Biodiversity collapse: the wild relatives of livestock and crops are disappearing

Edwards’s pheasants (Lophura edwardsi) are a wild relative of domesticated chickens.(Photo: DickDaniels, carolinabirds.org, CC BY-SA 3.0, [creativecommons.org/licenses/by-sa/3.0])

Losing wild relatives of domesticated animals seriously threatens the resilience of our food systems, by leaving crops and livestock genetically poorer say Philip McGowan, Friederike Bolam, and Louise Mair

Philip McGowan, Friederike Bolam, and Louise Mair

“Transformative change” is needed to prevent over a million species going extinct, according to a new report on the world’s biodiversity. Based on information gathered over three years from land, freshwater and marine ecosystems, and drawing heavily from the The International Union for Conservation of Nature's Red List of Threatened Species, the report from the Intergovernmental Platform on Biodiversity and Ecosystem Services warns that Earth’s life-support systems may collapse if humanity doesn’t change the way it values and uses nature.

But what does this mean for everyday life? “Biodiversity” – which describes the variety and abundance of species living on Earth – is a term which doesn’t travel far outside debate between scientists and policymakers. The consequences of the biodiversity crisis can seem abstract and difficult for many people to understand, particularly the implications for their own lives.

Think food, though, and the implications become clear

Genetic diversity and food security

Modern livestock breeds and crop species have been bred to be highly productive, which means accentuating particular traits. Chickens have been bred to maintain a uniform size for cost-effective production, while fruit and vegetables have been bred to have thick, juicy flesh. To concentrate these features within livestock and crop populations, plants and animals are bred with ever more genetically similar partners, leaving a shallow and homogeneous gene pool that is a poor defense against disease and environmental change.

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Selective breeding by humans has created livestock species with very low genetic diversity. (Photo: SanduStefan)

Wild relatives of domesticated plants and animals are the ancestral species from which crops and livestock have descended or their near relatives. The pigs we raise for food are descended from wild boar (Sus scrofa) and chickens are descended from red jungle fowl (Gallus gallus) – a species that is widespread in Asia. These wild species are thought to be sufficiently closely related to domestic varieties that they could crossbreed to increase their genetic diversity.

The wild relatives of domesticated species inhabit the rocky and icebound fastness of high mountain ranges, dense tropical forests, and arid deserts. They’ve continued to evolve under natural conditions and so might contain genes that will help food species fight diseases and remain productive in a changing environment. Genetic diversity helps species survive long into the future, by increasing the likelihood that individuals will have helpful genetic quirks, such as immunity to a new disease.

As climate change makes some growing regions hotter and drier, wild relatives of corn that are drought-resistant could be crossbred with farmed varieties to make them more resilient. As new pathogens emerge, wild relatives of cows could crossbreed with cattle to bolster the immune defenses encoded in their DNA.

These ancestral species and wild relatives are, however, not all as common as junglefowl or wild boar. A worryingly large number are little known and highly threatened, or even on the verge of extinction. Baer’s pochard (Aythya baeri) is a critically endangered duck species from South East-Asia that is closely related to the mallard, from which the domestic duck is derived. The Kouprey (Bos sauveli) from central Vietnam is a wild relative of the cow and may even be extinct in the wild.

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Baers pochards are closely related to domesticated ducks.(Photo: DickDaniels, carolinabirds.org, CC BY-SA 3.0 [creativecommons.org/licenses/by-sa/3.0])

Humans are relying on a narrowing base of species for food, using more and more commercially-bred livestock and crops while losing the wild relatives – the reservoir of genetic diversity. These genetic resources may become increasingly important for feeding some nine billion people by 2050, in a world shaped by climate change and all the knock-on effects this will have for agriculture.

Protecting wild relatives

The status of wild relatives is, overall, worse than for birds and mammals generally. Whereas 25 percent of all mammal species are considered threatened with extinction, more than half of mammals that are wild relatives of domesticated mammals are threatened. The figures for birds, while overall less threatened, show a similar pattern. Some 13 percent of all birds are threatened, compared with 31 percent of birds which are wild relatives of domesticated species like chickens and turkeys.

It’s perhaps unsurprising given that these species, like their intensively farmed relatives, are large-bodied and so once caught or killed provide a good source of nourishing food. That’s certainly the case for Edwards’s pheasant (Lophura edwardsi) – a critically endangered species which belongs to the same subfamily as chickens, native to South East-Asia and widely snared. A further 30 species are considered endangered, such as the Lowland Anoa (Bubalus depressicornis), a close relative of the river buffalo and native to Indonesia.

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Lowland anoas are closely related to river buffalos – a common farm animal in Asia.(Photo: Attis1979, CC BY-SA 3.0, [creativecommons.org/licenses/by-sa/3.0])

Losing these wild relatives of domesticated animals seriously threatens the resilience of our food systems, by leaving crops and livestock genetically poorer. The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services report highlights this threat. Countries will agree targets for protecting biodiversity in 2020 and the wild relatives of domesticated species should be chief among them.

We really do need a transformation in our relationship with nature, and this will have to include a serious change in our diets and how food is produced. We will need wild relatives of important food species to ensure that genetic diversity can enhance food security in an increasingly uncertain future.

Philip McGowan is a Senior Lecturer in Biodiversity and Conservation, Newcastle University. Phil has worked for many years in international species conservation. He previously concentrated on highly threatened species in Asia, Africa and South America with particular areas of study in India, Nepal, China and Djibouti. This work concentrated on Galliformes, an order of birds that includes turkeys, pheasants, grouse and the wild ancestor of the chicken. 25% of Galliformes are at risk of extinction, typically because of people hunting them for food. He now seeks to understand what research can help inform policy and how to best communicate it.

Friederike Bolam is a Post-doctoral Research Associate in Biodiversity Policy, Newcastle University. Her work relates to global biodiversity policy, including the Convention on Biological Diversity’s Aichi Targets and the UN’s Sustainable Development Goals. She is interested in how we can accelerate progress towards species conservation, whilst also accounting for other societal priorities such as food security. For her Ph.D., Rike studied how to make the most of available evidence for informing conservation decision-making. She used evidence synthesis methods, open-source data, and Machine Learning tools for investigating the use of Value of Information in conservation. Rike also holds a UK bird ringing license and has extensive experience in monitoring passerines and raptors.

Louise Mair is a Research Associate in Biodiversity Conservation and Policy, Newcastle University. Her research focuses on Aichi Biodiversity Target 12 of the Convention on Biological Diversity's Strategic Plan for Biodiversity 2011-2020, which aims to end extinctions and reverse declines of species. She looks to understand why global progress towards this target has been limited, what the challenges in achieving Target 12 are, and how to develop a decision-support approach that will assist countries in conserving threatened species. Louise has a background in macro-ecology, with a focus on patterns and drivers of species distribution changes in response to climate change and land use. She is particularly interested in the application of citizen science data (CSD) to address ecological questions.

Note: originally published at theconversation.com; re-published with permission.

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