Worldwatch Paper #108: Life Support: Conserving Biological Diversity
Biological diversity—the ecosystems, species, and genes that together constitute the living world—is complex beyond our understanding, and valuable beyond our ability to measure. But it is clear that this diversity is collapsing at rates that can only be described as mind-boggling. Difficult as it is to accept, mass extinction has already begun, and the world is irrevocably committed to many further losses.
Harvard University biologist, Edward O. Wilson estimates that in tropical rain forests alone, roughly 50,000 species per year—nearly 140 each day—are either extinguished or condemned to eventual extinction by the destruction of their habitat. These figures are predictions based on theory rather than tallies of individual extinctions, but as measures of the erosion of life worldwide, they may be considered conservative. Habitat losses in other areas, such as tropical dry forests and rangelands, and other mechanisms of extinction, such as over-exploitation, pollution, and the introduction of exotic species, surely push the numbers higher.
Why should disappearing beetles, plants, or birds concern us? To biologists, and to many others, the question hardly needs asking: a species is the unique and irreplaceable product of millions of years of evolution, a thing of value for scientific study, for its beauty, and for itself. For many people, however, a more compelling reason to conserve biological diversity is likely to be pure self-interest: like every species, ours is intimately dependent upon others for its well-being.