Threats to Biodiversity

Abstract

When human beings emerged biodiversity was at its peak. Population growth and concurrent destruction of the environment have caused this diversity to sink to the lowest level in 65 million years. The loss of biodiversity cannot be reversed making it perhaps the most important consequence of environmental change. Biodiversity is 1 of our planets most important resources. We have not yet studied or even valued the earths plants and animals many of which hold immense potential. For example the rosy periwinkle plant (Catharanthus roseus) growing in Madagascar produces vincristine and vinblastine which effectively treat Hodgkins disease and acute lymphocytic leukemia. Yet there are 5 other Catharanthus species which scientists have not yet studied thoroughly. Habitat destruction has placed 1 species in danger of extinction. Even small perturbations in a species rich apparently stable physical environment can cause the whole ecosystem to fall. The greatest pressure on biodiversity has been on isolated and distinctly cyclic environments such as lakes and islands. For example in the 1800s complete deforestation of the small island in the South Atlantic St. Helena resulted in extinction of its unique trees and shrubs. At the present annual rate of deforestation (1%) the world is losing .2-.3% of all forest species each year (4000-6000 species). This is 10000 times greater than the naturally occurring background extinction rate. Global warming is also contributing to the loss of biodiversity especially in cold temperature and polar regions. To slow the loss of biodiversity developed and developing countries must increase taxonomic inventories and reference libraries to map species and identify hot spots for priority in conservation. Economic development must accompany species conservation particularly in countries with impoverished populations and great population growth. Sustained harvesting of natural forest products can generate more income than clear cutting and agriculture.