The term biodiversity simply means biological diversity. It is often thought of as the sum total of all species, genes, and natural communities occurring in a given area. The more biodiverse a habitat is the healthier it is. Conversely, the less biodiversity a habitat has (i.e., the fewer species or communities), the more degraded the habitat. When you hear the term "intact habitat," it usually means that there is a high level of biological diversity in that habitat.
Biological diversity is relative to the habitat or biome. A healthy, intact, biodiverse tropical rainforest may have as many as 200 species of tree per acre and several hundreds of species of nesting birds. Whereas a very healthy, biologically diverse temperate forest in the Midwest may have only 20-35 species of tree per acre and 50-80 species of nesting birds. Therefore, biodiversity cannot be determined solely by the number of species in a given area. It is also important to consider the habitat type and biome.
Preserving biodiversity is important for many reasons. First, the more diverse an ecosystem, the more likely it is to recover from a natural or artificial disaster. Second, the collection of species in the ecosystem acts as an orchestrated team, processing energy inputs and outputting usable byproducts. Over tens of thousands of years, complex interactions between species have evolved. As the number of species declines in an ecosystem, crucial interactions are lost. It is not clear what environmental consequences these lost interactions may have. Finally, a biologically diverse ecosystem is a place of wonder, joy and inspiration.
