The United Nations have declared this year the International Year of Biodiversity and many of you may wonder what exactly that is, its aims and what we – as humans and gardeners - should be doing to help.
The disappearance of species is a natural progress which is often called evolution, but it is currently estimated that species of plants and animals are disappearing at one hundred times the “normal” rate. By normal rate we mean based on very long term data, ranging back through fossils to modern day.
It's important that we stop and think how important plant biodiversity is. Plants help natural processes such as air and water purification; they absorb carbon and renew our oxygen supply; they help the absorption and detoxification of human and industrial wastes; their diversity aids pollination and, thus, cropping; they can aid pest control; they are important in flood and erosion control; they moderate our climate and atmosphere. They are vitally important in our economic processes; if the plants weren't there performing all these tasks, we, as taxpayers, would have an enormous bill!!
It's been estimated that there are around 30,000 edible plants on our earth but we, now, only use around 150 and, of those, only 30 regularly. Nowadays 90% of our food is supplied by only 15 plant species and 8 animal species of the many thousands that there are! It's equally important to note that some 70% of plant species are now considered under threat.
The figures are stunning. The Incas and Aztecs harvested from a glorious 3,000 varieties of potato; nowadays we recognise around 250 varieties but very much less are commercially grown. Equally, there are around 1,000 varieties of mango but only 4 or 5 are commercially grown. We are only just starting to fully realise the importance of diversification in our plantings. Crop monocultures are extremely vulnerable to disease and ensuing famine.
Wheat, rice and maize supply 60% of the world's food intake. In a typical African diet, the staple foods are cereals 46%, roots/tubers 20% and animal products 7%. Conversely, a Western European diet would be composed of cereals 26%, roots/tubers 4% and animal products 33%. But, bear in mind, that most of those animals feed on cereals - hectares and hectares of cereals.
So, foods of the past are being re-evaluated and, in particular, cereals and grains. Amaranth and quinoa are both grains that originated in the Andes and were regarded as holy plants by the Incas and Aztecs. They are both highly nutritious. Amaranth thrives in hot climates yet is hardy; quinoa will grow at 4000m. They are just two examples of crops that have, until very recently, been virtually lost to us – yet 900 million worldwide are starving. Many more plants await a re-awakening and wider usage.
Wild plants have always played an important role in rural communities and even today at least 1million people are believed to use them regularly. We, thankfully, still see plenty evidence of this in Spain. Two or three women walking along the roadside clutching hinojo (fennel) or bunches of wild asparagus is still a common sight.
The advice from the United Nations is – plant food now and, preferably, of species that aren't seen in our supermarkets. The more variety we can introduce, the better. Self-sufficiency is a rather massive undertaking and many of us gardeners won't want to commit to so much but, for example, 10% is quite do-able and would have a huge impact on the world market.
If you're filled with enthusiasm and want to see some results quickly, try sprouting seeds – within a few days you'll have crops! Then get your vegetable plot going – try unusual varieties – we'll be getting some really rare seeds in soon at the garden centre - old varieties with extra good taste etc. At the same time, revitalise neglected fruit trees in your garden; with a bit of tender loving care they can quickly be brought back into production. And, finally, plant more fruit trees and shrubs. With a little effort (which will give you lots of pleasure too), you'll soon be harvesting your own crops.
Biodiversity is variety of life on earth and it is essential to human existence. Remember that, when we talk of plants and animals becoming endangered, we are including ourselves, and our children, in that equation.