If we lost just a few patches of land around the world, we’d risk wiping out nearly half of all plant and animal species.

That’s because over 50% of the world’s plant species and 42% of terrestrial animals live in regions that make up less than 2.5% of the Earth’s land surface.

These rare and threatened regions are known as biodiversity hotspots, but the term is often misunderstood. It’s not just a label for any lush forest or coral reef. It’s a specific scientific classification tied to both biological richness and environmental risk. Learning about them is also a powerful Earth Day activity, helping people of all ages understand why conservation efforts matter.

So, what is the definition of a biodiversity hotspot? How does a region earn that label? And why are these ecological hotspots considered some of the most important places to protect on the planet?

We’ll break down what qualifies a region as a bio hotspot, how many of them exist, and why they matter, not just for the species that live there, but for the health of our planet as a whole.

What is a Biodiversity Hotspot?

At its core, a biodiversity hotspot is a place that’s both exceptionally rich in life and at serious risk of losing it. But this label isn’t just about being lush or full of wildlife; it comes with clear scientific criteria.

To be recognized as a biodiversity hotspot, a region must meet two conditions:

It must have at least 1,500 species of vascular plants that exist nowhere else, meaning they’re endemic.
And it must have lost at least 70% of its original natural vegetation, usually due to human activities like agriculture, logging, or urban development.

So when we ask, what is the definition of a biodiversity hotspot, we’re not just talking about scenic landscapes. We’re referring to areas that are biologically unique and deeply threatened, making them top priorities for conservation.

This concept helps researchers and environmentalists focus attention on places where action can make the most significant difference. These ecological hotspots often support an incredible variety of plants, mammals, birds, and insects, all tightly interconnected, and many found nowhere else on Earth.

How Many Biodiversity Hotspots Are There in the World?

The total number of biodiversity hotspots in the world currently stands at 36, as officially recognized by global conservation organizations like Conservation International. These hotspots are spread across nearly every continent, except Antarctica, and represent areas where conservation efforts can have the most significant impact.

Together, these regions cover less than 2.5% of Earth’s land surface, yet they support more than half of all known plant species and a large portion of terrestrial animals. What makes them urgent priorities isn’t just their richness in life, but the extent to which these ecosystems have already been degraded. Habitat loss, agriculture, mining, urbanization, and climate change are putting many of these areas on the brink.

Here’s a closer look at some of the most well-known ecological hotspots across the globe:

Amazon Basin (South America)

Amazon Basin (South America)

The Amazon spans across nine countries and holds an astonishing share of global biodiversity. It contains over 16,000 species of trees, and one in every ten known species on Earth can be found here. But beyond its biological importance, the Amazon acts as a carbon sink, storing over 100 billion metric tons of carbon and influencing rainfall patterns across South and even North America. Large portions of the forest are being lost each year to cattle grazing, soybean farming, and illegal mining. The damage doesn’t just affect local species; it accelerates climate change and disrupts global weather systems.

Indo-Burma (Southeast Asia)

Indo-Burma (Southeast Asia)

Stretching across Southeast Asia, Indo-Burma is one of the most biologically rich yet least protected regions in the world. It is home to more than 13,500 plant species, and nearly half of them are found nowhere else. The region’s freshwater ecosystems support rare turtles, giant catfish, and birds like the critically endangered white-shouldered ibis. But dam construction, wetland loss, and intensive farming continue to fragment what’s left. One of the most iconic species here is the saola, sometimes called the “Asian unicorn”, a mammal so rare that it’s been seen only a handful of times by scientists since its discovery in the 1990s.

Sundaland (Indonesia and Malaysia)

Sundaland (Indonesia and Malaysia)

Sundaland includes the Indonesian and Malaysian islands of Borneo, Sumatra, and Java. These equatorial rainforests are some of the oldest on Earth, home to rare and remarkable species like orangutans, pygmy elephants, and the Sumatran rhinoceros. It’s also where you’ll find Rafflesia Arnoldii, the world’s largest flower, which blooms directly from the forest floor. Unfortunately, Sundaland is also ground zero for palm oil expansion. Millions of acres of forest have been cleared or burned in recent decades, making it one of the most rapidly disappearing hotspots on the planet.

Western Ghats and Sri Lanka (South Asia)

Western Ghats and Sri Lanka (South Asia)

This mountain range along India’s western coast, combined with the nearby island nation of Sri Lanka, is one of the oldest and most diverse ecosystems in South Asia. Nearly 80% of the amphibians here are endemic, meaning they exist nowhere else. Tiny frogs that emerge only during the monsoon, ancient ferns, and endangered primates like the lion-tailed macaque all live in this region. Beyond biodiversity, the Western Ghats are a vital watershed, supplying water to millions in peninsular India. Yet, hydropower projects, tea and coffee plantations, and urban expansion continue to chip away at its forest cover.

