Plant Diversity Richness

Diversity in single-celled and multicellular plants supports almost all food chains. Plant diversity influences the animal populations living in an area. Unfortunately, human activities have overburdened the world’s producers (plants), and this has contributed to animal extinction. Humans use 3 percent of the energy stored in plants for food, feeding livestock, and heating by the equation shown below. When people convert vegetated land to nonbiological uses—parking lots, buildings, marshes to dry land, grasslands to deserts—this amount increases to 30 percent.

Solar energy + carbon dioxide + water → glucose + oxygen

The total amount of the Sun’s energy held by plants is called gross primary productivity (GPP). The rest of the Sun’s energy dissipates as heat and is lost. Producers hold 100 percent of the energy they capture in their tissues. They use some of it for building plant tissue, also called maintenance- growth-reproduction (MGR), and the rest goes to provide
energy for every other living thing. This remainder on which animals depend is called net primary productivity (NPP).

NPP = GPP – MGR

Plant diversity runs the planet because different plants serve as producers in hundreds of food chains. Biologists measure plant diversity richness by analyzing the types of plants known to live in habitats within each biogeographic region. Plant range-incidence mapping shows that the United States contains plant diversity hotspots in the San Francisco Bay region, Hawaii, the Mojave Desert, the Smokey Mountain region of the Appalachian Range, and spots in Southern California.