Biodiversity Made Simple: Richness and Evenness
Two crews each count a hundred trees and find four species. In one plot the counts are 25, 25, 25, and 25. In the other they are 85, 5, 5, and 5. The species totals match, but the abundance patterns differ. A pathogen that kills every tree of the dominant species could remove 85 trees from the secon
Population Regulation: How to Understand Density
Consider two events in the same beetle population. In July, crowding leaves late-hatching larvae with little food, and mortality among them approaches 70 percent. In October, an early freeze kills roughly 80 percent of the survivors. Both events reduce numbers. To distinguish them, ask whether reduc
