111 -0.5 Drought resistance (change in biomass 1986–198 -1.0 After D. Tilman and ), A. Downing. 1994. Nature 367:363--365. -1.5 0 15 25 5 10 20 Plant species richness before drought Tilman and Downing studied the impact of plant species richness on drought resistance in prairie communities. What conclusion can you draw from their figure? Communities with more species before the drought lost less biomass during it Communities with fewer species before the drought lost less biomass during it Communities with intermediate species before the drought lost less biomass during it The number of species within the community did not affect biomass during drought