Why you should care about biodiversity

The variety of species in any given area — large or small — is what helps support life

|  Story by Meghan McMahon |


What is biodiversity and why does it matter?

As the saying goes, variety is the spice of life. In nature, variety comes in the form of biodiversity, that is the living things present in an area big or small.

Put simply, biodiversity is the collective variety of all living things — plants and animals, of course, but also fungi and bacteria and other microscopic organisms, according to the National Park Service.

Biodiversity is relative to an area. The biodiversity of Earth is vast and sweeping, with scientists estimating there are more than 8.7 million species of living things on the planet, according to National Geographic. Of these, less than 15 percent — about 1.2 million species — have been identified and described. Meanwhile, the biodiversity of your backyard, or a nearby park, is much more limited, with just a small number of species present, because the area is so much smaller.

That doesn’t mean protecting the biodiversity of your yard is any less important than protecting the biodiversity of our planet, however. In any given area — be it a continent or a country or a city block — all living things work collectively to maintain life and support the balance necessary for a healthy ecosystem, according to the World Wildlife Fund. The very variety of species in any given area — large or small — is what helps support life.

Biodiversity is important for reasons both obvious and less apparent. Quite obviously, biodiversity is key for healthy ecosystems, which we rely on for fresh water and clean oxygen and our food supply. It’s also a critical part of the solution to climate change and supports the world economy, according to Conservation International. In fact, more than 40% of the world economy and more than 80% of the needs of the world’s poor are derived from Earth’s biological resources.

Even the essence of who we are is linked to the biodiversity of the planet. Many of our most beloved species are the emblems and symbols of our states and nations, and religions from around the world include nature as a key component. If you’re a proud University of Wisconsin Badgers fan or fan of many of Chicago’s professional sports teams, those species that represent them have become part of your identity. A world without them would not be the same.

Biodiversity hotspots

A blue-spotted salamander on a moss-covered log.

A salamander's presence in an area is an indicator the habitat is clean. That's because amphibians breathe through their skin and are very sensitive to toxins and other contaminants. (Photo via Shutterstock)

Some areas are naturally more diverse than others, meaning more species occur there naturally than in many other places on Earth. These areas are called hotspots, and they are important both because of the sheer diversity of species and because the habitats in these areas are at risk of destruction, according to National Geographic. Hotspots make up less 3 percent of Earth’s land surface, but are home to more than 35 percent of our planet’s vertebrates and more than 44 percent of all plants.

Two criteria must be met for an area to be declared a biodiversity hotspot: It must have 30% or less of its original vegetation, and it must be home to more than 1,500 plant species that are endemic, meaning they do not grow anywhere else on Earth. These criteria mean that a particular area is both threatened and also irreplaceable, according to Conservation International.

Today, Earth is home to 36 biological hotspots, including the Horn of Africa, the tropical Andes, Madagascar, New Zealand, the Mediterranean basin and the mountains of Southwest China. Biological hotspots in the United States include the California Floristic Province, which is along the Pacific Coast, and the North American coastal plain, which includes coastal areas from Massachusetts south to Florida and the Gulf of Mexico coast.

Threats to biodiversity

A plastic bottle in water.

About 18 billion tons of plastic waste flows into Earth's oceans each year.  (Photo by Chad Merda)

The diversity of species in your backyard and on our planet are both at risk because of many human-caused factors. The five biggest threats to biodiversity are habitat loss, climate change, overexploitation, invasive species and pollution, according to the Food and Agriculture Organization of the United Nations.

The most significant cause of loss of biodiversity is habitat loss, the FAO reports. Habitat loss occurs when natural habitats and ecosystems are modified or destroyed for human purposes. Common ways humans cause habitat loss are through converting land for agricultural uses, deforestation, draining wetlands for development and damming rivers. In addition to habitat loss, these activities can also cause habitat fragmentation, which is dividing a habitat into segments such as through the building of roads. This fragmentation affects species because it makes it more difficult for them to traverse their natural habitat.

Climate change affects biodiversity because it changes the climate patterns of the planet’s ecosystems, which native species are reliant on for their survival, according to the FAO. When temperature and precipitation patterns change over time, some species may move into new areas to meet their climatic needs, but others may struggle because they cannot move or find new habitats where they can thrive.

Overexploitation is removing species from their habitat faster than they replenish themselves, such as by overfishing or allowing too many of a particular species to be hunted. When overexploitation occurs without attempts to correct it, species can become extinct.

Invasive species threaten biodiversity because they compete for resources with native species, and they can also become predators of native species and introduce new pathogens to an ecosystem, according to the FAO. Because invasive species often have no predators, their populations can often grow unchecked, which further degrades the ecosystem.

One of the main pollution threats to biodiversity is pollution of nutrients like nitrogen and phosphorous, which often occurs when fertilizers are applied to agricultural crops, the FAO reports. These pollutants have negative impacts on both aquatic and land-based ecosystems.

The extinction crisis

An aerial view of deforestation.

More than 6 trillion trees once stood on Earth, but today our planet has just 3 trillion trees, and we are losing 10 billion more a year. (Photo via Shutterstock)

Extinction is a natural process. In fact, as many as 99% of all species that have ever lived on Earth are extinct, according to National Geographic. Extinction occurs as species evolve over time in the changing world. Some species do not evolve as Earth changes and become extinct.

Although extinction is a normal part of life on Earth, it does not always occur at a constant or steady rate, National Geographic reports. The natural extinction rate, or background extinction rate, is the number of species that would become extinct if humans did not exist. The rate is estimated to be one extinction per 1 million species per year, according to the Center for Biological Diversity.

