title: Evolutionary history determines how plant productivity responds to phylogenetic diversity and species richness.
abstract: The relationship between biodiversity and ecosystem function has received a great deal of attention in ecological research and recent results, from re-analyses, suggest that ecosystem function improves with increases in phylogenetic diversity. However, many of these results have been generalized across a range of different species and clades, and plants with different evolutionary histories could display different relationships between biodiversity and ecosystem function. To experimentally test this hypothesis, we manipulated species richness and phylogenetic diversity using 26 species from two subgenera of the genus Eucalyptus (subgenus Eucalyptus and subgenus Symphyomyrtus). We found that plant biomass (a measurement of ecosystem function) sometimes, but not always, responded to increases in species richness and phylogenetic diversity. Specifically, Symphyomyrtus plants showed a positive response while no comparable effect was observed for Eucalyptus plants, showing that responses to biodiversity can vary across different phylogenetic groups. Our results show that the impacts of evolutionary history may complicate the relationship between the diversity of plant communities and plant biomass.
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Tennessee-Knoxville , Knoxville, TN , USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Genung
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Tennessee-Knoxville , Knoxville, TN , USA.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Schweitzer
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Tennessee-Knoxville , Knoxville, TN , USA.
authors.forename: Joseph K
authors.initials: JK
authors.lastname: Bailey
keywords: Biodiversity; Ecosystem function; Evolutionary history; Phylogeny; Species interactions; Species richness