What Does Biodiversity Have To Do With Agriculture?

Source: Food and Agriculture Organization of the United Nations, 2013, Ruth Raymond and Amanda Dobson, Bioversity International,   "The Youth Guide to Biodiversity" 1st Edition (Chapter 9) Youth and United Nations Global Alliance. Reproduced with permission.

Chapter 9. Verbatim.

Agriculture depends on the diversity of relatively few plant and animal species. Approximately 250 000 plant species have been identified, 7 000 of which can be used as food. But only 150 crops are cultivated on any significant scale worldwide and only three (maize, wheat and rice) supply nearly 60 percent of the protein and calories in the human diet.

Given its heavy dependence on just a few food species, humanity relies on the diversity within these species to survive. This diversity can be considerable. For example, there are tens of thousands of different varieties of rice, developed by farmers over millennia. The International Rice Research Institute in the Philippines holds about 110 000 samples of different rice varieties in cold storage. 

Crop varieties may differ in plant height, yield, seed size or colour, nutritional qualities or flavour. They may respond differently to cold, heat or drought. Some varieties have the ability to withstand pests and diseases that would prove fatal to others. 

In the wild, biodiversity is the result of natural selection: the evolution of animals and plants to meet the challenges of their environment. In the field, this is the result of thousands of years of human activity. In addition, tremendous agricultural biodiversity has been created through the careful selection of useful traits by farmers, plant breeders and researchers. Today, modern biotechnology is changing the way agriculture is done (see box: “Biosafety and Agriculture”). 

The use of biodiversity is the key to productive agriculture. Farmers continually require new plant varieties that can produce high yields under different environmental circumstances without large amounts of fertilisers and other agrochemicals. Crop diversity provides farmers and professional plant breeders with options to develop, through selection and breeding, new and more productive crops that are nutritious and resistant to pests and diseases. 

Livestock farmers also need a broad gene pool to draw upon if they are to improve the characteristics of their animals under changing conditions. Traditional breeds, suited to local conditions, survive times of drought and distress better than exotic breeds and, therefore, frequently offer poor farmers better protection against hunger.