Madagascar and the Indian Ocean Islands

Madagascar and the Indian Ocean Islands

Madagascar is a world apart; nearly 90% of its species are endemic, a result of its long geographic isolation. From lemurs and tenrecs to bizarrely shaped baobab trees, the island is full of life that evolved nowhere else. It also holds an incredible diversity of medicinal plants. But severe poverty, charcoal dependency, and slash-and-burn agriculture have led to catastrophic deforestation. The spiny forest of southern Madagascar, for example, has been reduced to small fragments, many of which are still unprotected. Conservation here is urgent, not only because of what could be lost, but because what’s here exists nowhere else.

California Floristic Province (USA)

California Floristic Province (USA)

Often overshadowed by tropical forests, the California Floristic Province is the only biodiversity hotspot in the continental United States. It boasts more than 3,400 plant species, 60% of which are endemic, and is especially rich in wildflowers, chaparral shrubs, and oak woodlands. This region plays a crucial role in pollinator networks and is home to many native bee species that support agriculture beyond California’s borders. But urban sprawl, drought, and invasive grasses continue to erode its ecosystems. Despite the presence of protected areas, only about a quarter of its original natural vegetation remains intact.

Each of these biological hotspots illustrates the same pattern: rich in unique species, deeply tied to local communities and global systems, and rapidly shrinking. Collectively, they represent some of the most valuable and vulnerable ecosystems on the planet.

Why These Biodiversity Hotspots Matter

Why These Biodiversity Hotspots Matter

Biodiversity hotspots matter because they represent the most irreplaceable life on Earth, and the most fragile. When we lose them, we lose far more than species; we lose vital life-support systems. Here is how these biodiversity hotspots contribute to life on our planet:

Regulate Global Climate

Tropical forests in hotspots like the Amazon, Congo Basin, and Southeast Asia act as carbon sinks. They store vast amounts of carbon dioxide and help cool the planet. When these forests are cleared, not only is that carbon released back into the atmosphere, but we also lose one of our strongest natural defenses against global warming.

Safeguard Water Supply

Many biodiversity hotspots are located in mountainous or forested areas that feed rivers and groundwater systems. The Western Ghats, for instance, supply water to millions of people in southern India. In Mesoamerica and the Andes, cloud forests collect moisture and stabilize local water cycles. Without intact ecosystems, droughts become more extreme, floods more frequent, and water access more uncertain.

Supports Local Economies

From wild pollinators that sustain crops to fish populations that feed communities, hotspots directly support livelihoods. In Indo-Burma and Sundaland, millions depend on rivers and wetlands for freshwater fish. In California, native bee species help pollinate almonds, tomatoes, and other major crops. Biodiversity here isn’t just beautiful; it’s functional, and its collapse would have a real economic impact.

Support Modern Medicine

Nearly 25% of modern medicines come from rainforest plants, and an estimated 70% of those plants have properties that can help fight cancer. Many of these species grow in biodiversity hotspots, making their protection critical for future medical breakthroughs.

One standout example is Madagascar’s rosy periwinkle (Catharanthus roseus), which gave us vincristine. This chemotherapy drug has dramatically increased survival rates for childhood leukemia, from around 20% in the 1960s to over 80% today.

However, less than 5% of rainforest plant species have been scientifically screened for medical use, meaning countless potential cures remain undiscovered in disappearing forests.

Serve as Cultural Anchors

For Indigenous and local communities, these ecosystems are deeply tied to identity, tradition, and spiritual beliefs. Preserving biodiversity isn't just about biology; it’s about protecting worldviews, practices, and human dignity. Conservation efforts in hotspots often succeed when they’re community-led, because the people who live there understand the land’s value beyond metrics.

In short, when we invest in protecting these bio hotspots, we’re not just preserving rare species, we’re protecting the systems that keep our planet livable.

Common Threats Affecting These Fragile Ecosystems

Common Threats Affecting These Fragile Ecosystems

Biodiversity hotspots aren’t just biologically rich, they’re biologically endangered. And for many, the threats continue to grow, overlapping and compounding faster than restoration efforts can keep up. Here are a few common threats that affect these ecosystems:

Habitat Loss

This is the most pressing and visible threat. Forests are cleared to make way for cash crops, grazing land, mining, and logging, often without permits or environmental safeguards. In the Amazon, millions of hectares are lost each year to cattle ranching. In Southeast Asia, entire landscapes are leveled for palm oil plantations.

This kind of large-scale destruction doesn’t just affect trees; it wipes out everything that depends on them, from birds and insects to indigenous communities. As habitats shrink, species are forced into smaller areas, increasing competition, inbreeding, and vulnerability to disease.

Infrastructure and Development

Roads, highways, dams, and pipelines carve through once-intact ecosystems, fragmenting forests and isolating wildlife populations. When a road cuts through a forest, it’s not just a line on a map; it becomes a barrier to movement, breeding, and feeding.

