Taking stock of the staggering diversity of life on Earth
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Fall 2002 Feature Opener - Biodiversity

Earth is teeming with life, from the biggest blue whales and redwoods to the tiniest bacteria and fungi, all bound together by a maze of interactions. Earth has so many species in so many places—be it in a square inch of soil or along a thousand-mile migration route—no one is even sure how many there are.

Biodiversity refers to the spectacular variety of living species on Earth. To date, scientists have documented about 2 million species with perhaps 10 million more still unknown. These include charismatic bears, birds and wolves—as well as lesser-known algae, insects and other invertebrates (species without spines). Regarding the tremendous value of the lesser-known organisms, ecologist E.O. Wilson, often called the father of biodiversity and a Defenders’ science advisor, wrote: “These least understood minions are the foundation of the living world. They are the little things that run the Earth.”

We do know, however, that Earth is now losing species at a rate 1,000 times higher than we’ve ever seen. We’re on the edge of a mass extinction event, something that’s happened five times before but never because of us.

Humans are driving this acceleration—from poaching to pollution and habitat loss. Nature is resilient, but as extinction escalates and we lose biodiversity, we risk shutting down the very processes that allow nature to evolve, adapt and regenerate in response to changes. Once species are lost, they are lost forever—there are no do-overs.

“So goes nature, so goes us,” says Jamie Rappaport Clark, Defenders of Wildlife’s president and CEO. “Loss of biodiversity is our single greatest threat. Biodiversity is the fabric that holds all life together. And yet it faces unprecedented threats and decline with nearly 1 million species at risk of extinction today. We are rapidly running out of time.”

Food for Thought

About 75% of our food supply comes from just 12 plant species, and 90% of global livestock production comes from 15 species of mammals, fish and birds. Without hundreds of thousands of other species working behind the scenes, our food supply would collapse.

A wide range of wildlife makes agriculture possible, including bees, bats, birds, ladybugs, spiders, toads and wasps, to name a few. Approximately 80% of crops depend on insect pollinators, with bees alone responsible for boosting U.S. crop revenue by more than $15 billion per year. And wildlife doesn’t just protect and pollinate food. Three billion people rely on daily protein from wild-caught fish, including many species that depend on healthy coral reefs. 

Nature Heals

Biodiversity is strongly linked to human health. Top of mind is the global COVID-19 pandemic that continues to wreak havoc on human health and economies worldwide. Biodiversity supports healthy ecosystems to naturally regulate disease and protect human health. But as we siphon off more natural areas for uncontrolled development and keep wildlife and domestic livestock in stressful and unsanitary conditions, the barriers between humans and animals carrying potentially deadly diseases become increasingly thin.

Many species are essential contributors to our natural pharmacy as well. Medical discoveries often begin with research on the biology of plants, animals, fungi or bacteria. In fact, about half of modern drugs are developed from nature-based products. For example, the asthma drug theophylline comes from cacao trees, and about 70% of plants with cancer-fighting properties only occur in rain forests—biodiversity hotspots that contain half of all known species. In the forests of North America, the eastern red cedar produces a compound that is known to fight antibiotic-resistant bacteria. Many more natural remedies are likely out there, but without protection and proper management their sources could go extinct before we discover them.

And then there’s the healing power of nature itself. Spending time outdoors is associated with better health, including lower risks of diseases like type II diabetes, cardiovascular diseases, high blood pressure, obesity and mental disorders. It also improves the cognitive development of children. In this time of social distancing and COVID-19, we’re turning to nature for solace and realizing that outdoor spaces, parks and wildlife areas are essential to the health and well-being of everyone.

“Signals abound that the loss of life’s diversity endangers not just the body but the spirit,” wrote Wilson. “If just that much is true, the changes occurring now will visit harm on all the generations to come.”

At Your Service

Food and medicine are just two of many “ecosystem services”—the contributions of ecosystems to human well-being—that people receive from biodiversity. For example, fruit-eating tropical tortoises and spider monkeys help to maintain a stable climate by dispersing seeds of the dense-hardwood trees that are most effective at removing carbon dioxide from the atmosphere. We don’t often think about how tree roots protect us from storms by soaking up water and preventing landslides or how coral reefs serve not only as nurseries and feeding grounds for marine species but also provide critical protection from coastal storms and flooding.

Even the soil beneath our feet is rich with biodiversity. It encompasses tiny creatures like nematodes, tardigrades, mites, springtails, ants, termites and earthworms that regulate ecosystem processes, such as carbon sequestration, greenhouse gas emissions and the uptake of nutrients by plants. They detoxify polluted soils, suppress soil-borne diseases and regulate nitrogen, which, just like oxygen, is essential to life.

Above ground, the busywork of other tiny creatures goes largely unnoticed, as insects eat other insects widely recognized as pests, decompose waste and become food for birds, amphibians, bats and more. The majority of flowering plants are pollinated by insects—and they’re a diverse group, including bees (more than 20,000 different species), flies, butterflies, moths, wasps and beetles. Some insects are particularly evolved to their niche. For example, each of the 900-plus fig tree species depends on its own obligatory wasp species for pollination, which in turn depends on the specific tree species for a place to breed.

