This article appears in the December 2023 issue of Front Vision, an educational Chinese-language magazine for kids. It is reproduced here with permission.
Why Does Biodiversity Matter?
by Kathryn Hulick
Tiny ants. Mighty blue whales. Ancient redwood trees. Newborn panda cubs. Millions of different animals, plants, fungi, bacteria, and other living things share planet Earth with us. Biodiversity, short for “biological diversity,” is a term that refers to the variety of life on Earth. That variety is quite astounding. Scientists have named around two million different species but estimate that there are likely five to ten million or even more in total.
However, biodiversity is about more than counting species. Biodiversity is also about how all these lifeforms interact with each other and with their habitats. Thomas Lovejoy, a famous biologist, popularized and may have invented the term biological diversity. “Many think of it as the total number of species, but it is actually more complex than that,” he said in a 2018 interview with the United Nations Foundation. “It’s about the genetic diversity within species, the diversity of habitats, and the large biological units known as biomes.” A biome is a large area with characteristic climate and wildlife, such as a desert, forest, or grassland.
A planet with healthy biodiversity is one where a large number of different species live in a variety of habitats. Biomes are more stable when biodiversity is high. And when conditions do change, species have enough genetic diversity in their populations to allow them to survive and adapt.
But why should it matter to people whether ants or blue whales or pandas have diverse genes, diverse habitats and biomes, or a diverse planet? Lovejoy offered an excellent answer. He said: “Without biological diversity, there is no other life on Earth, including our own. Even though we are often oblivious to it, this diversity of life is what provides clean water, oxygen, and all other things that end up being part of our diet, as well as clothing and shelter. It provides a lot of psychological benefits too, which are not much appreciated.”
Let’s explore all these benefits of biodiversity and learn why the variety of life on Earth is something to celebrate and protect.
Clean Air and Water
People and almost all other animals on Earth need to breathe oxygen. Even fish need oxygen – their gills filter it from the water. Oxygen wasn’t part of Earth’s atmosphere when the planet first formed, though. Around 2.33 billion years ago, a period that scientists call the Great Oxygenation Event began. This major event in Earth’s history happened thanks to something very, very tiny. Cyanobacteria, microscopic life forms that live in the ocean, had figured out how to use sunlight to make their own energy, producing oxygen as a by-product. This is called photosynthesis. Today, cyanobacteria and other types of phytoplankton continue to produce around half of Earth’s oxygen. Land plants and trees produce the other half. If people had to rely only on trees for oxygen, it would take about seven or eight trees per person to produce enough breathable air.
Plants, trees, and phytoplankton also help maintain the climate. They absorb carbon dioxide during photosynthesis. So protecting their biodiversity is especially important as people attempt to respond to climate change. Land plants and trees help regulate temperature, too. Cities with little to no greenery tend to be hotter than surrounding green spaces by 1 to 4 degrees Celsius (1 to 7 degrees Fahrenheit).
Water is yet another essential resource that keeps people and other animals alive. We have fresh, clean water thanks to the water cycle, in which water evaporates or condenses into the air, rains back down, and then travels through the soil, rivers, oceans, glaciers, and groundwater channels. Healthy biodiversity plays several important roles in this cycle. Trees and other plants take up water from the soil and release water vapor into the air from their leaves. Microbes also release water vapor from soil. This process is called transpiration, and is the source of an estimated 40 percent of rainfall over land. Researchers have found that having diverse species of trees in an area leads to a greater amount of transpiration compared with an area that has just one type of tree. Finally, forested areas make water move more slowly through the soil, helping to reduce erosion and lessen the chance of both flooding and droughts.
Diverse populations of trees, plants, and microbes also help clean toxins out of water. For example, the plants in wetlands remove heavy metals, excess nutrients, and particles from water. Many types of fungi, algae, and bacteria perform similar work. Often, one type of microbe removes one type of contaminant. So you need a diverse population of microbes to get clean water. A 2011 study found that the more different algae species there are in a stream, the more total pollutants will be removed from the water. “As the different habitats in a stream are filled by diverse populations of algae, the stream receives more total biofiltration,” said the study author, Bradley J. Cardinale of the University of Michigan. “It’s as if the algae work as a better sponge.”
