@article{SoliveresMaestreUlrichetal.2015,
  author    = {Soliveres, Santiago and Maestre, Fernando T. and Ulrich, Werner and Manning, Peter and Boch, Steffen and Bowker, Matthew A. and Prati, Daniel and Delgado-Baquerizo, Manuel and Quero, Jose L. and Sch{\"o}ning, Ingo and Gallardo, Antonio and Weisser, Wolfgang W. and M{\"u}ller, J{\"o}rg and Socher, Stephanie A. and Garcia-Gomez, Miguel and Ochoa, Victoria and Schulze, Ernst-Detlef and Fischer, Markus and Allan, Eric},
  title     = {Intransitive competition is widespread in plant communities and maintains their species richness},
  series = {Ecology letters},
  volume    = {18},
  journal   = {Ecology letters},
  number    = {8},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {1461-023X},
  doi       = {10.1111/ele.12456},
  pages     = {790 -- 798},
  year      = {2015},
  abstract  = {Intransitive competition networks, those in which there is no single best competitor, may ensure species coexistence. However, their frequency and importance in maintaining diversity in real-world ecosystems remain unclear. We used two large data sets from drylands and agricultural grasslands to assess: (1) the generality of intransitive competition, (2) intransitivity-richness relationships and (3) effects of two major drivers of biodiversity loss (aridity and land-use intensification) on intransitivity and species richness. Intransitive competition occurred in >65\% of sites and was associated with higher species richness. Intransitivity increased with aridity, partly buffering its negative effects on diversity, but was decreased by intensive land use, enhancing its negative effects on diversity. These contrasting responses likely arise because intransitivity is promoted by temporal heterogeneity, which is enhanced by aridity but may decline with land-use intensity. We show that intransitivity is widespread in nature and increases diversity, but it can be lost with environmental homogenisation.},
  language  = {en}
}
@article{VenailGrossOakleyetal.2015,
  author    = {Venail, Patrick and Gross, Kevin and Oakley, Todd H. and Narwani, Anita and Allan, Eric and Flombaum, Pedro and Isbell, Forest and Joshi, Jasmin Radha and Reich, Peter B. and Tilman, David and van Ruijven, Jasper and Cardinale, Bradley J.},
  title     = {Species richness, but not phylogenetic diversity, influences community biomass production and temporal stability in a re-examination of 16 grassland biodiversity studies},
  series = {Functional ecology : an official journal of the British Ecological Society},
  volume    = {29},
  journal   = {Functional ecology : an official journal of the British Ecological Society},
  number    = {5},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {0269-8463},
  doi       = {10.1111/1365-2435.12432},
  pages     = {615 -- 626},
  year      = {2015},
  abstract  = {Hundreds of experiments have now manipulated species richness (SR) of various groups of organisms and examined how this aspect of biological diversity influences ecosystem functioning. Ecologists have recently expanded this field to look at whether phylogenetic diversity (PD) among species, often quantified as the sum of branch lengths on a molecular phylogeny leading to all species in a community, also predicts ecological function. Some have hypothesized that phylogenetic divergence should be a superior predictor of ecological function than SR because evolutionary relatedness represents the degree of ecological and functional differentiation among species. But studies to date have provided mixed support for this hypothesis. Here, we reanalyse data from 16 experiments that have manipulated plant SR in grassland ecosystems and examined the impact on above-ground biomass production over multiple time points. Using a new molecular phylogeny of the plant species used in these experiments, we quantified how the PD of plants impacts average community biomass production as well as the stability of community biomass production through time. Using four complementary analyses, we show that, after statistically controlling for variation in SR, PD (the sum of branches in a molecular phylogenetic tree connecting all species in a community) is neither related to mean community biomass nor to the temporal stability of biomass. These results run counter to past claims. However, after controlling for SR, PD was positively related to variation in community biomass over time due to an increase in the variances of individual species, but this relationship was not strong enough to influence community stability. In contrast to the non-significant relationships between PD, biomass and stability, our analyses show that SR per se tends to increase the mean biomass production of plant communities, after controlling for PD. The relationship between SR and temporal variation in community biomass was either positive, non-significant or negative depending on which analysis was used. However, the increases in community biomass with SR, independently of PD, always led to increased stability. These results suggest that PD is no better as a predictor of ecosystem functioning than SR.Synthesis. Our study on grasslands offers a cautionary tale when trying to relate PD to ecosystem functioning suggesting that there may be ecologically important trait and functional variation among species that is not explained by phylogenetic relatedness. Our results fail to support the hypothesis that the conservation of evolutionarily distinct species would be more effective than the conservation of SR as a way to maintain productive and stable communities under changing environmental conditions.},
  language  = {en}
}