Biodiversity is the immense variety we see in all life on earth. As living things adapt to their environment and evolve over time, more and more variation emerges. Scientists estimate that at least 8.7 million unique species of animals, plants, fungi, and other organisms exist on Earth, along with countless varieties of bacteria.1 Each of these species is adapted to play a special role in its immediate environment, and this variety ensures that ecosystems function properly and remain in balance. In agriculture, biodiversity is also useful for humans: genetic diversity in crops and livestock helps guard our food supply against disease and other threats. Unfortunately, industrial agriculture prioritizes consistency and productivity over biodiversity, and relies on only a few varieties of plants and animals. Treating crops and livestock like parts on an assembly line rather than unique players in a dynamic system threatens both wild species and has serious implications for our own domesticated food supply. Sustainable agriculture embraces biodiversity by minimizing its impact on wild ecosystems and incorporating numerous plant and animal varieties into complex, on-farm ecosystems.
Biodiversity is what makes every environment on earth unique. While we see biodiversity in the breathtaking shapes and colors of the natural world, it starts with genetics. DNA is intrinsic to all living things, and that genetic code evolves over time. Different genes correspond to different traits in the organism. We can see many of these traits with our own eyes, but others are less obvious, like genes for stress and disease resistance. This genetic diversity is vital to ensuring that species can survive the ever-changing conditions their environment presents.
Biodiversity has been important to agriculture since the beginning. Long ago, humans harnessed and steered genetic diversity by domesticating edible plants and animals. Even without understanding genetics, the earliest farmers did this simply by choosing to raise plants that produced large, edible seeds. As these domesticated plants spread across the world, they evolved their own variations. Like their wild counterparts, crops also depend on genetic diversity for traits that help them resist disease and stay productive under stress. Genetic variation within crops also brings us the huge variety of foods we enjoy. Biodiversity within livestock is important for the same reasons, and there are thousands of heritage breeds of pigs, cattle, poultry and other animals that are beautiful, unique and specially adapted to their environments.
Maintaining biodiversity in the wild and in crops has benefits on the farm. Even though they are managed by humans, farms are still ecosystems. The plants, soil, and animals all depend on one another for nutrients and habitat. In a functional agro-ecosystem, healthy soil microbes provide nutrients to plants, the root systems of which hold the soil in place. Plants provide food and habitat to beneficial insects and birds that pollinate them and manage pests. Livestock can recycle leftover parts of crops and provide natural fertilizer to fields and pasture through manure. Agroecosystems depend on diversity to stay in balance, and industrial agriculture disturbs this.
Agriculture relies on natural processes and living things to create food, but often changes the environment around it. While farms can be managed in ways that minimize their damage to the environment around them, industrial agriculture’s focus on productivity means that too many farms are disruptive to wild species both near and far. When environments are too altered or polluted by industrialized agriculture, vulnerable species may lose their habitats and even go extinct, harming biodiversity.
Whether it’s growing fruits and vegetables, grains or animals, agriculture takes up space. Prime farmland — land with good soil and water access — is a limited resource. These same areas often support rich wild ecosystems like prairies and forests; converting these areas into farms eliminates much of that wild biodiversity. Unfortunately, agriculture’s continually expanding footprint places these sensitive and important wild areas at risk of destruction. This process of bringing more wild land into agriculture is called extensification.
Agricultural extensification isn’t new. In the United States, grassland ecosystems like the tallgrass prairie once covered nearly 170 million acres, and supported nearly as many plant and animal species as tropical rainforests. Through managed fires and other tactics, indigenous peoples helped maintain a rich, biodiverse environment where bison and other animals thrived.2 But as settlers pushed native peoples off their lands, this changed: the deep roots of grasses made the soil rich in organic matter, which meant it was ideal for plowing into productive farmland. After 150 years of agricultural development, however, the tallgrass prairies have been reduced to only one percent of their former range, often preserved in narrow strips between fields or along railroads.3
The loss of the prairies contributed to the dramatic decline in the species that depended on them, including the bison — which settlers hunted nearly to extinction, destroying indigenous ways of life — and this loss continues today.4 Even though farmland in the United States is shrinking overall, there are many regions where wild land is still being plowed up: 2.5 million acres of grassland were converted to new cropland between 2015 and 2016.5 The continued expansion of farmland onto American grasslands has serious consequences: for example, populations of pollinators like monarchs have fallen by 70 percent in recent decades.6 A diverse array of pollinators is important, since native pollinators will visit more types of plants than European honeybees alone — this keeps native plant populations healthy, in addition to boosting productivity on the farm.7 Even when farmland is taken out of cultivation and replanted with wild species, the number of plant species an area supports takes decades to recover. This in turn limits the number of insects, birds and other animals that the environment can support.
