Biological diversity is the foundation of life on Earth, encompassing genes, species, ecosystems, and their essential functions.
Amongst the planet’s most biodiverse nations are extraordinary species of birds, amphibian species, reptile species and more vital for ecological balance. However, threats like deforestation, pollution, and climate change challenge these nations’ unique environments, demanding urgent global action.
Supported by initiatives from organisations like the United Nations, efforts to conserve biodiversity aim to protect irreplaceable species and habitats. This article highlights 20 of the world’s most megadiverse countries and their invaluable contributions to our planet’s future.
What Does Biodiversity in a Country Mean?
Biodiversity encompasses the vast variety of life forms on Earth, including genes, species, ecosystems, and the essential functions they support.
While there are an estimated 8.7 million species on Earth, experts suggest that 5 million of them remain undiscovered. It’s believed that around 85% of land species are unidentified, and 90% of marine life.
With a rate of discovery around 18,000 a year, it could take about 277 years to fully comprehend the wonders of Earth’s ecological biodiversity. However, that also means up to 1.5 million new species could be discovered within an average human’s lifetime.
From Madagascar or the Eastern Himalayas to the Mesoamerican Forests and Sundaland, this article will provide insights into the ecological contexts, unique habitats, and species diversity of each megabiodiverse country.
How Biodiversity is Measured
Biodiversity can be measured within 4 categories: genetic diversity, species diversity, ecosystem diversity, and functional diversity.
Genetic biodiversity refers to the variety of genes in a population or species, encompassing ranges of gene combinations, alleles, and sequences of DNA.
Species diversity encompasses the variety of entire species on Earth or within an ecosystem.
Ecosystem diversity covers the variety of ecosystems across the planet, in a set region, geographical context, or within a specific ecosystem.
Functional biodiversity refers to varieties of functions (such as decomposition), biological roles (such as pollinators), and processes (such as photosynthesis).
Brazil
Brazil is home to some of the richest and most varied ecosystems in the world, including the Atlantic Forest, Pantanal, Caatinga, marine ecosystems, the Cerrado, and even around 60% of the Amazon Rainforest.
For instance, the Cerrado is the most biodiverse savannah on the planet, also extending into Bolivia and Paraguay.
With over 12,000 plant species, 251 mammal species, 800 fish and 856 bird species, the savannah ecosystem is essential for biodiversity. Notably, it hosts the rare Spix’s macaw, the giant armadillo and the maned wolf.
Indonesia
Indonesia has over 17,000 islands, ranging from Simping Island, at around 2,000 square meters, to Borneo, at around 290,000 square miles.
The isolated islands have achieved unique evolutionary developments over time, illustrated by the Komodo dragon found only on a few Indonesian islands, which has evolved to become the largest living reptile due to the lack of natural predators.
Indonesia boasts the Coral Triangle, named by some as the most important part of the ocean; home to 76% of the world’s coral species plus with more reef fish than anywhere else. The marine region hosts a vast amount of marine life, and touches across parts of Southeast Asia.
Mexico
From Panama to central Mexico, Mesoamerica is a critical biodiversity hotspot, enveloping eight countries and various islands. A significant portion of southern Mexico lies within this hotspot, including tropical lowlands and montane cloud forests, which bridge species between North and South America.
This region also serves as a vital migratory corridor, supporting over 225 bird species. With 17,000 vascular plant species and over 3,000 of those endemic species, Mesoamerica is crucial for global biodiversity and includes vast carbon-rich territories vital for climate regulation. Additionally, it supports numerous indigenous communities, emphasizing its ecological and cultural importance.
Colombia
Colombia boasts a range of diverse ecosystems, including the Andes Mountains, Caribbean, Pacific coasts, Orinoco River Basin, and the Amazon Rainforest covering around 35% of Colombia’s land.
The country has over 50,000 plant species including over 4,000 orchid species, as well as over 1,900 bird species—the highest of any country. Some highly notable examples are the Choco toucan and the Cattleya trianae orchid (the country’s national flower).
The Colombian Chocó Rainforest is one of the wettest regions on Earth, with up to 14 metres of annual rainfall in some areas, supporting diverse species with lush, thriving ecosystems.
Peru
Around 60% of Peru is covered by the Amazon, including pink river dolphins, jaguars, and macaws, as one of the most biologically diverse parts of the Amazon basin. Moreover, the Andes Mountains have cloud forests, páramos (high-altitude ecosystems with the world’s richest high-mountain flora—such as Frailejones or peat mosses).