Food to Eat
The environment also provides all the plants, animals, and seafood that people eat. Of course, most people don’t get their food directly from nature. Farmers grow crops and raise animals in order to produce food. Many farms specialize in just one product, such as rice or beef. So it may seem like biodiversity isn’t necessary in order to feed the world. Why can’t we grow only the foods we want to eat without worrying about surrounding biodiversity? The answer is that these farms are part of the greater environment, and biodiversity ensures that they remain productive and resilient.
Pollination is one important way that biodiversity contributes to agriculture. During pollination, pollen gets transported from the male part of a plant to the female part of the same plant or a different plant. “We need a constant stream of pollinators servicing farms,” says Gretchen Daily, an environmental scientist at Stanford University in California. “About three-quarters of the world’s crops require pollinators to some extent, and that 75% is our most nutritious food – think of all the vitamins and minerals packed into fruits, nuts, and veggies,” she says.
Some plants can pollinate themselves, but the vast majority rely on animal pollinators. Bees are the most well-known kind, and there are over 20,000 different bee species around the world. However, many other creatures work as pollinators, including ants, beetles, butterflies, moths, flies, wasps, birds, and bats. A diverse population of wildlife also helps to control pests on farms. Pests are living things, typically insects or weeds, that devour or ruin a crop. Thankfully, other living things often feed on pests. Daily explains, “We need a constant stream of birds, bats, and other wildlife to help control pests.” For example, ladybugs eat aphids, a pest that feeds on many types of plants. Birds eat many types of insects, and research has shown that having healthy populations of birds near a farm can increase crop growth and yields. These free benefits from nature are called ecosystem services.
A 2019 study of 1,500 agricultural fields around the world looked at pollinator and pest predator biodiversity. The study showed that fields with more variation in their crops, hedges, trees and meadows attracted a greater range of beneficial wildlife and were able to produce more crops as a result. “Our study shows that biodiversity is essential to ensure the provision of ecosystem services to maintain a high and stable agricultural production,” says study author Matteo Dainese, a biologist at Eurac Research in Italy.
Crops also need healthy soil in order to thrive. And healthy soil is packed with a diverse population of microbes, including fungi, bacteria, earthworms, and more. A single teaspoon of soil typically contains around 1 billion lifeforms representing as many as 10,000 different species. In fact, the soil is home to 90% of fungi, 85% of plants, and 50% of the bacteria found on Earth. All these critters help provide nutrients plants need to grow, keep plant diseases at bay, and break down dead organisms. They also help store water and carbon underground. “Organisms in soil play an outweighed impact on the balance of our planet,” says Mark Anthony, an ecologist at the Swiss Federal Institute for Forest, Snow and Landscape Research. “Their biodiversity matters because soil life affects climate change feedbacks, global food security, and even human health.”
Finally, the crops and animals that we raise on farms benefit from biodiversity in their genetics. The more genetically similar crops are, the harder time they will have adapting to changes in the environment. So when a disease, pest, or climate issue threatens a certain type of crop or livestock, scientists often look to ancient, wild, or heirloom varieties for a solution. In a 2022 paper, researchers with the Global Crop Biodiversity Trust in Germany wrote “The resilience and sustainability of food systems depend on crop diversity. It is used by breeders to produce new and better varieties, and by farmers to respond to new challenges.”
Money, Jobs, and New Discoveries
People get clothing, shelter, and many other goods and services from the environment as well. The cotton for clothing and wood for building both come directly from plants. Leather, wool, paper, medicines such as insulin, and many other important products also come from living things. A healthy, biodiverse environment makes it easier to produce these types of products. In fact, $44 trillion of economic value—more than half of global GDP—depends on nature and natural services, according to 2020 report by the World Economic Forum. “As nature declines, the prospects for business success and future prosperity dwindle,” the report says.
