Biodiversity is the variety of living organisms that live on earth, the ecological complexes they belong to, and the relationships these living organisms have with one another and their environment.

Environmentalists have divided the earth into distinct regions dictated by latitude, elevation, wind patterns, temperature, rainfall and the living organisms that have adapted to these specific conditions. The terrestrial regions include desert, grassland, tundra, tropical rainforest, deciduous forest, etc. Aquatic regions are divided into freshwater and marine systems based on the amount of salt contained in the water. These ecosystems, including the plants and animals living in them, are known as biomes.

The Sonoran Desert, because of its location (stretching from the Gulf of California to the Mogollon Rim in Arizona), and rainfall (3 – 15 inches annually) contains biotic communities representing all the world’s biomes. This makes the Sonoran Desert the most biodiverse desert in the world.

The biodiversity of a biome is an important measure of the health of that biome because ecosystem productivity goes up as biodiversity goes up. Each species, no matter how insignificant it may seem, plays an important role in the sustainability of the ecosystem. For example, the larger the number of plant species, the greater variety of crops available for food. This makes it less likely the ecosystem will fail if one species suffers a catastrophic event. The large genetic diversity of the living members in a healthy biome also helps the biome to better withstand and recover from a variety of disasters. The phrase ‘a balanced ecosystem’ reflects an ecosystem with a high amount of biodiversity, like the Sonoran Desert.

A healthy biome provides to all living things:

  • Ecosystem services, such as
    • Protection of water resources
    • Soil formation and protection
    • Nutrient storage and recycling
    • Pollution breakdown and absorption
    • Contribution to climate stability
    • Recovery from unpredictable events
  • Biological resources, such as
    • Food
    • Medicinal resources and pharmaceutical drugs
    • Breeding stocks and population reservoirs
    • Future resources
    • Diversity in genes, species and ecosystems
  • Social benefits, such as
    • Research, education and monitoring
    • Recreation and tourism

“When we try to pick out anything by itself, we find it hitched to everything else in the Universe.”

John Muir

The preceding list of services reprinted with permission from