A rainforest filled with thousands of species is biodiversity. So is a prairie buzzing with insects, a coral reef crowded with fish, a teaspoon of living soil, and an old orchard containing varieties of apples that have nearly disappeared from commercial farms.
Biodiversity is the extraordinary variety of life on Earth—and the relationships that connect all of it.
Every May 22, the International Day for Biological Diversity draws attention to that living variety and why protecting it matters. The United Nations observance was established to increase understanding and awareness of biodiversity issues and commemorates the adoption of the text of the Convention on Biological Diversity on May 22, 1992.
But biodiversity isn’t only an environmental issue involving rare animals in distant forests. It helps support the food we eat, the water we drink, healthy soils, medicines, fisheries, forests, agriculture, and ecosystems that can better withstand environmental change.
Understanding biodiversity begins with realizing that protecting nature isn’t simply about saving individual species. It’s about protecting the complicated living systems of which those species—and we—are part.
🌎 What Is Biodiversity?
Biodiversity means biological diversity, but it encompasses more than the number of species living on Earth.
Scientists generally consider biodiversity at three interconnected levels.
There is genetic diversity within species. Different populations and individuals carry different genetic traits, some of which may help a species withstand disease, drought, changing temperatures, or other pressures.
There is species diversity, meaning the variety of plants, animals, fungi, microorganisms, and other organisms within an area.
And there is ecosystem diversity: forests, wetlands, grasslands, coral reefs, rivers, deserts, mangroves, tundra, and the countless other environments created by interactions between organisms and their physical surroundings.
All three levels matter.
A field containing a single crop variety may contain plants, but it doesn’t possess the same genetic diversity as a farming system containing numerous locally adapted varieties. A forest containing hundreds of interacting species is different from a plantation composed primarily of one tree species.
Biodiversity is therefore not simply a count of how many living things we can name. It also describes variation and relationships throughout the living world.
📅 What Is the International Day for Biological Diversity?
The International Day for Biological Diversity is observed annually on May 22.
The United Nations originally designated December 29 as the International Day for Biological Diversity because that was the date the Convention on Biological Diversity entered into force. In 2000, the observance was moved to May 22 to commemorate the adoption of the Convention’s text in 1992.
The purpose is to increase understanding and awareness of biodiversity issues while encouraging support for conservation and the sustainable use of biological resources.
That may sound like a subject primarily for scientists and governments, but biodiversity touches almost every part of daily life.
The strawberries at a farmers market, bees visiting garden flowers, fungi breaking down fallen leaves, microbes living in healthy soil, fish supporting coastal communities, forests filtering water, and plant compounds used to develop medicines are all parts of the biodiversity story.
🍎 Biodiversity Helps Put Food on Our Tables
One of the easiest ways to understand biodiversity is to look at dinner.
Agriculture depends on much more than the crop or animal being raised. Healthy soils contain enormous communities of organisms. Predatory insects can help control crop pests. Birds and bats can influence insect populations. Wild relatives of cultivated plants contain genetic traits that may prove useful when breeders need crops capable of tolerating disease, drought, heat, or other changing conditions.
Then there are pollinators.
According to the Food and Agriculture Organization of the United Nations, roughly three-quarters of the world’s leading food crops depend at least partly on animal pollination. Those crops include many fruits, vegetables, nuts, and seeds that contribute heavily to diverse and nutritious diets.
Genetic diversity matters as well.
Thousands of varieties of crops and breeds of domesticated animals have developed around the world, often adapted to particular climates and landscapes. When that diversity disappears, agriculture can lose options that may become increasingly valuable as growing conditions change.
Protecting biodiversity therefore isn’t separate from protecting food security. The two are deeply connected.
🐝 A Garden Is a Tiny Ecosystem
You don’t need to travel to a tropical rainforest to see biodiversity in action.
Look closely at an ordinary garden.
Flowers may attract native bees, butterflies, moths, beetles, and hoverflies. Caterpillars become food for birds. Spiders hunt among foliage. Lady beetles and lacewings prey on other insects. Earthworms and microorganisms help break down organic material in the soil.
Even plants that aren’t deliberately cultivated can become part of this network.