Peru is also famous for Lake Titicaca, the world’s most navigable lake, with rich cultural heritage, Manu National Park, with harpy eagles, cock-of-the-rock, capybaras, and poison dart frogs, as well as Machu Picchu and the Sacred Valley.
Ecuador
Ecuador is part of the Tumbes-Chocó-Magdalena hotspot, which extends along the Pacific coast and includes dry forests, coasts, mangroves, and the lush Chocó-Darién rainforests. This region is home to distinctive wildlife, including spider monkeys, bare-faced tamarins, and rice rats.
Ecuador’s mangrove ecosystems are especially notable but highly endangered, with only a small fraction of their original extent remaining. Efforts are underway to protect these vital ecosystems, which are crucial for biodiversity and local communities.
The small but incredibly biodiverse country is famous for the Galápagos Islands, with giant tortoises, marine iguanas, and Darwin’s finches (which were one of the key inspirations to the theory of evolution).
Australia
Australia boasts incredibly high levels of endemism—around 87% of mammals, 93% of reptiles, and 45% of birds are found nowhere else on Earth, including iconic species like platypuses, koalas, and kangaroos.
From vibrant coral reefs to expansive woodlands and the world-famous Great Barrier Reef, the country supports over 24,000 plant species and a wide array of unique ecosystems.
Southwest Australia is one of the world’s oldest biodiversity hotspots, covering over 356,700 square kilometers and featuring a Mediterranean-style climate. Like the lush forests of Eastern Australia, it harbors specialized ecosystems such as eucalyptus woodlands and kwongan heathlands. Stretching from the Esperance Plains in the south to Shark Bay in the north, the country is home to numerous endemic species, including the remarkable salamanderfish.
India
India is home to several incredible biodiversity hotspots, including the Himalayas, Indo-Burma, Sundaland, and the Western Ghats, each teeming with unique ecosystems and iconic species such as the Bengal tiger, Asian elephant, and Indian rhinoceros.
Traditional conservation practices, like those found in sacred groves, play a crucial role in preserving India’s biodiversity. These groves, scattered across the country, safeguard endemic species and micro-ecosystems. For example, the Khasi Sacred Groves in Meghalaya shelter an extraordinary variety of plants, orchids, fungi, and rare medicinal herbs.
The Western Ghats, a UNESCO World Heritage Site, extend into the highlands of Sri Lanka, forming a stunning landscape of wetlands, lush rivers, and dense forests. This region alone harbors an incredible 4,000 flowering plant species and 500 bird species.
China
China is 9.597 million kilometres; the third largest country in the world by area, and over 12 different types of ecosystems—including deserts, tropical rainforests, grasslands, subtropical forests, freshwater ecosystems, and tundra ecosystems.
China’s biodiversity is exemplified by the Mountains of Southwest China, which span parts of Yunnan, Myanmar, Western Sichuan, and southeastern Tibet. The nation features a wide variety of landscapes, from towering mountain peaks to lush river valleys, with habitats ranging from alpine meadows to temperate and subtropical forests.
Notable wildlife in this region includes the giant panda, snow leopard, and the rare Gaoligong pika, reflecting the area’s extraordinary species richness and endemism.
Madagascar
Madagascar is frequently referred to as the eighth continent due to its sheer diversity of flora and fauna. In the southeastern coast of Africa in the Indian Ocean, an amazing 90% of Madagascar’s wildlife is endemic.
Tropical rainforests, mangroves and coasts, dry deciduous forests as well as spiny forests make up a complex network of ecosystems, with remarkable species like lemurs, the fossa, and baobab trees.
Philippines
An archipelago of over 7,000 islands, the Philippines is a stand-out hotspot for biodiversity in Southeast Asia.
The major regions like Palawan, Mindanao, and Luzon, are each packed with their own diverse landscapes, ecosystems, and endemic species.
Their waters have some of the highest levels of marine biodiversity, with over 500 coral species and 1,600 fish species.
An outstanding example of Philippine nature are the chocolate hills in Bohol—a group of over 1,200 to 1,700 conical hills which turn brown in the dry season, resembling chocolate. Each hill is similar in form, and from 30 to 120 metres high.