One of the most dramatic examples of biodiversity loss through extensification is the ongoing destruction of the tropical rainforest. Rainforests are hotspots of biodiversity, with the Amazon alone containing nearly 25 percent of all living terrestrial species.8 80 percent of deforestation worldwide is attributed to the expanding footprint of agriculture.9 While “slash and burn” agriculture — where farmers cut and burn small areas of forest, and farm them for a few seasons before moving on to another plot — is often blamed for this deforestation, these approaches actually do less harm than the industrially scaled agriculture, which is permanently replacing forest. Growing crops like soy and oil palms or raising cattle offers farmers more income than preserving forest, which drives the permanent deforestation of over 100,000 square miles a year, an area about the size of the UK.1011
Industrial agriculture’s impacts are not limited to habitat destruction through its expanding footprint: its reliance on heavy chemicals to create giant stands of single crops has serious consequences for plant, animal and microorganism biodiversity.
A number of innovations allowed for widespread intensification of agriculture throughout the twentieth century. Widespread adoption of steel plows, hybrid seeds, GMOs, chemical fertilizers and pesticides helped farmers produce more food per acre than ever before. More recently, the adoption of genetically modified seeds helped to increase yields even further. This productivity comes at a great cost, however. Wide fields of a single crop (called monocultures) provide simplicity for farmers and a steady supply of feed to factory farms, but they are biodiversity deserts. Maintaining monocultures requires intense chemical inputs that reduce the abundance of wild species both on and off the farm.
Pesticides and herbicides are designed to eliminate pests that can harm or compete with crops, but these chemicals can harm plants and animals outside of farm fields. Herbicide overuse and intense soil disturbance both impact plant diversity on and around farms — researchers studying plant communities around intensively managed farms found they had fewer species than their organic counterparts 12 Reductions in plant diversity can have effects on the animals that depend on them; the widespread adoption and increased use of the herbicide glyphosate in the US, for example, has significantly reduced wild plant diversity in and around farmland, which in turn has harmed populations of beneficial insects like monarch butterflies that rely on plants like milkweed.13
While herbicides can disrupt food webs (including the animals within them), insecticides can harm other animals more directly. Pesticides like neonicotinoids harm bees and other insects, limiting colony growth and impairing communication,14 which can seriously limit their ability to pollinate crops and other plants. Some insecticides are also toxic to fish, amphibians, and birds; agricultural pollution is the main threat to many species around the world.15
Industrial agriculture also wreaks havoc on biodiversity within soil. Communities of insects and other invertebrates have their habitats disturbed when farmers plow up soil, interrupting their ability to recycle dead plants into the rich, stable organic carbon that makes soils fertile.16 Likewise, chemical use impairs the microorganisms involved in this process: scientists have found fewer species of beneficial bacteria and fungi in soils where chemical fertilizers and pesticides are used.17 Ultimately, these soils become less biodiverse and less healthy for crops. Such changes also contribute to climate change: soil stores over 1.6 trillion tons of carbon dioxide worldwide, but highly disturbed soils with low biodiversity quickly lose that carbon to waterways and the atmosphere.18
Chemical use can also impact ecosystems far from the farm. Nitrogen fertilizers, which help speed plant growth, can run off into waterways where they accumulate and cause uncontrolled algae growth (called an algae bloom), blocking light to the rest of the water. When the algae die, their decomposition uses all the available oxygen in the water, creating “dead zones,” which are uninhabitable for fish and other aquatic life. This process, called eutrophication, can happen in both fresh and saltwater. Excess manure from factory farms is rich in the same nutrients, and also contributes to eutrophication.
