PLANT LOSSES THREATEN FUTURE FOOD SUPPLIES AND HEALTH CARE
Widespread losses of plant species and varieties are eroding the foundations of agricultural productivity and threatening other plant-based products used by billions of people worldwide, reports a new study by the Worldwatch Institute, a Washington, DC-based research organization.
"Plants provide us with irreplaceable resources," said John Tuxill, author of Nature^s Cornucopia: Our Stake in Plant Diversity. "The genetic diversity of cultivated plants is essential to breeding more productive and disease resistant crop varieties. But with changes in agriculture, that diversity is slipping away." In China, farmers were growing an estimated 10,000 wheat varieties in 1949, but were down to only 1,000 by the 1970s. And Mexican farmers are raising only 20 percent of the corn varieties they cultivated in the 1930s.
"Biotechnology is no solution to this loss of genetic diversity," said Tuxill. "We are increasingly skillful at moving genes around, but only nature can create them. If a plant bearing a unique genetic trait disappears, there is no way to get it back."
The effects of plant loss extend far beyond agriculture. One in every four medicines prescribed in the United States is based on a chemical compound originally found in a plant. And worldwide some 3.5 billion people in developing countries rely on plant-based medicine for their primary health care. Plants also furnish oils, latexes, gums, fibers, timbers, dyes, essences, and other products we use every day. Rural residents of developing countries depend on plant resources for up to 90 percent of their total material needs.
Loss of habitat, pressure from non-native species, and overharvesting have put one out of every eight plant species at risk of extinction, according to the World Conservation Union.
"It is not just obscure or seemingly unimportant plants that are in trouble," said Tuxill. "Those that we rely upon most heavily are declining too. Some two thirds of all rare and endangered plants in the United States are close relatives of cultivated species. Crop breeders often turn to wild relatives of crops for key traits, like disease resistance, when they cannot find those traits in cultivated varieties.
Many medicinal plants are also in trouble from overharvesting and destruction of habitat. The bark of the African cherry tree is widely used in Europe for treating prostate disorders, but the medicinal trade has led to severe depletion of the tree where it grows in the highlands of Cameroon and other central African countries. Since fewer than 1 percent of all plant species have been screened for bioactive compounds, every loss of a unique habitat and its species is potentially a loss of future drugs and medicines. And traditional knowledge about medicinal plants is declining even faster than the plants themselves.
Until recently, gene banks, botanical gardens, and protected areas have been the first line of defense in maintaining the diversity of plant life. The world^s 1,600 botanical gardens, for example, collectively tend tens of thousands of plant species. But Tuxill notes that these conventional approaches need significantly higher levels of support. Many conservation facilities must scrape by on increasingly scarce funding, particularly those run by national governments. Only 13 percent of gene-banked seeds are in well-supported facilities with long-term storage capability. Protected area systems in many countries are also poorly developed.
As a result, governments, NGOs, and citizen activists are developing innovative partnerships to bring plant diversity back to the landscapes where we live and grow our food and material goods. Tuxill identifies a number of examples:
* In the U.S. state of Iowa, a farmers^ group and university researchers are identifying agronomic practices, such as alternative crop rotations and cover crop plantings, that can enhance biological diversity on farms and save farmers money on fertilizers and agrochemical inputs.
* Innovative plant breeders in developing countries are working directly with farmers in participatory breeding programs to evaluate, select, and improve locally adapted crop varieties while maintaining robust levels of genetic diversity.
* Consumers can buy timber products from nearly 10 million hectares of forest worldwide certified as being managed in an environmentally responsible manner under the guidelines of organizations like the Forest Stewardship Council.
* In the Central American nation of Belize, the government has established a rainforest reserve that is being managed by a local association of traditional healers for the production of wild medicinal plants.
* Throughout India, hundreds of thousands of hectares of degraded forestland are recovering under co-management arrangements between state forest departments and village associations.
Additional steps need to be taken to reform policies and practices that work against plant diversity. Some international bodies like the Convention on Biological Diversity (CBD) require governments to develop policies for managing plant resources wisely. However, others like the World Trade Organization (WTO) demand that countries dismantle these protective policies, labeling them barriers to free trade.
"The bottom line is that we have to share both the economic benefits of plant diversity and the obligation for protecting it," said Tuxill. "Those who garner the benefits of plant diversity, such as agribusinesses and pharmaceutical consumers, should acknowledge and support those who maintain it, like indigenous cultures and national gene banks." Through benefit-sharing agreements, international conservation endowments, and grassroots development projects attuned to the links between cultural and biological diversity, many options exist for supporting plant diversity rather than diminishing it.
NEWS FROM THE WORLDWATCH INSTITUTE: a press release on Worldwatch Paper 148, "Nature^s Cornucopia: Our Stake in Plant Diversity," by John Tuxill. Tuxill explores the multiple benefits we derive from plants, from agriculture to medicines, and what we stand to lose unless we halt the rapid extinction of plant species. September 21, 1999.