Remember the dinosaurs? Kings of the hill for 150 million years, then phttt, gone, poster animals of mass extinction. There have actually been five mass extinctions in the Earth's past — and we're well on our way to number six, says Peter Raven, an expert in plant conservation.
By the second half of the next century, between one-third and two-thirds of all plant and animal species, most in the tropics, will be lost, Raven, who is the director of the Missouri Botanical Garden, said Monday at the XVI International Botanical Congress in St. Louis.
In each of the prior mass extinctions, somewhere between one-fourth and one-half of all species died out over the course of a few million years — half a heartbeat in geologic times.
Two points make this mass extinction episode different from prior episodes. First, this extinction event is happening in hundreds, not hundreds of thousands or millions of years. Second, though the cause of the prior extinctions is up for debate, all were the result of natural phenomena. This is the first time that one species — homo sapiens — is the direct cause of the extinctions.
Conservation International is sponsoring a trip down the Pastaza River to catalog the flora and fauna of the Amazon rain forest.
The population explosion and its consequences are held as the culprits. Human activities, including the clearing of forests, the spread of agriculture, the introduction of animals into new environments, and the pollution of air, water, and soil, account for almost all of the extinctions of the last several thousand years..
Scientists have calculated what they call a background extinction rate — the rate at which species have been becoming extinct for the past 65 million years, since the last major extinction. The current extinction rate is now approaching 1,000 times the background rate and may climb to 10,000 times the background rate during the next century, Raven says.
Raven, who is a botanist and thus focused on plants rather than animals, presented a seven-point plan to slow the extinction rates of plants around the world in his presentation:.
- Establish a coordinating body, through the United
Nations or one of its constituent organizations -- to monitor
the status of plants throughout the world, detect those most in danger and take
steps to conserve them.
- Increase financial support for the study of plants throughout the world
- Make information on plants accessible on the Internet
- Place more emphasis on alien-introduced plants and animals as a major cause
of biodiversity losses.
- At the national level in every country around the world, maintain an active
census of the country's plants and their condition.
- Place special attention on conserving medicinal plants
- Internationally fund an ongoing program of research on plant population
biology and reproductive characteristics.
Held only once every six years, more than 4,000 scientists from 100 countries are meeting at the International Botanical Congress this week to discuss the latest results of research on plants for human survival and improved quality of life.