Root biomass data: BAC: Biodiversity and Climate

Climate changes forecast for our region by GCM's and shifts in biodiversity and composition each have the potential to alter ecosystem functioning; their interactive effects are unknown. The "BAC" experiment is designed to determine the direct and interactive effects of plant species numbers, plant community composition, temperature, and precipitation on 11 productivity, C and N dynamics, stability, and plant, microbe, and insect species abundances in CDR grassland ecosystems.

The experiment uses a subset of 42 plots from the Biodiversity experiment: 14 monoculture plots (one randomly chosen replicate for each of the 14 non-woody species that became well established in monoculture), 14 plots planted to 4 species (randomly chosen from 4-species plots planted with combination of these 14 species), and 14 plots planted to 16 species (randomly chosen from all 16 species plots containing these 14 species). Plant species are from 4 different functional groups (4 species, each, of C3 grasses, C4 grasses, legumes and non-legume forbs) that are likely to respond differently to changes in temperature and water availability. Treatments, to be applied to 4 subplots (3 m x 4 m each) within each of these 42 plots, will create conditions that are (a) warmer than ambient, (b) warmer and watered, (c) ambient temperature but watered, and (d) un-warmed and un-watered, i.e., a full factorial of ambient or elevated temperature and of ambient or elevated precipitation. Temperature will be increased using infrared heat lamps (DeValpine and Harte 2001, Kimball 2005), and increased precipitation using automatic sprinklers; both methods were tested and refined in 2005.