Malaysia
Some of the oldest rainforests in the world are located within Malaysia, such as Taman Negara, home to tapirs, tigers, and sun bears, and high levels of both terrestrial and marine endemism, making it critical for biodiversity conservation.
There are many notable examples of Malaysian nature, from Malayan tigers to the Langkawi mangroves, but incredibly striking is the rafflesia—the biggest (and stinkiest) flowering plant in the world, with the largest recorded over 3 feet in diameter and 20 pounds.
United States
The United States’s sheer size makes it one of the most biologically diverse countries in the world. For reference, the UK could fit into the US around 40-45 times.
From the Everglades to Yellowstone, the US has ecosystems for nearly all climate zones, and is estimated to take up nearly 13% of the world’s species with over 200,000 native.
Venezuela
Venezuela is home to some of the most magical nature in the world, with the Amazon Rainforest, Andes Mountains, Llanos grasslands, and Caribbean coastlines.
Amazingly, in Venezuela you can find tepuis—breathtaking tabletop mountains that rise dramatically from the surrounding landscape, their sheer cliffs shrouded in mist. These ancient formations harbour specialized ecosystems with endemic species, including carnivorous plants and amphibians such as the pebble toad.
Papua New Guinea
Papua New Guinea has tropical rainforests, coral reefs, wetlands, savannas, rugged mountains and more. Its landscapes are teeming with life, hosting thousands of unique species found nowhere else on Earth.
A notable example is the Sepik River, one of the longest rivers in the world without a dam, at about 1,100 kilometers. Along this, there are swamps, tropical rainforests, floodplains, and a range of micro-habitats each supporting unique and rich wildlife.
Thailand
Thailand has stunning mangroves, montane forests, coral reefs, and tropical rainforests amongst a range of vast, thriving ecosystems. These are home to iconic wildlife such as the Indochinese tiger, Malayan tapir, hornbills, the Siamese crocodile and thousands more.
Part of the Coral Triangle; Thailand boasts vibrant reefs alongside sea turtles, manta rays, and whale sharks.
Democratic Republic of Congo
The Democratic Republic of Congo (DRC) is often called the “Heart of Africa” due to its immense size and unmatched biodiversity. Located in central Africa, the DRC contains over 60% of the Congo Basin Rainforest, making it home to one of the world’s largest tropical rainforest systems.
This vast country boasts a rich array of ecosystems, including dense rainforests, savannas, swamp forests, and montane habitats in the Virunga Mountains. The DRC is famous for endemic species such as the bonobo, okapi, and forest elephant, as well as gorillas, chimpanzees, and vibrant birdlife.
South Africa
The Cape Floristic Region is one of the planet’s most substantial locations of terrestrial biodiversity, located in southwest South Africa. Spanning around 90,000 square kilometres in land surface, it’s highly notable for its immense plant diversity as well as endemism.
Its unique fynbos ecosystem is characterised by shrublands adapted to the Mediterranean climate; typically hardy, small-leaved plants.
Guinea
The Guinean Forests of West Africa, which stretch from Guinea and Sierra Leone to Cameroon, include some of Guinea’s most biodiverse regions. These dense tropical forests, interspersed with swamp forests, savannas, and rainforests, are critical for the country’s ecological richness.
With high humidity and significant rainfall, Guinea’s portion of this forest belt is home to numerous species, including some of the 2,250 endemic plants and unique animals like chimpanzees, pygmy hippos, and forest elephants. The forests also support over 900 bird species and nearly 400 terrestrial mammals, making them a vital part of West Africa’s biodiversity hotspot.
Costa Rica
Costa Rica features volcanic mountains, tropical dry forests, cloud forests, coral reefs, and more. It’s estimated that the country contains around 5% of the world’s biodiversity, within just 0.03% of the Earth’s land area.
A beautiful example of Costa Rican nature is the Arenal Volcano, a striking volcano amidst the Arenal Volcano National Park and nestled within tropical rainforests. The volcano was highly active in the recent past, and even equipped regularly from 1968 to 2010.
More Information
https://www.activesustainability.com/environment/top-10-countries-in-biodiversity/
https://worldrainforests.com/03highest_biodiversity.htm
https://worldostats.com/tag/most-biodiverse-countries-in-the-world
https://news.mongabay.com/2016/05/top-10-biodiverse-countries/
https://acis.com/blog/5-of-the-most-biodiverse-countries-in-the-world/