A more diverse garden doesn’t automatically become perfectly balanced or pest-free, but planting a variety of flowers, herbs, shrubs, and other plants can provide more opportunities for wildlife than a landscape containing very little plant diversity.
That’s one reason modern approaches to companion planting with tomatoes focus increasingly on creating diverse habitat for beneficial insects rather than expecting individual plants to magically repel every pest.
A backyard may be tiny compared with a national park, but it is still part of a larger landscape.
🌳 Biodiversity Helps Ecosystems Function
An ecosystem isn’t simply a collection of species sharing the same address.
Organisms interact constantly.
Plants capture energy from sunlight. Pollinators move pollen. Fungi and microorganisms break down dead material. Predators influence prey populations. Herbivores shape vegetation. Seeds are dispersed by wind, water, mammals, and birds. Soil organisms recycle nutrients that eventually become available to plants again.
Remove one species and an ecosystem may adjust relatively easily. Remove enough species—or lose organisms performing particularly important ecological functions—and those relationships can begin to change dramatically.
Scientists sometimes describe biodiversity as contributing to ecosystem resilience. A diverse system may have more ways to respond when conditions shift because different organisms perform overlapping or complementary roles.
That doesn’t mean every ecosystem with more species will automatically survive every disturbance. Ecological relationships are far more complicated than that.
It does mean that protecting functioning communities of organisms is generally much more meaningful than treating species as isolated entries on a checklist.
💧 Healthy Ecosystems Support Clean Water
Water and biodiversity are closely connected.
Forests, wetlands, grasslands, soils, rivers, and other ecosystems influence how water moves through landscapes.
Vegetation can slow runoff. Roots help stabilize soil. Wetlands can trap sediments and absorb some pollutants. Healthy watersheds influence both water quality and availability.
When ecosystems are degraded, those functions can be weakened.
That is one reason conservation isn’t simply about keeping landscapes beautiful. Protecting forests, wetlands, and watersheds can provide practical benefits for communities downstream.
The World Health Organization emphasizes that human health depends on functioning natural systems that provide fresh water, food, healthy soils, clean air, and other essential resources.
We depend on nature even when the connection isn’t immediately visible from the kitchen faucet.
💊 Nature Has Contributed to Medicine
The natural world has also played an important role in medicine.
Plants, fungi, microorganisms, and other organisms produce an extraordinary range of chemical compounds. Some have directly become medicines, while others have provided models or inspiration for pharmaceutical development.
That doesn’t mean every wild plant is a medicine or that “natural” automatically means safe. Many naturally occurring substances are ineffective, irritating, or poisonous.
The important point is that biological diversity represents an enormous library of chemistry created through evolution.
When a species disappears before it has been studied, we don’t necessarily know what biological information disappears with it.
Protecting biodiversity therefore preserves possibilities as well as known benefits.
🌊 The Ocean Depends on Biodiversity Too
Biodiversity doesn’t stop at the shoreline.
Coral reefs, mangrove forests, seagrass meadows, kelp forests, estuaries, the open ocean, and deep-sea environments contain complex communities of organisms.
These ecosystems support fisheries, help cycle nutrients, provide nursery habitat for marine species, protect coastlines, store carbon, and sustain food and livelihoods for communities around the world.
Coral reefs are particularly striking examples. Although they occupy a relatively small portion of the ocean, they provide habitat for an extraordinary variety of marine life.
Their vulnerability also demonstrates how multiple environmental pressures can interact. Rising ocean temperatures, acidification, pollution, destructive fishing practices, and coastal development can all affect marine ecosystems.
If you’d like to meet a few of the remarkable animals that depend on healthy oceans, explore our 8 Fascinating Ocean Creatures for World Oceans Day.
🦜 Losing One Species Can Mean Losing Much More
It is tempting to measure biodiversity loss only in extinctions.
But a species doesn’t have to disappear completely for its ecological importance to diminish.
A bird may technically survive while becoming so scarce that it no longer disperses seeds across the landscape as it once did. A pollinator population can decline while the species itself remains far from extinction. Fish populations can shrink enough to change food webs long before the last individual disappears.
Conservationists therefore monitor abundance, distribution, habitat quality, and population trends in addition to extinction.
