Data from: Amount or pattern? Grassland responses to the heterogeneity and availability of two key resources

Patterns of resource availability and heterogeneity shape the composition, productivity, and dynamics of plant assemblages in a wide variety of terrestrial ecosystems. Despite this, the responses of plant assemblages to simultaneous changes in the availability and heterogeneity of more than a single resource are virtually unknown. To fill this gap, microcosms consisting of assemblages formed by Lolium perenne, Plantago lanceolata, Anthoxantum odoratum, Holcus lanatus, and Trifolium repens were grown in a factorial experiment with the following treatments: nutrient availability (NA), water availability (WA), spatial nutrient heterogeneity (NH), and temporal water heterogeneity (WH). Assemblages exhibited precise root foraging patterns in response to nutrient heterogeneity, which were modified by NA and WA. A series of two- and three-way interactions involving the four factors evaluated determined biomass production, the belowground : aboveground biomass ratio, the patterns of root biomass allocation with depth, and the relative contribution to aboveground biomass of Lolium and Anthoxanthum. In all cases, these interactions explained significant amounts of the variation found in the data. Our study demonstrates that considering the interactions between resource availability and heterogeneity allows for a refinement of predictions that can detectably reduce the error associated with extrapolating from single factor analyses.Data from a greenhouse experiment aiming to test the effects of the heterogeneity and availability of water and nutrientes on plant community attributesData from a greenhouse microcosm experiment. The experiment had four treatments: nutrient availability (three levels: 40, 80 and 120 mg of N added as organic material), nutrient heterogeneity (two levels: organic material added homogeneously or as a patch), water availability (three levels: 125, 250 and 375 mL of water added per week) and water heterogeneity (two levels: watering five times a week or watering once a week). Microcosm contained assemblages formed by the grasses Lolium perenne L., Anthoxantum odoratum L. and Holcus lanatus L., the forb Plantago lanceolata L. and the legume Trifolium repens L. The following data were collected at the end of the experiment: total above- and belowground biomass (0-15 and 15-30 cm depth) at the assemblage level, aboveground biomass at the species level, root foraging precision at the assemblage level.Maestre_Ecol88.tx