Biodiversity (or better, Biological Diversity) is the total variety of genetic strains, species and ecosystems. It is a wonder and a delight, but also a great responsibility. There are an estimated 5 to 30 million species of animals and plants worldwide, and most remain unidentified. Biodiversity is not uniformly distributed over the earth’s surface. The tropics cover 42% of all land but contain two-thirds of all animal species. Rainforests cover 6% of all land but contain two-fifths of all plant and animal species. The numbers of species in a site is a simple index of biodiversity.
Biodiversity is important because:
Humans depend on the natural world for food, clothing and other necessities. About 3,000 plant species are used worldwide as food, but only 20 provide more than 80% of this total.
Biodiversity is essential for many eco-system services, such as nutrient cycling, soil formation, watershed protection, waste disposal, pollination, oxygen production, carbon sequestration and climate regulation.
Many species are important for the survival of other species even though they may not be of immediate use to humans.
Wild organisms have contributed significantly to human art, literature and religion. Christianity values biodiversity as a potent reminder of God’s personality, power and creative genius (Rom.1:20; Psalm 104). Many religions recognize that creation has a value apart from its usefulness to humanity. For Saint Francis landscapes, nature, plants and animals reminded him of the greatness of the Creator, which led him to an understanding of universal brotherhood with all of creation.
Many uses of species or nature are still to be discovered.
But despite its importance, biodiversity is threatened in many ways by human behavior:
The greatest threat is loss and fragmentation of natural habitats, which includes clearing forests for timber or farming, overgrazing, draining wetlands and the destruction of heath lands and coral reefs.
Pollution also degrades habitats. Pesticides, sewage, oil, combustion emissions and acid rain contaminate soil, water and air. One alarming effect of atmospheric pollution is accelerating changes in climatic patterns.
Over-exploitation has pushed some species to the verge of extinction, including the tiger, giant panda, black rhinoceros, cod and several whale species.
Other threats include: population growth, consumption, climate change and the model of development practiced today.
As a result of these multiple human threats, rates of extinction are now estimated to be between 1,000 and 10,000 times greater than in the recent past. Tropical forests are being destroyed at the rate of 0.8 to 2.0% per annum, causing the extinction of some of their estimated 5 million species. Since 1600 AD, we know that 484 animal species and 654 plant species have become extinct.
For more information in several languages on this topic we recommend you consult the ‘The Millennium Ecosystem Assessment’
written by Br. Bernd Beermann ofm cap