The IUCN Red List currently includes assessments of more than 175,000 species, with tens of thousands classified as threatened with extinction.
Parrots illustrate the problem particularly well. Habitat destruction and wildlife trade have placed pressure on numerous species, even though parrots as a group remain wonderfully diverse. Our guide to 15 fascinating parrot facts for World Parrot Day explores both their remarkable adaptations and the conservation challenges many species face.
⚠️ Why Is Biodiversity Declining?
Biodiversity has always changed over Earth’s history. Species evolve, populations shift, environments change, and extinction is a natural part of evolution.
What concerns scientists today is the speed and scale of human-driven change.
The major direct pressures identified by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services include changes in land and sea use, direct exploitation of organisms, climate change, pollution, and invasive alien species.
Habitat change is particularly important.
Forests may be cleared, wetlands drained, grasslands converted, rivers altered, and coastlines developed. Sometimes habitat remains but becomes divided into small isolated fragments that populations struggle to move between.
Overharvesting and wildlife exploitation can reduce populations faster than they reproduce. Pollution alters terrestrial, freshwater, and marine environments. Invasive species can transform ecosystems far from their original ranges.
Climate change increasingly interacts with these existing pressures by altering temperatures, rainfall, fire patterns, ocean conditions, seasonal timing, and the geographic ranges suitable for many species.
Biodiversity loss rarely has one simple cause.
🌡️ Biodiversity and Climate Change Are Connected—but Not the Same
Climate change and biodiversity loss are closely linked environmental challenges, but they aren’t interchangeable.
Climate change can damage biodiversity. Rising temperatures, changing rainfall, extreme events, warming oceans, sea-level rise, and shifting seasonal patterns can alter habitats and place additional pressure on species.
At the same time, functioning ecosystems can help store carbon and buffer some effects of climate change.
Forests, peatlands, seagrass meadows, mangroves, and healthy soils all interact with the carbon cycle.
But protecting biodiversity cannot be reduced entirely to storing carbon.
A plantation consisting of one rapidly growing tree species might store carbon while supporting far less native biodiversity than the complex natural forest it replaced.
Effective environmental protection needs to consider both climate and biodiversity rather than assuming that solving one automatically solves the other.
🐘 Protecting Habitat Protects More Than One Species
Charismatic animals frequently become symbols of conservation.
Elephants, lions, sea turtles, parrots, whales, and other familiar species can inspire people to care about wildlife. But protecting the habitat needed by one wide-ranging animal can benefit thousands of less famous organisms living alongside it.
Conserving an elephant landscape, for example, also means conserving plants, insects, birds, reptiles, fungi, microorganisms, and other mammals sharing that ecosystem.
The same principle applies closer to home.
A wetland protected for migrating birds may also support fish, amphibians, aquatic plants, insects, and countless microscopic organisms.
That broader perspective is useful when reading about individual conservation stories, including the challenges facing animals discussed in our World Elephant Day guide.
Every species exists within a community.
🌾 Genetic Diversity Is Easy to Overlook
A world containing wheat, corn, tomatoes, apples, cattle, and chickens might sound biologically diverse.
But diversity also exists within those species.
Consider tomatoes. Thousands of varieties differ in flavor, color, shape, disease resistance, growth habit, climate tolerance, and other characteristics.
That genetic variation represents options.
A variety that is commercially unimportant today might contain traits useful for breeding tomorrow’s crops. Traditional livestock breeds may possess adaptations to local climates or diseases. Wild relatives of cultivated plants may contain useful genetic material absent from modern varieties.
Once unique genetic diversity disappears, recreating it isn’t simple.
Seed banks, botanical gardens, agricultural collections, traditional farming systems, and conservation of wild relatives all help preserve this less visible level of biodiversity.
🌺 Native Plants Can Support Local Biodiversity
For home gardeners, one of the most practical ways to think about biodiversity is through habitat.
Native plants have evolved alongside other organisms within a region. Many provide food or shelter to native insects, birds, and other wildlife.
That doesn’t mean every garden must contain exclusively native species, nor does planting one native flower instantly restore an ecosystem.
The bigger idea is to make landscapes more biologically useful.
A yard containing flowers across multiple seasons, shrubs, trees, places to shelter, and fewer unnecessary pesticides can offer far more habitat than one dominated by pavement or a single closely mown plant species.
