenothera biennisto address the consequences for herbivory and lifetime fitness in a 2‐year field experiment that spanned seed germination to lifetime fruit production. We genotyped >1100 seedlings with microsatelliteDNAmarkers to determine realized diversity and density in plots sown withO. biennisseeds. Our design achieved quantitative variation in plant density and diversity, with one to 44 individuals established in field plots and two to eight genotypes per polyculture plot (based on microsatellite analysis of reproductive plants).

We found a strong interaction between seed density and genetic diversity, with germination and establishment being 24% higher in genetic polycultures than monocultures, but only at low seed density. At high seed density, the opposite pattern emerged, with polycultures having 12% fewer individuals established than monocultures. Initial effects of emergence on plot density persisted through to the fruiting stage.

Higher plant densities resulted in increased mortality, decreased probability of reproduction, decreased plant height and lower levels of lifetime fruit production per plant. Increasing genotypic diversity increased the probability of reproduction overall and showed a significant interaction with plant density mitigating the negative effects of high density on individual height and lifetime fruit production.

Synthesis. Plant density and genotypic diversity interacted from the very early stages of seed germination and establishment ofOenothera biennis. This effect persisted over the 2‐year life cycle of plants, and genotypic diversity buffered against the negative fitness consequences of high plant density. These results imply a dynamic interplay between the long‐held paradigm of density effects in plant ecology and the genetic structure of populations.

%0Journal Article