What is Biodiversity?

Ecosystems and biomes can be complex in any number of ways. Some ecosystems have a variety of geographic features that make it complex, while others have a wide variety of species. Biodiversity refers to the variety of the life that exists in a particular area. The most common measurement of biodiversity is the number of different species that live in the area. The complexity of the relationships between species in an area is another way to view biodiversity.

So, how do scientists measure biodiversity? Scientists use a biodiversity index to calculate the species diversity in an area. Here is how it is calculated :

# species in a study area / # individuals in the study area = biodiversity index.

The closer the index is to 1, the higher the biodiversity. For example, if an area had 300 pine trees, its biodiversity index would be @@1/300@@ or .003. This area has low biodiversity. If an area had 1 pine tree, 1 oak tree, 1 maple tree, 1 hickory tree, and 1 elm tree, its biodiversity would be @@5/5@@ or 1. This area has high biodiversity.

The biodiversity of an ecosystem affects the health of an ecosystem. The higher the biodiversity, the healthier the ecosystem. Determining how many different species exist in a particular ecosystem is key to understanding why it is important to preserve species diversity. A uniform population of a single species of plants adapted to a particular environment is more at risk if any changes occur to their ecosystem. A more diverse population consisting of many species of plants has a much better chance of including individuals who might survive and adapt to environmental changes.

Think about this scenario: what would happen if Dutch Elm disease spreads through 2 forest ecosystems (one which contains just elm trees and a second that contains elm, maple, hickory, and oak trees)? In the first forest ecosystem (the all elm tree ecosystem), most of the trees will not survive the epidemic, leaving little to no trees surviving in the ecosystem. No trees would have an effect on all of the other plants and animals living in the forest. But, the ecosystem that contains elm, maple, hickory, and oak trees may lose all its elm trees, but still have plenty of trees remaining in the ecosystem. Which forest would you rather live in if you were a squirrel?


Source: http://www.amnh.org/learn/biodiversity_counts/class_prep/biodiversity_index.htm (fair use