Even balconies and small urban gardens can provide nectar, pollen, or resting places for insects and birds.
Gardens aren’t substitutes for conserving large natural ecosystems, but they can still contribute to a more connected landscape.
🌍 Conservation Really Can Make a Difference
The scale of biodiversity loss can make conservation seem hopeless, but species recovery programs show that decline isn’t always inevitable.
Protected areas, habitat restoration, invasive-species control, wildlife-trade regulations, captive breeding, sustainable resource management, and community-led conservation have all helped prevent extinctions and restore populations.
IUCN reports that extinction risk trends would have been substantially worse without conservation action.
The important lesson isn’t that everything is fine.
It is that action matters.
Conservation works best when the underlying causes of decline are addressed rather than simply keeping the final few individuals of a species alive.
Saving wildlife often means protecting habitat, reducing unsustainable exploitation, improving environmental management, involving local communities, and committing to the work for decades rather than months.
🏡 What Can Individuals Do for Biodiversity?
Biodiversity loss is driven by large systems involving land use, agriculture, fisheries, industry, transportation, consumption, climate, and public policy. Individual behavior alone cannot solve it.
But individuals aren’t irrelevant either.
What we plant, purchase, waste, eat, discard, and support collectively influences landscapes and resources.
At home, that can mean planting a greater variety of useful plants, reducing unnecessary pesticide use, keeping invasive plants from escaping cultivation, preventing litter, reducing food waste, keeping cats from hunting wildlife outdoors, and making windows safer for birds.
It can also mean supporting parks, conservation organizations, responsible producers, habitat-restoration projects, and policies based on sound conservation science.
Our World Environment Day guide to simple sustainable practices includes additional everyday ideas that complement biodiversity conservation.
No single action will protect the living world.
Many actions, at many scales, can.
🔬 We Still Have an Extraordinary Amount to Learn
Perhaps one of the most remarkable facts about biodiversity is how incomplete our knowledge remains.
Scientists continue discovering new species, documenting previously unknown relationships, revising evolutionary trees, and learning how organisms interact within ecosystems.
Even familiar environments contain mysteries.
Soils hold astonishing microbial communities. Deep oceans remain poorly explored. Insects and fungi are vastly more diverse than most people encounter in everyday life. Species already known to science may have behaviors or ecological roles that researchers are only beginning to understand.
That uncertainty makes biodiversity conservation even more important.
We aren’t protecting only what we already understand.
We are protecting a living world that still contains discoveries waiting to be made.
🌿 Why Biodiversity Matters
The strongest argument for biodiversity isn’t that every species needs to prove its usefulness to humans.
Other forms of life have existed for millions of years independently of what benefits we eventually discover in them.
But if we look only at human well-being, the case remains overwhelming.
Biodiversity contributes to food production, clean water, healthy soils, fisheries, medicines, livelihoods, cultural traditions, climate regulation, recreation, and ecosystems capable of supporting life.
It also gives the world much of its wonder.
A planet with coral reefs, rainforests, orchids, elephants, beetles, whales, fungi, hummingbirds, prairie flowers, frogs, and parrots is profoundly richer than one in which only the species most useful to us remain.
International Day for Biological Diversity gives us one day each year to focus attention on that richness.
Protecting it is work for every day that follows.
🔗 Related Articles
- World Environment Day: 7 Simple Sustainable Practices for Everyday Life
- 8 Fascinating Ocean Creatures for World Oceans Day
- World Parrot Day: 15 Fascinating Facts About Parrots
- World Elephant Day: Fascinating Facts About Elephants & Why They Need Protection
- 7 Best Companion Plants for Tomatoes: What Actually Helps
📚 Sources & Further Reading
- Convention on Biological Diversity — International Day for Biological Diversity
- Convention on Biological Diversity — About Biodiversity
- IPBES — Global Assessment Report on Biodiversity and Ecosystem Services
- IUCN — Biodiversity
- IUCN — The IUCN Red List of Threatened Species
- Food and Agriculture Organization — Biodiversity
- Food and Agriculture Organization — Pollination Services for Sustainable Agriculture
- World Health Organization — Nature and Health
