By Alice Marks
Even though new species are being discovered every day, one in five plants are threatened with extinction, according to the first annual State of the world’s plants, 2016 published by Royal Botanic Gardens, Kew in May 2016. Somewhat unsurprisingly, the largest threats facing these endangered plant species are the conversion of land for agriculture and biological resource use – the deliberate or unintentional consumption of a ‘wild’ species. Indeed, agriculture has been identified as the main threat to 85% of all threatened species, plant and animal, on the International Union for Conservation of Nature (IUCN) Red List. For example, the growth of palm oil plantations has led to significant losses of natural forests and peatlands, with accompanying impacts on biodiversity.
Agricultural biodiversity, defined by Bioversity International as “the variety and variability of animals, plants and micro-organisms that are used directly or indirectly for food and agriculture,” is facing serious decline. According to the Food and Agriculture Organization of the United Nations (FAO) some 75% of genetic diversity has been lost since the 1900s. There are several causes of this loss of diversity, but the main reasons are ease of production and changes in consumer expectations and preferences, leading to an ever greater uniformity in the end product. If the produce is what people want to buy and it’s easy to produce why should it matter if there is less biodiversity? Here are three, of many, reasons why it is of paramount importance:
1.- Genetic diversity is important for an uncertain future
Genetic diversity in agricultural systems may be lost if species go extinct or different varieties of a species fall out of favour. If this happens, genes that are important for resistance to pests or diseases, confer tolerance to changing weather patterns and extreme weather events, or make the crop nutritious, may be lost. Even if these traits are not evident or useful now, the advantage they confer may be valuable for future generations, and may be difficult or impossible to recreate once they are gone. Indeed, work by Bioversity International highlights how the wild relatives of cultivated crops are already becoming increasingly important in the search for traits that farmers can use to improve domesticated varieties through crossbreeding.
Using a wide selection of different species, for example in a crop rotation, can also protect the health of our soils. Each type of plant uses and adds a different mixture of minerals and organic matter to the soil, so using a variety allows soil structure and integrity to be maintained and even improved. As the Montpellier Panel argued in its 2014 report No Ordinary Matter healthy soil brings a multitude of benefits, including greater resilience to extreme weather, better yields, and greater food security.
2.- The enemy of your enemy might be your friend
Sometimes people focus on the crop and forget how much impact the ecosystem it lives in can have. It can be tricky to spot until it’s gone, but the smallest insect or bacteria can have a huge impact on an agro-ecosystem. One example, known as integrated pest management (IPM) is when the natural predator of a pest can help to keep the pest at bay. Farmers can use IPM to their advantage to reduce reliance on pesticides, but the system requires healthy levels of natural biodiversity to ensure there is a pest-predator balance. In Indonesia, for example, IPM is commonly used in rice paddies by the introduction of fish that eat insect pests. Between the introduction of IPM in 1986 and 2001, pesticide use on rice fell by 75% while yields increased by 25%. Because different agro-ecosystems will have different pests and predators, which may change over time, IPM is best employed by experimenting locally, using local natural biodiversity, and being flexible to adapt when conditions vary.
3.- Varied diets for healthy people
There are about 7000 edible plant species in the world, but a staggering 75% of all food comes from just 12 plant and five animal species. According to the World Health Organisation, a good diet is diverse and balanced and includes a variety of fruits, vegetables, legumes, nuts and grains. The heavy reliance on a narrow selection of common crops means that it can be difficult to ensure that an appropriately wide range of nutrients are consumed, so introducing alternatives in each food group could help to combat this. For example, millet varieties account for less than 1% of all grain produced for food but are rich in micronutrients such as B vitamins, calcium, iron, and zinc, as well as similar protein levels to wheat and inferring greater resilience to drought and heat than wheat.
A valuable resource
There is much that can, and is, being done. Agriculture is undoubtedly a major driver of declining biodiversity, but it can also be part of the solution. For example, the use of sustainable agricultural and land management practices has the potential to contribute to the conservation of genetic diversity and sustainable use of biological resources. The urgent need to address this issue is recognised in the Convention on Biological Diversity, and frameworks are under construction to do so, for example under the Sustainable Development Goals (SDGs), particularly under SDG#14 and SDG#15. Let’s hope that these efforts are implemented swiftly to safeguard plenty of biodiversity for the future, because it is amongst the most precious of natural resources that we have.