In Indo-Burma, hydropower dams have disrupted fish migrations, altered flood cycles, and displaced local communities. In the Western Ghats, expanding townships and resorts are pushing deeper into forested areas. Even well-intentioned development can accelerate biodiversity loss if it's not planned with ecosystems in mind.

Climate Change

The effects of climate change are exceptionally hard-hitting in biodiversity hotspots because these regions often host species adapted to particular conditions. A shift of even 1–2°C in average temperature can wipe out high-altitude frogs, forest-dwelling orchids, or coral reef species that have nowhere else to go.

In the Andes and Himalayas, plants and animals are moving upslope to escape warming, but there’s only so much mountain left. Rising sea levels also threaten island hotspots like the Philippines and Madagascar, where entire habitats may vanish beneath the ocean.

Invasive Species

When non-native plants or animals are introduced, whether accidentally or intentionally, they often thrive at the expense of native species. Invasive plants may alter soil chemistry, outcompete native trees, or fuel more frequent fires. Invasive predators like feral cats, rats, or cane toads can decimate vulnerable native species, especially on islands. In biodiversity hotspots, where many species have evolved in isolation, even a single invasive species can collapse an entire food web.

Illegal Wildlife Trade

From slow lorises and pangolins to rare orchids and tropical fish, many species native to biodiversity hotspots are targeted for the global wildlife trade. Exotic pet markets, traditional medicine, fashion, and collectibles drive the demand.

Often, these animals are taken from the wild under brutal conditions, transported illegally, and sold at high prices. Beyond the immediate loss of individual animals or plants, this trade reduces population viability, disrupts ecological balance, and undermines local conservation efforts.

What makes these threats so dangerous is how they interact. A single region might face deforestation, drought, invasive species, and poaching, all at once. Hence, without rapid, coordinated, and well-supported intervention, some of the world’s most valuable and unique biodiversity could disappear within our lifetime.

How We Can Restore Bio Hotspots

While biodiversity hotspots are defined by what they’ve already lost, the story doesn’t have to end there. Across the globe, efforts are underway not just to protect what remains, but to rebuild what’s been damaged. Reforestation, habitat restoration, and locally led conservation projects are proving that nature can recover, if given the chance.

Reforestation as a Starting Point

In many hotspots, restoring native forests is the most powerful way to bring life back. Replanting native tree species helps stabilize soil, store carbon, support pollinators, and create corridors for wildlife to return. In the Atlantic Forest of Brazil, once reduced to fragments, restoration projects have successfully reconnected forest patches and brought back rare bird species. In Madagascar, community-led tree planting has helped slow erosion and revive degraded land that once supported lemurs and endemic plants.

But reforestation isn’t just about planting trees. It’s about restoring functioning ecosystems, bringing back native understory plants, reintroducing keystone species, and giving natural regeneration a chance to take over. When it is done thoughtfully, it becomes one of the most cost-effective tools for long-term conservation.

Protecting What’s Still Intact

Of course, it’s far more effective to protect forests than to rebuild them from scratch. That’s why expanding and enforcing protected areas remains critical. Across biodiversity hotspots, conservation groups and governments are working to halt deforestation, prevent illegal mining, and reduce encroachment through stronger environmental regulations. When legal protection is paired with local stewardship, the impact is even greater.

Empowering Local Communities

Restoration works best when it’s rooted in the communities that live closest to the land. Many Indigenous and rural communities in hotspot regions already manage their environments sustainably, but what they often lack is legal land ownership, funding, or support. Conservation initiatives that respect land rights and invest in local leadership tend to have the strongest and longest-lasting results.

What You Can Do

Support reforestation efforts through trusted organizations working in biodiversity hotspots. Choose sustainably sourced products, like FSC-certified wood, deforestation-free palm oil alternatives, and shade-grown coffee, to reduce pressure on forest ecosystems. If you travel, opt for eco-tourism that contributes to local conservation instead of exploiting wildlife. And wherever you are, raising awareness about the value of biodiversity helps keep this issue visible and urgent.

Revive Bio Hotspots with Every Tree You Plant

Bio hotspots are disappearing faster than they can recover, but reforestation can help turn the tide. At Plantd, we believe that real change starts with a single tree. Whether you're an individual looking to make a difference or a business aiming to support real environmental impact, you can play a part in restoring the planet’s most threatened ecosystems.

Our mission is simple: restore forests where biodiversity is under threat and help nature thrive again. Every tree you plant with Plantd supports trusted reforestation projects that regenerate habitats, strengthen communities, and protect species on the edge of extinction.

If you’re ready to move from awareness to action, join us in restoring biodiversity hotspots around the world.

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With verified planting partners, transparent impact tracking, and a focus on ecological restoration, Plantd makes it easy to take action that truly matters for biodiversity, for climate, and for future generations.

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