The Benefits of Biodiversity

Productive environments usually have many different species of plants and animals living in them. A rain forest is an example of a system with high biodiversity, whereas the Arctic tundra is an example of low biodiversity. Why are people concerned about the loss of species? What are the benefits of diversity?

Protection from Disease

In a diverse community, members of the same species are usually separated from one another. This makes it harder for a specific disease or insect to move easily from one host plant to another.

Protection from Changing Conditions, such as Climate Change

Most plants and animals have a range of temperatures, moisture conditions and light within which they thrive. These conditions best support the life of that species. When different species are found together, it is an indication that their ranges of tolerance overlap. For example, ants and fungi tolerate the same kind of soil, and moss and rhododendrons prefer acidic soil.

Overlapping species are also in a position to provide services to one another, such as shelter, warmth, and food. The red ant growing a fungi farm shares with the fungi an ability to live at a certain temperature, with a particular amount of moisture in the air and a certain amount of changing light. The fact that members of a community use each other for shade, food, and shelter means that the disappearance of one or more may lead to a chain reaction in which others are lost.

Changes ripple out: If the fungus dies because it can’t tolerate the change, the ant may die. Indeed, global climate change poses a threat to many communities. Studies of ice cores show that glacial periods were accompanied by widespread disintegration of plant and animal communities.

A community or ecosystem with greater diversity is generally more resistant to disturbances. The species within diverse systems provide numerous alternative methods for sustaining life, some of which will be more resistant to particular threats than others. Therefore, the community itself will endure.

Medicine

Many species, including humans, depend on new food and medicine supplies found in areas of great diversity. When we develop resistance to one medicine, for example, another may be found in an area of diverse plants to take its place.

The Costs of Monoculture

An acre of farmland growing only a single crop, called a “monocrop” (for example, rice, wheat, or corn), is another example of extremely low diversity, this one created by humans. Plant diseases and insects typically target specific species of plants. Therefore monocrops are very susceptible to disease and insect attack because both the microorganisms that cause plant disease and insects can multiply and move easily across the short distances to their next food source, the plant next door. As a result, farmers use a lot of pesticides to try to protect the crop.

Nothing Is Simple

Biodiversity, therefore, gives an ecosystem strength. But is that always true? As communities tend to age and become more complex, diversity usually reflects health. But there are exceptions. The edge between two vegetation communities (such as a forest and grassland) will typically be quite diverse because it contains members from both systems. In this case, diversity is not particularly an indication of health, only complexity. A forest, if left to age naturally, will reach a plateau or climax condition where several trees become dominant and prevent the multiplication of other species. This is a simplified, but healthy, condition.