Some estimate the value of these ecological services to be at least $125 trillion a year. As an example of cost efficiency, New York City opted to invest $2 billion in natural water filtration in the 1990s to supply its residents with clean water. Human-engineered solutions, like filtration plants, would have cost $10 billion plus operating costs. 

Biodiversity is nature’s insurance policy. Having a richness and diversity of species allows other plants and animals to step in—should others disappear—to fill an array of different ecological niches and respond and adapt to disturbances like extreme fires and floods. Safeguarding as many biologically rich places as we can, as soon as we can, will help our natural landscapes survive in the event of catastrophic impacts or significant environmental changes.

Beauty of the Beasts

While there are many well-documented practical reasons to preserve biodiversity, let’s not forget the spectacular beauty of the diversity of life on Earth. More than 71 million Americans participate in and enjoy wildlife-watching each year, and the numbers continue to rise. There’s something magical and rejuvenating about wildlife watching—a deer in the meadow, a bird soaring overhead, a seal popping up by your kayak—that freezes time and reawakens a sense of wonder. Few things are more exciting than seeing an animal in the wild.

Most of us yearn to “get away” to the mountains, oceans, rivers, deserts and forests that call to us. We seek out birdwatching, wildlife viewing, hiking, nature photography and other outdoor activities to stimulate and revitalize us. Thankfully, natural areas abound even in urban areas and offer an important resource for resting and restoration.

Troubled Times

Even though the importance of healthy wildlife populations is widely discussed and access to nature is encouraged and celebrated, many often aren’t aware of the rapid decline in biodiversity and humanity’s role in it. In just the last 50 years, our ecological footprint has increased by about 190%. Our overexploitation of species and escalated habitat destruction—all propelled by runaway consumption—are the main drivers of biodiversity loss. In the U.S. alone, every 30 seconds a football field-size expanse of land disappears to roads, houses, pipelines and other development.

The oceans tell a similar story. More than half of our oceans are now industrially fished using practices that remove unsustainably large numbers of fish at rates faster than they can reproduce. Poorly managed fisheries harm other animals and habitat in the process as well. Climate change has made ocean water more acidic, affecting phytoplankton—which supplies over 50% of the oxygen we breathe—and coral reefs, the most diverse marine habitats, which may not make it to the end of this century. 

Seize the Day

We still have time to change the course we are on. We can solve the accelerating biodiversity crisis by joining together to safeguard nature. Scientists are signaling that protecting 30% of all lands and waters by 2030 is one critical step needed to save nature and stabilize the climate. Currently, roughly 15% of the world’s land and 7% of the ocean is protected in some way.

More than 100 conservation groups, including Defenders of Wildlife, have united under the 30×30 goal, and the U.N. Convention on Biological Diversity included 30×30 in its draft 10-year strategy, which is expected to be finalized and approved by 196 world parties next year. “The cost to protect 30% of our planet is not inconsequential,” says Jamison Ervin of the U.N. Development Programme, but the “cost of inaction is unthinkable.”

A recent Defenders report found that most U.S. areas protected for biodiversity are federally managed, which means that federal agencies must step up to play an important role in achieving 30x30 in the U.S. “But we also found that 80% of biodiversity hotspots fall outside these federal lands, so we must invest in protecting vulnerable habitats and species on private lands,” says Defenders’ lead author Lindsay Rosa.

To this end, Defenders is calling for decision-makers to develop a national strategy that directs federal agencies to advance the 30x30 goal and ensure that agencies prioritize addressing and managing for climate change, pollution and invasive species.

“We also need to preserve, expand and increase funding for imperiled species protection under the Endangered Species Act, our nation’s flagship law for protecting species from extinction,” says Bob Dreher, Defenders’ senior vice president for conservation programs. “Years of underfunding have unfortunately rendered it less effective than Congress originally intended, but science shows that species can recover if we invest in their conservation. This should also include expanding our National Wildlife Refuge System—the nation’s premier federal lands system for protecting wildlife and habitat as anchors of biodiversity—to ensure that our wildlife have dedicated places of protection.”

Turning the tide on biodiversity loss will be no easy feat. But neither was going to the moon, banning DDT, wiping out polio and building a global satellite communication system. What we need is the political will and an engaged public—which is where Defenders’ advocacy, legal and policy work is laser-focused.

By preserving biodiversity, we let natural evolutionary processes continue, and that’s a long-term benefit that transcends human lifetimes. So, step outside and look around to see why it matters, not only for us, but for future generations. Celebrate that all forms of life above, below and all around make it possible for us to thrive. Our future depends on our coexistence with and respect for nature, and our connection to and dependence on nature demand we step up and lead. The planet deserves nothing less.

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Living Lightly

Now that you’ve read about all the amazing things biodiversity does for us, here are some things you can do.

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With engaging stories and spectacular photography, Defenders of Wildlife's magazine provides readers with a behind-the-scenes look at what biologists and conservationists are doing to protect imperiled wild animals and plants.

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