One of the most well-known examples of eutrophication — a 7,829 square mile dead zone in the Gulf of Mexico — is the result of fertilizers from farms across the Midwest draining into the Mississippi River.19 While some fish are able to find new habitat, these oxygen-free zones are fatal to animals that live on or in the seabed: these areas may have less than half the species than higher-oxygen sites.20 Scientists studying dead zones in lakes found that eutrophication reduces the available habitat for aquatic life and forces competition between many species in small areas, ultimately leading to the lake’s loss of biodiversity.21
On a global scale, industrial agriculture threatens biodiversity, by being a major contributor to climate change. Agriculture-related emissions, mainly from chemical fertilizers and factory-farmed livestock, make up more than 20 percent of all greenhouse gas emissions annually.22 Climate change is one of the most serious threats to biodiversity, and affects even remote areas scarcely touched by humans. Warming temperatures already have a demonstrated impact on the way migratory birds and other animals reproduce, and extreme weather cycles can completely change the makeup of plant and soil communities.23 Overall, the pressures of a warming climate favor adaptable invasive species that could overtake millions of highly specialized plants, animals, and microorganisms. Scientists modeling these changes say that climate change-related biodiversity loss could be one of the largest mass extinctions in the history of the Earth.24
While there are thousands of potentially edible plant species on earth, the FAO estimates that 75 percent of the food on earth currently comes from only 12 plants and animals that we raise on a wide scale.25 Many of these foods are common because of their consistency and reliability, but they’ve displaced countless varieties of grains, fruits, vegetables and livestock. Because many of these crop varieties aren’t found in nature, they go extinct when they are no longer grown. Biodiversity in domesticated crops and livestock is important because it ensures there is a large gene pool for traits like disease resistance; growing only a few varieties of plants makes our food supply vulnerable to threats like climate change and disease. Preserving wild relatives of crop plants, which are also threatened by industrial agriculture and other development, is important for the same reason: wild populations are a store of potentially useful genes that have been bred out of their cultivated relatives.26 There’s also a human dimension to preserving biodiversity in crops and livestock, since they become unique foods that are essential to cultures, cuisines and diets around the world.
The widespread loss of biodiversity in agriculture is an example of what biologists call genetic erosion. Genetic erosion can happen when entire species are lost: for example, in ancient North America, when corn (a species native to Central America) was introduced, it began replacing a number of domesticated plants.27 Genetic erosion can also happen within species: of the 400,00 varieties of rice that once existed in India, only 30,000 remain today.28 This erosion happens over time. For most crops, thousands of local varieties, called landraces, were gradually narrowed into a smaller number of varieties by commercial breeding. The advent of hybridized seeds and genetic modification in the twentieth century accelerated this process. Control over the seed industry is held by a small number of companies, thereby limiting farmers’ choices about what they can plant, and driving diversity down even further: the four largest seed companies in the United States control 85 percent of the market, and most sales are of a few varieties of genetically modified corn and soy.29
While modern crop varieties offer consistency and high yields, many depend on heavy chemical use to be productive, and need to be grown alone in a monoculture for best results. Monocultured varieties of crops were common during what historians call the Green Revolution: in the latter half of the twentieth century, modern varieties of wheat and rice — which propagated year after year — crowded out more diverse rotations of other crops, like millets, legumes and root crops.30 This transition helped provide food for a growing population, but it also entirely displaced many crop varieties, and created an agricultural landscape dominated by chemical-dependent monocultures.
Monocultures may offer consistency to farmers and the food industry, but they pose a risk to food security. In the early twentieth century, most of the world’s banana production came from a single variety: the Gros Michel. In the 1950s, an outbreak of Panama Disease (a soil-dwelling fungus) nearly wiped out the Gros Michel, which was especially susceptible to it. The Central American banana industry avoided complete collapse by adopting another variety, the Cavendish banana, which was resistant to the fungus, but also smaller and less flavorful.31
Biodiversity saved the banana industry 70 years ago, but the industry has repeated the mistake: the Cavendish banana makes up 99 percent of all banana exports today. Now, as another strain of Panama Disease that can attack the Cavendish Banana threatens to overtake the industry, researchers are turning to other, less common banana varieties to try and breed more resistant crops.32 Apples, wheat and other crops face similar threats from disease, and neglected and rare varieties of these crops may hold the answer for their preservation.3334
By destroying soil carbon stocks and relying on greenhouse gas-intensive fertilizers, low biodiversity systems in agriculture — both crop monocultures and factory farms — accelerate climate change. In turn, climate change poses threats to agriculture: crops will need to survive in drier, saltier soils and withstand more frequent floods, and livestock will need to adapt to extreme weather conditions. These traits are found in varieties of crops and livestock around the world, but many of them have been mostly displaced by uniform varieties that are best suited to industrial agriculture. Ultimately, adapting agriculture to the challenges of climate change will require preserving and drawing from the same pool of genetic resources that industrial breeding has steadily whittled down for decades.
