A Beginner’s Guide to Biodiversity: Everything You Need to Know
- Rachel Bailleau
- Sep 1
- 7 min read
Updated: Sep 27
Walk into a forest at dusk, pause by a wildflower meadow in spring, or watch birds dive for fish on the ocean. It’s in moments like this that we stop to marvel at biodiversity: the sheer variety of life, from the tiniest microbes to the tallest trees, all living and interacting together.
Biodiversity is the hum of bees, the flicker of tadpoles, the chatter of insects. From the birds in the sky to the hidden network of roots beneath your feet, biodiversity is life in all its forms, woven into one living tapestry. Each strand strengthens the others. So, as one species recovers, many others benefit. And when one species weakens, the whole web feels the strain.
Most people agree that protecting wild animals and plants is important. But we sometimes forget that thriving biodiversity is the foundation of our climate, our food, our health, and even our happiness. The more varied and vibrant life on Earth is, the more stable and resilient our world becomes.
This guide to biodiversity will help you understand why it matters, what’s at stake, and most importantly, what we can do together to protect biodiversity.
Guide to Biodiversity: Contents
What is Biodiversity?
Why Biodiversity Matters for Climate Stability
Biodiversity and Human Wellbeing
Building Resilience: How Biodiversity Helps Us Adapt
Indigenous Stewardship: Lessons from the Land
The Current State of Biodiversity
Success Stories: Nature’s Comeback
What You Can Do
Looking Forward
What is Biodiversity?
Biodiversity is the astonishing variety of life on Earth, at every scale: from genes within species, to the species themselves, to entire ecosystems. It’s what makes nature rich, resilient, and full of surprises.
This diversity exists in three key layers:
Genetic diversity is the variation within species that helps them adapt and survive. For example, some crops can resist drought while others cannot. Preserving many different varieties of food crops ensures we can grow them successfully in different climates and conditions, both now and in the future.
Species diversity is the richness of different plants, animals, fungi, and microorganisms. The more kinds of life there are, the more balanced an ecosystem becomes. Take beavers: their dams create ponds where insects and fish thrive, which then feed birds and other animals. The dams also reduce flooding and help purify water. When one species thrives, many others benefit.
Ecosystem diversity is the range of habitats, from rainforests to wetlands to grasslands. Each habitat supports unique communities of life with their own strengths. Forests, for instance, are powerful at purifying air and storing carbon, which helps slow climate change. Grasslands, on the other hand, can recover quickly after natural disasters such as fire, providing food for pollinators and grazing animals while forests take time to regrow.
Scientists have identified approximately 1.5 million species, but there may be tens of millions more that remain undiscovered. We’re only beginning to grasp the full scale of life’s variety.
And biodiversity isn’t just beautiful, it’s practical. It supports us in countless everyday ways:
A diverse gut microbiome helps us stay healthier and less prone to illness.
Protecting biodiversity in nature lowers the spread of infectious diseases.
Farms with more biodiversity are often more resilient and grow more food.
Healthy soil, mangroves, kelp forests, and many other habitats help protect us from flooding.
Many life-saving drugs come directly from wild plants, fungi, and microbes.
Biodiversity is life’s safety net, and when it thrives, so do we.
Nature’s Climate Solutions
Biodiversity and climate are inseparable. We can think of them as two sides to the same coin, or as life-long partners in keeping Earth’s systems in balance.
Forests lock away vast amounts of carbon. The Amazon rainforest alone stores an estimated 150–200 billion tons. That’s more than ten times the annual global emissions produced by people.
Peatlands, or bogs, may not look impressive, but they are extraordinary carbon vaults. In fact, peatlands store more carbon per hectare than forests, because carbon gets trapped and preserved in the wet soil for thousands of years.
Our oceans are just as vital. Marine ecosystems absorb about 25% of human CO₂ emissions. A single hectare of seagrass can capture and store carbon up to 35 times faster than a tropical rainforest.
Natural habitats actively remove carbon from the air through photosynthesis. In this process, plants absorb carbon dioxide, break it down, and store the carbon in their leaves, trunks, roots, and surrounding soil. The benefits go far beyond carbon storage. Forests create rainfall that cools the planet, seagrass beds protect coastlines from storms, and shade from trees lowers temperatures in heatwaves. These living systems stabilise the climate in ways no technology can fully replace.
The Feedback Loop:
When biodiversity declines, ecosystems lose stability and their ability to regulate climate weakens. That creates a dangerous feedback loop: biodiversity loss accelerates climate change, which in turn threatens biodiversity.
Biodiversity and Human Wellbeing
Don’t you just love win-win solutions? By protecting biodiversity, we can stabilise our climate, all while improving our health and food security.
Physical Health and Medicine:
Nature’s Pharmacy: Over 40% of modern medicines come from natural sources, such as aspirin from willow bark, antibiotics from soil fungi, and cancer treatments from marine organisms. Every lost species may mean a lost cure.