Many of the poorest people around the world rely directly on nature for their needs. This is called subsistence living. These populations “live much closer to nature than most people in developed countries, therefore they’re much more vulnerable to the loss of biodiversity,” Rebecca Shaw, chief scientist at WWF, told Global Citizen in 2020. For example, mangrove ecosystems found along sections of the coast of India help sustain healthy fish populations, protect the coast from erosion, and provide wood for building. In one of these mangrove ecosystems, the Sundabarans, 80% of households rely directly on natural resources for food or income. The health of mangrove habitats has declined over several decades due to climate change and other causes, leading to the loss of livelihoods for 62 percent of the workforce in the Sundabarans.
Biodiversity also supports a range of other industries, including tourism. Wildlife expeditions, scuba diving and snorkeling, hiking, and other similar nature-based activities attract a large number of visitors to pristine natural places, bringing income to these regions. Many people also prefer to live or work in or near wild spaces if possible. Numerous studies have shown that time spent in nature is good for people’s mental and physical health. For this reason, wild, biodiverse land can be very valuable.
Biodiversity regularly inspires discoveries in science and medicine. Aspirin is made from willow tree bark. Quinine, one of the earliest treatments for malaria, comes from the bark of the cinchona tree, which is native to South America. The spices turmeric and ginger, which can also be used as medicines, come from plant roots. Scientists today are combing through soil microbes to search for new antibiotics. Antibiotics are medicines that destroy microbes. And soil is home to a huge variety of different microbes that have already evolved a variety of ways to destroy each other. The more biodiversity a soil community contains, the greater the chance that it could inspire a powerful new medicine.
Scientists also study a variety of animal models to learn more about how diseases work and to discover ways that life forms have evolved remarkable abilities such as regeneration, cancer protection, and more. In science and engineering, burrs inspired the invention of Velcro, shark skin inspired better swim suits, and octopus arms inspired new types of robots, to name just a few.
Many species are going extinct before scientists ever learn of their existence. With each extinction, we lose an entire unique biology containing a wealth of information. “Each higher organism is richer in information than a Caravaggio painting, a Bach fugue, or any other great work,” wrote the famous biologist E. O. Wilson in 1985. When an organism disappears, we’ve lost access to this information.
Joy and Appreciation
When you hear that an animal has gone extinct, you’re probably not thinking about what new medicines or technologies it may have helped to inspire. You’re probably also not thinking about how it might have been helpful for agriculture or business or climate control. Simply knowing that a living thing is gone forever is enough to make most people feel a sense of loss and sadness. Extinction marks the death of an entire way of living in the world. That’s tragic on its own, whether or not the organism had anything to do with supporting human life. On the flip side, visiting a biodiverse ecosystem and seeing the many forms life can take often inspires joy and a sense of well-being.
“Human need is a very poor metric for evaluating the existence of living things,” writes ecologist and author Carl Safina in an opinion piece for Yale Environment 360. He argues that the loss of a single species typically has very little to no impact on humanity. Even an extreme reduction in biodiversity likely wouldn’t destroy humanity, though we’d live in a very “grim world,” he writes. The driving reason to protect biodiversity, Safina argues, should be that it’s the right thing to do. He points to the wording of The Endangered Species Act as an example of this type of thinking. “The Endangered Species Act doesn’t claim that our existence depends on the existence of wild species,” he writes. “It says that we, the people, don’t let species go extinct, that this is who we are. It’s not about practicality; it’s about morality.”
Many people aim to protect biodiversity for this reason: they feel it’s morally right to allow living things to continue to live, as much as possible. “I think biodiversity is also just good for human well-being. It makes you feel better about the world when nature is there, when you can see it and enjoy it,” biologist Michael Reed of Tufts says. “I may never see a rhino in my life, but I value that they exist.”
This type of reasoning is at the core of environmental ethics, or the study of the right and wrong ways that people interact with nature. In this field, biodiversity has two types of value. Instrumental value lies in its usefulness – its ability to provide food, materials, income, and so on. For example, a certain flower’s instrumental value may be that it’s a source of medicine. Intrinsic value, on the other hand, is the worth of a living thing regardless of how it may be used. For example, a flower’s beauty or status as a cultural symbol are both examples of intrinsic value.
Most people today believe that a healthy, thriving natural environment deserves to exist. Biodiversity is a part of who we are as humans who evolved on planet Earth. When parts of nature disappear, even very small parts, we lose a part of ourselves.