Food is one of the defining aspects of culture, and every cuisine on earth relies on unique crops and livestock. Sadly, many varieties are being replaced by commercially-bred crops often imported from other countries. While possibly more productive in chemical-intensive monocultures, the new crops tend to displace culturally important varieties.
When local varieties of crops disappear, this can compromise food sovereignty — the ability of a community to access culturally appropriate food at a fair price.35 The replacement of local crop varieties with commercially bred imports increases farmers’ dependence on chemical use and purchased seeds (rather than saved ones). This ultimately funnels wealth from small farmers worldwide into the hands of large agribusinesses. Many farmers are forced off their land as costs rise, even when they choose to continue growing traditional crops; the rush to cash in on lucrative new varieties drives up demand for farmland, making traditional farms unable to compete.36 This further limits their ability to grow culturally appropriate foods, and contributes to the disappearance of biodiversity in crops and livestock.37
Given that agriculture’s expanding footprint is responsible for so much habitat loss, preventing wild lands from being converted into farmland is critical to maintaining biodiversity. By embracing both traditional knowledge and new research, farmers and scientists are producing food in a way that harnesses biodiversity to make the most of what nature provides. This approach is called agroecology, and is a core component of regenerative agriculture, which builds up natural resources like healthy soil and water rather than using them up.38
While embracing agroecology is a revolutionary shift away from industrial farming, it’s nothing new: these practices are often adapted from the practices of indigenous peoples worldwide, who have created complex agroecological systems that exist in balance with nature. Preserving and reviving these indigenous traditions can make agriculture around the world more sustainable and help preserve biodiversity.39 The fact that 80 percent of the world’s biodiversity is preserved on lands that are managed by indigenous people is a testament to agroecology’s potential.40
A critical part of regenerative agriculture is building a productive agroecosystem that isn’t reliant on chemicals. Harnessing biodiversity is key to this, and breaking up big, monocultured fields with just a few more species can bring great benefits to both crops and wildlife. Creating productive agroecosystems means — following the example of indigenous peoples’ longstanding traditions — selecting plants that will benefit each other rather than relying on chemical inputs. For example, legumes like beans and lentils add vital nitrogen into the soil, which other plants need to grow. This has benefits that stretch beyond the farm: incorporating legumes into diverse fields not only provides crops with natural fertilizer, it avoids all of the greenhouse gas emissions associated with using synthetic fertilizers, and helps curb global warming.41 Other plants can provide valuable shade or support — like the classic “three sisters” system of Native American agriculture. Mixing plants together like this is called intercropping, and this can help lower the environmental footprint of a farm. Even without chemical inputs, farmers can see enormous benefits when they grow crops in intercropped systems: experiments with corn, beans, wheat, bananas and other crops have all shown that such systems can be more productive than their industrial counterparts while enhancing biodiversity on the farm and making a varied, rich habitat for wildlife.42
Another technique that creates biodiverse agroecosystems is agroforestry (also a traditional, indigenous method of land management), which works woody plants into crops and pastures. This can include fruit or nut trees, or shrubs that are cut and harvested for biofuel. Tree roots also enhance soil fertility by adding carbon and preventing erosion; compared to a traditional monoculture, some agroforestry systems see a 40 percent increase in yields of many crops.43 Models suggest that existing agroforestry plantations will remove more than 2 billion tons of CO2 from the air over the next 50 years, and expansion of these systems could be a valuable strategy in combating climate change.44
Livestock are often important players in agroecological systems. By eating residues of harvested crops and other materials that might go to waste, animals in an agroecological system are less resource-demanding than their counterparts on a feedlot.45 Animal manure creates an efficient natural fertilizer that encourages rich soil and high productivity in plants. Indigenous peoples around the world have used grazing livestock in this way to manage grasslands to maximize productivity, and adopting these systems today can benefit biodiversity on wild grasslands.46 Careful grazing also boosts biodiversity on the farm: on well-managed pasture, grazing animals can clear patches of grass and turn up soil with their hooves, creating an ideal environment for different plants to thrive.
