Humankind, as a whole, has never faced the menace of having the factors that maintain it alive collapse. In your living area, an apple may be something banal, easy to get and perhaps diverse. But, while between 1804 and 1905 there were 7,098 types of apples cultivated in US, today 6,121 types (80 %) are extinct. 88 % of the 2,683 types of pears are gone. In 1949, in China there were cultivated 10,000 varieties of wheat; today just 1,000.
What are we losing in biodiversity does not refer just to species, but to varieties inside the species. In US, the diversity of vegetables lowered in 80 years by 97 %. 95 % of the varieties of cabbage, 91 % of corn, 94 % of pea, and 81 % of tomato are lost.
Biodiversity is essential for life on Earth, both for crops or plants living in pastures, and forests, but also inside the species. Having various types of rice grains, perhaps some could prove to be resistant to some bacterial diseases.
Plant extinctions affect crops in two ways: by destroying the wild progenitors (which is losing a source of genes), and by reducing the variety of the cultivated plant.
At the beginning of the 20th century, there were over 100,000 types of rice in Asia, and over 30,000 only in India. Today, 75 % of the rice production in India is based on 10 varieties. Sri Lanka had 2,000 types of rice, now just 5. Mexico, the cradle of the corn, has now just 30 % of all the varieties from 1930.
About 25 % of the drugs are achieved from plants and new medicine plants are continuously being discovered. Yet, they are also continuously disappearing. Out of potential 18,000 medicine plant species, 11,000 are menaced. The situation is catastrophic in Malaysia, Indonesia or Latin America, where forests are replaced by plantations, and this takes place at an amazing speed.
question is: how can an increasing human population with a decreased biodiversity be fed? Various countries started, for a long time now, making seed banks (over 1,000 by now, and some were even closed); and some botanical gardens aim to save endangered species. The Royal Botanical Gardens of Kew (England) aim to gather and preserve, till 2010, ten percent of world's plants (24,000 species) as seeds. 90 % of the seeds preserved in the seed banks belong to food plants and other species with various purposes.
The Irish case is illustrative. In 1840, Ireland had one of the highest demographic densities, over 8 million inhabitants, whose diet was based on the potato, the most cultivated variety being "lumper".
In 1845, a fungus called mildew destroyed almost all the harvest. Ireland resisted one year, but as they did not have other variety to seed, the disease stroke next year with a smashing power. The result: one million people died of hunger, 1.5 million people migrated, especially to US, and the others remained ruined.
In Andes, the cradle of the potato, there are many types of potatoes, and only some are affected by the mildew, thus there has never been an epidemic. Monoculture exposes the plant to diseases that can entirely destroy it. That's why many farmers depend on the continuous use of pesticides, herbicides, and fungicides, even if they destroy the environment.
Monocultures are the result of economical rules, because they are easier to harvest, more attractive, resistant to rotting and, thus, more productive. This tendency boomed during the '60s, with the so called "green revolution".
Companies and governments made campaigns aimed to convince the farmers to replace their varieties with extremely productive strains, especially of rice and wheat, seen as universal panacea against the hunger.
But, the seeds were costly: thrice the price of common ones. Moreover, the production depended on chemicals, such as fertilizers, not to mention tractors and other machinery. But the governmental subventions allowed the take off of the green revolution.
It worked for a short term, but it poses danger for a long term. Monocultures generalized worldwide, but the intensive use of fertilizers stimulated the weeds and the herbicides killing the weeds, and it also exterminated beneficial insects. In rice paddies, the chemicals killed fish, shrimps, crayfish, and frogs, and also comestible wild plants. Also, many farmers, who had been in contact with them, got intoxicated.
The green revolution eliminated 75 % of the biodiversity of the crop species. The genetic uniformity explains why in US a fungus produces huge damages in the corn fields, while in Indonesia, 200,000 hectares of rice paddies have already been lost.
Now, another revolution has been triggered: the genetic one. Biotechnologies work for increasing productivity and resistance to diseases, drought or cold, and to eliminate the need of using so many chemicals. The genetic engineering takes one gene from a species and inserts it into the DNA of another, transmitting the desired trait. For example, a gene from an Arctic fish, like the flounder, encoding the synthesis of an anti-freeze chemical could be introduced into a potato or strawberry in order to increase their resistance to frost. In fact, researchers can manipulate genes from bacteria, viruses, insects, mammals and even humans, and insert them into plants.
But, the biotechnologies further increase the issue of the uniformity, as through cloning and tissue cultures there can be obtained new organisms, which are complete copies of the progenitors. And the results of using engineered crops are still not very clear.
Seeds found in seed banks also have a limited lifespan. When their energy reserves are gone, they die. And the keeping of these banks is costly: $ 300 million annually. And only 13 % of the seeds are properly stored for long term. The National Seed Storage Laboratory from Colorado (US) has experienced many difficulties, such as malfunction of the electric supply and refrigeration equipment, which left many seeds unclassified. The banks are vulnerable to political, economical or natural issues.
Also, long term storing is believed to make many seeds lose properties. But, well guarded seeds can last for centuries. Today, 30 countries have long term seed banks.
In the end, the best solution is to protect local habitat, and the crop biodiversity as well.
100 years ago, hundreds of millions of farmers worldwide controlled their seed reserves. Now, they come from multinational companies, which treat them like intellectual property. Since 1950, the number of farmers in the western world has decreased by 80 % in some countries. The exodus is caused by low income, the increase of rural debt and poverty and the continuous mechanization.
In 1910, American farmers received 40 cents for each dollar spent by the consumers on food; in 1997, this had decreased to 7 cents. For wheat, this is 6 cents. When buying bread, you pay more for the wrapping than for the wheat. And if in developed countries farmers can pass a bad year through bank credits, in Africa a bad year will mean the ruin of the farmer.