High species richness → greater stability: less year-to-year variation in biomass, higher resistance/ resilience to perturbations, and reduced variability in ecosystem processes (e.g., water use, pest/disease cycles). Area with high species richness shows less year-toyear variation in total biomass. Region that is less seasonal, relatively more constant and predictable has higher species richness. Loss of biodiversity in a region may lead to lowered resistance to environmental perturbations such as drought.