Genetic Diversity in Food: There are more than 6,000 edible plant species, yet humans rely on just a few dozen for most of our calories. Rice, wheat, maize, and potatoes dominate our diets. By eating a wider range of foods, we improve our health and preserve more food sources for the future.
Clean Air and Water: Forests filter pollutants from the air, wetlands purify water, and healthy soil can even break down contaminants.
Mental Health and Wellbeing:
Being in biodiverse environments isn’t just nice to look out. It reduces stress, anxiety, and depression, while boosting creativity and clear thinking. In Japan, doctors even prescribe shinrin-yoku, or forest bathing, because time spent among trees strengthens the immune system and lowers stress hormones.
Urban green spaces have benefits too: birdsong, flowers, or even wild plants sprouting through the pavement can lift mood and remind us that life endures. Studies show that trees not only cool cities and clean the air but can even reduce crime rates. Find out more about how getting outside can ease climate anxiety.
Economic Security:
Biodiversity supports livelihoods and the economy:
Fisheries and Oceans: About 820 million people worldwide rely on healthy oceans for food and income. If marine ecosystems collapse, communities lose their main source of protein and income.
Nature’s Return on Investment: Every dollar spent on conserving ecosystems can return multiple dollars in benefits. These benefits come through clean water, pollination of crops, flood protection, and tourism/recreation. Restoring wetlands, for example, can return $4–$10 for every $1 invested.
Did you know? Climate solutions are not too expensive! All the solutions to the climate crisis already exist, and Project Drawdown has costed them out. It would cost more to do nothing than to implement the solutions. Find out more in this guide to Climate Change.
Life will go on (with or without us)
You don’t need to worry about the end of the world.
Life has survived five major mass extinctions over the past 450 million years, events that wiped out up to 90% of species at a time. Yet, after each catastrophe, life rebounded, often in even more diverse forms. Today, ecosystems can still recover and flourish, even in altered landscapes.
In the long run, the Earth will endure, with or without humans. But the more we act to protect our climate and biodiversity, the less suffering there will be for people, domesticated animals, and wildlife in the short and medium term. Our efforts are about keeping the planet a place where humans and nature can thrive together. If we fail, the Earth will continue. But it may do so without us.
The Current State of Biodiversity
We are in the midst of what scientists call the Sixth Mass Extinction, but there is still hope.
Species are disappearing 1,000–10,000 times faster than natural background rates.
Humans have altered 75% of land and 40% of marine environments.
Yet awareness, technology, funding, and global policies are creating new momentum. We understand our impact, we understand the solutions, and now it’s about putting them into action.
Did you know? Though indigenous peoples have diverse cultures and languages, many share a common approach: managing land to support biodiversity. Research shows that areas under indigenous stewardship often have more species and healthier ecosystems than even some modern protected reserves. Protecting their land rights isn’t just about human rights; it’s crucial for the health of our planet.
Success Stories: Nature’s Comeback
When given space and protection, nature recovers fast.
Bald Eagles: From near extinction in the 1960s there are 70,000 breeding pairs today.
Mountain Gorillas: Once under 300 individuals, they are now thriving at over 1,000.
European Bison: Have gone from just 50 in captivity to 6,000 roaming free again.
Costa Rica: From 80% deforestation to over 50% forest cover restored.
The Thames River: Declared biologically dead in the 1950s. It’s now home to over 125 fish species, seals, and porpoises.
What You Can Do
Every action matters, especially multiplied across millions of people. We’ll look more deeply at ideas to help biodiversity in another article, but here are a few ideas to get started:
In Your Space: Plant native species in your garden, go pesticide-free, and support pollinators and wildlife with a water point in your garden.
Consumer Choices: Choose sustainable seafood by using resources like the Good Fish Guide, and looking out for certification like RSPO for products with palm oil. Support small-scale local farmers whenever possible.
Community Action: Volunteer with local conservation charities or a community garden.
Financial Support: Donate to causes you believe in, invest responsibly, and divest from fossil fuels.
Looking Forward: Connectivity and a Vision of Hope
Protecting and restoring habitats is crucial, but habitats alone aren’t enough. Wildlife needs safe corridors to move, forage, and find mates across large areas. Connectivity maintains the genetic health and resilience of populations, enabling species to survive climate change and other pressures.
Wildlife overpasses and bridges built over highways are a great example of doing this right. In countries like the Netherlands, Canada, and Costa Rica, the government has invested in bridges across major roads for animals, from deer to turtles, to safely cross. This is so important for linking fragmented habitats and keeping ecosystems functional.
Looking ahead, success will depend on:
Expanding and effectively managing protected areas.
Restoring degraded ecosystems at scale.
Creating connectivity corridors to link habitats.
Integrating biodiversity into all decisions.
Respecting indigenous stewardship and supporting community-based conservation.
Imagine cities full of wildlife, oceans alive with fish, and farms that work in harmony with nature. This is achievable if we act boldly now. Every choice, every action, every voice matters. Biodiversity is not optional. It is vital to human wellbeing at every level, and we now have the knowledge to protect it. Together, we can ensure life thrives, for people, for nature, and for future generations.
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