The importance of connections

Connections, everyone has them. Being “well-connected” means a lot in our society. It means everything in nature — it's a Web of Life. All species and populations in isolation accomplish little. It's only when they are linked that things begin to happen and ecosystems begin to work. Generally the more diverse things are, the more links there are and the better things function. (Tilman, 2000)

Biodiversity is in some ways very new science, although it's supported by years of study in related fields. In fact, the term “biodiversity” (a short form of the term biological diversity) wasn't used until 1985. There are still lots of uncertainties, and the complex, interactive, chaotic nature of the subject makes it hard to study, but some generalities are emerging from a developing body of scientific literature:

• greater biodiversity leads to greater productivity in plant communities;
• greater biodiversity reduces the relative size of productivity fluctuations brought on by seasonal change;
• greater biodiversity leads to greater nutrient retention in ecosystems;
• greater biodiversity leads to greater ecosystem stability (i.e. returns quickly to an equilibrium);
• ecosystem processes are less stable or reliable at lower diversity levels;
• greater biodiversity leads to greater resistance to invasive species;
• greater biodiversity leads to greater resistance to disease.
• removal or addition of any species can lead to big changes in community composition and structure. (Tilman, 2000; McCann, 2000)

So biodiversity is often a reasonable measure of how well an ecosystem functions and biodiversity is integral to the ecosystem.

One way to visualize the stability of diverse systems is to picture a diverse meadow and a manicured lawn containing nothing but one variety of grass. Imagine the relative impact of removing one important species from each system.