Preserving genetic diversity in livestock is important for the same reasons that it’s important to preserve diversity in crops: traits like stress and heat tolerance are vital, and help animals adapt to a wide variety of places beyond the controlled environment of a factory farm. Diverse livestock breeds also have unique behaviors that help maintain a varied agroecosystem; different kinds of livestock have different grazing patterns, for example, and therefore an array of species and breeds can foster immense biodiversity in a pasture. Adding animals to an agroecological system can also become another income stream for farmers, especially in low income areas; this financial boost is critical to maintaining more sustainable farms.47
Biodiverse agroecosystems also create rich, low-chemical habitats where wild organisms can thrive. Surveys of biodiversity in agriculture have found that birds, invertebrates and other small animals are more abundant and more diverse when agroecosystems incorporate a variety of crops.48 Many of these species can provide a wide variety of benefits to crops. Diverse agroecosystems can see up to 50 percent reduction in pests and twice as much pollinator activity compared to monocultures where beneficial insects are excluded.49 One system that harnesses wild biodiversity on the farm incorporates strips of native prairie planting into crop fields. This improves soil and attracts pollinators while providing some hay for livestock. Farms with prairie strips can foster insect and bird populations that are three times more diverse than farms without them, and see dramatic reductions in fertilizer runoff and soil loss, lightening their footprint.50
Fostering communities of beneficial wild animals is a key part of integrated pest management, or IPM. Integrated pest management treats pesticides as the option of last resort for protecting crops, and instead focuses on using beneficial relationships between insects and plants as a first line of defense. Although building a functional and robust agroecosystem takes effort, these approaches generally see lower levels of damaging pests than conventional systems, where pesticides indiscriminately kill off beneficial insects along the way.51 Like other aspects of agroecology, using beneficial plants and insects to control pests is a core feature of indigenous agricultural practices worldwide, and the push for sustainable agricultural development is putting this traditional, local knowledge at the center of training programs around the world.52
In addition to using the benefits of species diversity to create and sustain productive and healthy agroecosystems, it’s important to preserve the countless varieties of crops and livestock in cultivation. This includes seed and gene banks, but also requires the participation of farmers, gardeners, and eaters around the globe.
Indigenous communities worldwide are important protectors of agricultural biodiversity. Sadly, these genetic resources are often taken from the communities that preserved them, and then privatized. A vital part of maintaining biodiversity is recognizing these communities for their work and appropriately compensating them. Projects should allow smallholder farmers to lead the way in preserving and cataloging biodiversity while also giving them a platform to benefit: the Potato Park, for example, pays Andean farmers to catalog and develop biodiversity, and doubled local incomes while expanding crop diversity.53 Partnerships between indigenous groups, governments and other organizations like the Native American Food Sovereignty Alliance help to reintroduce preserved crop varieties while creating a more formal platform for indigenous knowledge within scientific institutions.54
Other seed preservation projects work by collecting seeds and placing them in long-term storage. Organizations like the Crop Trust preserve thousands of crop varieties, while studying their genetic makeup and keeping records about their cultural heritage. One of the largest seed banks in the world, the Svalbard Global Seed Vault in Norway, holds over a million samples from around the planet in cold storage.55 Smaller networks of seed banks are also vital, and help preserve local landraces and varieties.
Livestock preservation is equally important. It is possible to preserve sperm and egg cells from animals in a way that mirrors seed banks for crops, and the FAO has already established regional gene banks for animals in Africa, Asia and Latin America.56 However, these gene banks can be harder to maintain, as they require expensive equipment and reliable power, but preserving live animals in collections (and on farms) is another viable approach to livestock conservation. Organizations like the Livestock Conservancy do this by helping network people who raise heritage breeds, providing knowledge on how to raise them and helping them maintain a large breeding pool in multiple areas.57
Keeping crop and livestock varieties on farms and in gardens is equally important. The Slow Food movement approaches biodiversity through an “eat it to save it” approach — by promoting unique regional foods, chefs and activists create a new market for farmers who are encouraged to keep growing those crops.58 In addition to keeping seed banks and large collections of living plants across the country, groups like the Seed Savers Exchange foster connections among individual gardeners that are preserving more than 25,000 heirloom vegetables and other crops in their own gardens.59 Expanding the network of growers who keep rare varieties ensures protection from loss.
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Previous page photo by Maggie Tauranac/Staff.