NATS 1940 Lecture Notes - Lecture 27: Species Richness, Species Evenness, Diversity Index
Document Summary
Diversity declines moving away from the equator. Latitude alone does not account for the observed patterns. Temperature alone was not a good predictor of local species richness in 2 tests done. More photosynthesis more plant material more animals. Sunlight is more intense near the equator. Land area in the tropics may also be a contributing factor to its high diversity rates. The total mass of plants produced per unit area and time via photosynthesis. A better predictor of diversity than latitude or temperature alone. Amount of solar energy captured by photosynthesis ( due to water availability and sunlight) accounts for latitudinal species richness gradient. Rate of photosynthesis increases with increasing temperature up to a point. Max rate of photosynthesis is higher and occurs at a higher temperature for tropical than temperate plants. More plant biomass the more complexity of vegetation structure (stratification/ layering) Temperate forests have fewer layers than tropical.