Today, we are experiencing extinctions at a vastly higher rate than the background rate — as many as 1,000 to 10,000 times higher, according to the World Wildlife Fund

When more than 75% of species are lost during a specific time period, it is called a mass extinction. Earth has experienced five mass extinctions in its history. The first, the Late Devonian Extinction, occurred about 370 million years ago, according to the American Museum of Natural History. The most recent mass extinction event, the Cretaceous-Paleogene Extinction, was about 66 million years ago.

The Cretaceous-Paleogene Extinction is known to most as the time when dinosaurs became extinct. However, we lost much more than dinosaurs from Earth. Scientists believe more than 75% of all species living on Earth at the time were lost during the extinction, which was caused by a large meteor that hit the planet, the natural history museum reports.

Today, we are experiencing a biodiversity crisis that may become Earth’s sixth mass extinction, according to the American Museum of Natural History. Unlike other mass extinctions, this current extinction event is not caused by a dramatic, life-altering event like a meteor or large-scale volcanic eruptions. Instead, it is being caused by one specific species — humans.

Our livelihood is a threat to the survival of millions of other living things. Habitat loss and habitat degradation caused by humans pose major risks to many species, as do human activities like overfishing, hunting and deforestation. In addition, we contribute to climate change, pollution, the spread of diseases from trade and the spread of invasive species, which further threaten many species, according to the National Wildlife Federation.

Many of the species that we are losing are species that have not yet been identified, the natural history museum reports. That is, we are losing species to extinction before we ever even knew they existed.

What we could lose

Hine's emerald dragonfly.

Only 300 or so of the federally endangered Hine's emerald dragonflies are known to exist in Illinois. (Photo courtesy of Paul Dacko)

Our current biodiversity crisis may seem abstract, but alarming numbers of species could be lost. Almost one-third of all living things globally are threatened with extinction, and this includes 41 percent of all amphibians, 26 percent of all mammals and 14 percent of all birds, according to the International Union for Conservation of Nature, which maintains the global Red List of Threatened Species.

The world’s critically endangered species include some that are very recognizable even if they live far from northern Illinois and even the United States. Eastern lowland gorillas, orangutans and black rhinos are all critically endangered, according to the Red List of Threatened Species. Closer to home, the rusty patched bumble bee, a bee native to Illinois and other parts of the Midwest and eastern United States, is critically endangered.

Species that are critically endangered are most at risk of extinction, but the Red List includes less at-risk categories as well. Species can also be endangered, vulnerable or near threatened. The U.S. Fish and Wildlife Service works with federal, state, local and tribal agencies as well as non-government organizations and private citizens to implement the Endangered Species Act of 1973, which governs how species are listed as threatened or endangered and what regulations are necessary to protect species from further population declines. In Illinois, the Endangered Species Protection Board is tasked with protecting plant and animal species native to the state that are in danger of being lost from the wild.

How you can help

Close-up of common milkweed.

Using native plants in home landscapes is a growing trend, and one that benefits the ecosystem around us. (Photo by Anthony Schalk)

Saving endangered and threatened species from extinction seems like a daunting task, and it requires effort at multiple levels to be successful. But it has been done before, and it can be done again.

Take the bald eagle. Our national emblem was once on the brink of extinction, but its population has since recovered to the extent that it is no longer listed as a threatened or endangered species. Why? Because once the cause of their sharp population decline was discovered — a pesticide called DDT was poisoning them when they consumed contaminated fish — laws were enacted to restrict the pesticide’s use and also protect remaining bald eagles across the United States.

In 1963, only 417 known nesting pairs of bald eagles were living in the contiguous United States, according to the U.S. Department of the Interior. DDT was banned in 1972, and the Endangered Species Act was enacted in 1973. These steps allowed the population of bald eagles and other affected birds, like peregrine falcons, to stabilize and then begin to rise.

In 2007, the bald eagle was removed from the country’s threatened and endangered species list, and the eagle population has continued to grow. It is estimated to have quadrupled since just 2009, with an estimated 316,700 individual bald eagles and more than 71,400 nesting pairs living across the contiguous U.S., the Department of the Interior reports.

Saving bald eagles from extinction required a large-scale effort, including passage of federal laws, but the general public played a role too. Everyone can play a role in saving threatened and endangered species from extinction, and it can start with something simple as learning about plants and animals at risk where you live, according to the Endangered Species Coalition.

Knowing what species are at risk in your area helps cultivate an understanding of how interesting and important they are and grows an awareness of how all species are connected and necessary for ecosystems to be healthy. Want to see what’s at risk in your neck of the woods? The Illinois Natural Heritage Database maintains a list of threatened and endangered species in Illinois that is broken down by county.

Dozens of threatened and endangered species live in Will County, including such varied species as grass pink orchids and Mead’s milkweed to Blanding’s turtles and Hine’s emerald dragonflies.


Once you learn about local endangered species, spend some time visiting open spaces — anything from a national park or wildlife refuge to a local city park or forest preserve — to see how different lands and habitats support different species.

There’s plenty of other steps you can take to help endangered species as well. Check out these suggestions from the Endangered Species Coalition:

  • Maintain bird feeders and bird baths.
  • Add native plants to your yard to offer food and shelter for wildlife.
  • Reduce or eliminate your use of pesticides and herbicides.
  • Recycle whenever possible and buy sustainable products.
  • Do not purchase products made from threatened and endangered species to avoid supporting the illegal wildlife trade.

(Lead image by Chad Merda) 

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