Three reasons to protect agricultural biodiversity

By Alice Marks, @alicemarks0

Durum wheat variety, Ethiopia. Credit: Bioversity International

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

Several different varieties of quinoa grown in Peru. Credit, FAO

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.

Four ways with pesticides

Pesticides, substances designed to prevent, destroy or mitigate any pest, are beneficial in many ways. They protect crops from infestation, allowing for higher and more stable yields, and they protect humans from insect attack, crucial in the fight against insect-transmitted diseases such as malaria. But they also pose serious threats to the environment and to human health. In response to the concerns over the impact of pesticides on bee populations, for example, the European Union, earlier this year, issued a partial ban on neonicotinoids.

A new special issue of Science, The Pesticide Paradox, through a series of papers, explores the benefits and impacts of pesticides and discusses what more can be done to track pesticide use, reduce our reliance and its impact, and find alternatives.

Track their use and evaluate their impacts

Understanding how and where pesticides are used and what hazards they pose is the first step to minimising their impact. For example, pesticide degradation and its effect on the landscape is little understood, as are the impacts of pesticides on non-target organisms and communities, and on human health and development. One paper shows the alarming impact exposure to pesticides in early life can have on brain development – reducing IQ and causing ADHD-like behavioural problems.

Verger and Boobis in their article, Reevaluate Pesticides for Food Security and Safety, discuss the use and sale of generic versions of pesticides, which account for some 30% of total pesticide sales. As the original producer has little impetus to assess the usage and hazards, these pesticides, despite being more affordable to farmers in developing countries, may not meet internationally accepted criteria. Authors describe how these generic pesticides can be monitored.

Reduce their use

The next obvious step is to minimise their use. For some farmers, prudent use of pesticides can boost crop production but for others, particularly under intensive farming, pesticides are over-used, sometimes creating new pest problems or pest resistance. For example, in Indonesia where the Brown Panthopper became a serious pest of rice, pesticides were found to be ineffective because they also killed parasites and wolf spiders, natural enemies of the Brown Planthopper. Use of Integrated Pest Management, a combination of pest control techniques, reduced the use of pesticides while at the same time raising rice yields. More holistic methods of pest control, however, can be knowledge-intensive. In Vietnam, large-scale experiments and use of radio have shown farmers how to use pesticides more judiciously to increase their profits.

Antiobiotic use on organic apples and pears

Think organic farming doesn’t use harmful compounds, think again. As the expiry date for the use of the antibiotics, Streptomycin and Oxytetracycline, on organic apple and pear farming in the US approaches, much debate has arisen over the standards for organic farming and food labelling.

Apples and pears are subject to an infection called Fire Blight, which can devastate entire orchards For that reason organic farmers have received an exemption allowing them to spray certain antibiotics to tackle this disease. In 2002 when the US Department of Agriculture’s national organic labelling standards went into effect the two antibiotics were included in a list of ‘allowed’ compounds subject to periodic review. This exemption is set to expire in October 2014, which supposedly allowed time to develop new, non-antibiotic, methods of control. But as 2014 approaches and a viable alternative is still lacking, some groups are battling for an extension on this expiry date.

Last week the National Organic Standards Board met to discuss a petition from organic farmers to extend the exemption. They rejected this petition and use of the antibiotic Oxytetracyline will not be allowed beyond the existing expiration date. In six months’ time the Board will meet again to discuss the use of Streptomycin.

50 Years After Silent Spring

On the fiftieth anniversary of Rachel Carson’s Silent Spring, Guardian writer Leo Hickman, opened up discussion about the book’s impact on the world.  The comments that follow the article raise several questions:

• While synthetic pesticides are manufactured to be more targeted and less harmful to the environment they are also used prolifically and use is growing. So in terms of the chemicals we pump into the environment are we better off now or back then, in 1962 when the book was first published?
• This leads to a second question: given our knowledge of the harm pesticides and other chemicals can have on the environment and human health, for example the recent evidence of the link between pesticides and declines in bee numbers, and, in some cases, their limited time period of effectiveness on pests, are we even more irresponsible to be continuing to use such products in this day and age?
• A clear message from the book is that if the human population itself is to be sustainable we must co-exist with nature in the same way that environmentalism and economics must learn to co-exist or combine. But are we any nearer to reaching this and can the two fields find the middle ground?
• Finally, how can two goals seemingly at odds with one another – feeding the world’s chronically hungry, 98% of which are in developing countries and 80% of which are smallholder farmers often facing pest, disease and soil fertility challenges, and ensuring the planet’s sustainability – be resolved?

We’d love to hear your thoughts on these questions, to continue the discussion and to ensure we make progress within the next 50 years.

New Research Shows the Damaging Impacts of Pesticides on Bees

While modern synthetic pesticides are developed to reduce impacts on non-target organisms, two recent papers published in Science have brought to light new evidence of the damaging effects of pesticides on bee colonies.

Both papers investigated the impact of the use of neonicotinoid pesticides on bees. When sprayed on crops such as oilseed rape, maize and sunflower, these pesticides spread throughout plant tissues including into nectar and pollen, and as such are directly available to bees, although in trace amounts.

The first paper published in March 2012, found that bumblebee colonies exposed to field-realistic levels of the neonicotinoid imidacloprid suffered reduced growth rates and an 85% reduction in the production of queen bees.