Islands boast some of the most diverse collections of plants and animals on Earth. With a unique set of influences and conditions, island life has evolved in a very different way from life on larger landmasses.
The Convention on Biological Diversity aims to bring these island ecosystems to the public's attention. The annual International Day of Biological Diversity (which falls on May 22), raises worldwide awareness about biodiversity, from its many benefits for people to the variety of places — like islands — where it tends to thrive.
These 11 islands provide a living definition of biological diversity. Few other landmasses can match the uniqueness of their plant and animal species.
The Pinnacles are limestone spikes in Mulu National Park, Borneo. (Photo: Paul White/Flickr)
The world's third largest island, Borneo has about the same land area as the state of Texas. Divided among Malaysia, Indonesia and the tiny sultanate of Brunei, the isle has more than 200 species of mammal, 44 of which are endemic (meaning they are found nowhere else in the world). About 6,000 of Borneo's plant species are also endemic. The most striking biodiversity statistic comes from the dipterocarp trees of Borneo's rain forests: More than 1,000 species of insect can be found in a single tree.
Lake Toba is a massive volcanic lake in Sumatra. (Photo: Max Grabert/Flickr)
This island in westernmost Indonesia contains more than 185,000 square miles of land. Despite being home to more than 50 million people, Sumatra boasts a stunning array of wildlife. The inland jungles of Sumatra are home to a rare combination of species. This is the only place on Earth where tigers, rhinos, elephants and orangutans live wild in the same ecosystem. Aggressive conservation efforts aim to protect these species, especially the endemic Sumatran tiger, whose numbers are estimated at fewer than 400.
Coquerel's sifakas are among the types of lemurs that populate Madagascar. (Photo: Frank Vassen/Flickr)
The Indian Ocean nation of Madagascar, the world's fourth largest island, defines biodiversity like no other island on Earth. An almost unbelievable 90 percent of its plant life is endemic. Some mountaintops in the Malagasy highlands are the only places where certain plant species grow. Of course, the lemur is the most famous only-in-Madagascar animal; 72 types of lemur species and subspecies live on the island.
A gannet colony nests at Cape Kidnappers on the North Island of New Zealand. (Photo: Mike Locke/Flickr)
New Zealand is made up of two main landmasses — North Island and South Island. Its diverse landscapes are well-known thanks to Kiwi director Peter Jackson's "Lord of the Rings" movies. Each of New Zealand's ecosystems is filled with endemic species. All native bats, reptiles and amphibians are found nowhere else on Earth, and 90 percent of the freshwater fish are endemic as well. A great example of New Zealand's nature is its fungi population. Less than one-third of the estimated 20,000 species of fungi in New Zealand have even been categorized.
Mossy trees line the Overland Track bush walk in Tasmania's Cradle Mountain-Lake St. Clair National Park. (Photo: Tatters/Flickr)
Sitting to the south of mainland Australia, Tasmania is one of its country's most important biodiversity hotspots. The most famous of this island's creatures is the Tasmanian devil, considered the world's last surviving carnivorous marsupial. Among the island's native plants, the Huon pine grows very slowly but can live for 3,000 years. The endemic pandani, a prehistoric-looking palmlike tree, dominates the wet subalpine climes of Tasmania. Platypuses, penguins, parrots and the rare eastern quoll are also part of this island's diverse animal population.
Golden jellyfish are among the rich biodiversity of Palau. (Photo: amanderson2/Flickr)
The tiny Micronesian nation of Palau, only 170 square miles, is rich in wildlife both on land and in the water. Palau's coastal areas have a high concentration of marine life, including crustaceans and corals. The unusual dugong, a relative of the manatee, can be found in large numbers in Palau's coastal shallows. The island chain also has great diversity when it comes to its freshwater fish population, including four endemic species. Among Palau's unique creatures are its stingless jellyfish. Swimming in saltwater lakes connected to the sea only by tunnels and caves, these creature have lost their ability to sting because they have no natural predators.
A guitarfish swims in Coiba National Park. (Photo: Laszlo Ilyes/Flickr)
Sitting off Panama's Pacific coast, Coiba is a large Central American island. A number of subspecies have evolved here with almost no human contact. The Coiba howler monkey is the most famous of these endemic animals. Island wildlife thrived here for a very unusual reason: Until 2004, a notorious Panamanian prison was operated on Coiba. Because of this, few civilians ever visited the island, and more than 75 percent of the land is still covered with virgin forests. One of the largest coral reefs on the entire Pacific Coast of the Americas sits near Coiba as well. More than 700 species of fish have been recorded in these marine habitats.
South Georgia Island
King penguins inhabit St. Andrews Bay on South Georgia Island. (Photo: Liam Quinn/Flickr)
The islands of Antarctica are the last place you would expect to find biodiversity. But researches have been intently studying remote South Georgia Island and have found as much biodiversity here as on the famous Galapagos. A survey found 1,445 marine species living in South Georgia's coastal waters. Bizarre creatures like free-swimming sea worms, icefish and sea spiders live here. Massive penguin populations dominate South Georgia’s shores, while 90 percent of the world's fur seals use the island as a base, as do about half of the Earth’s population of elephant seals. In all, 1,500 species call the cold waters and icy lands of South Georgia Island home.
These famous Ecuadorian islands straddle the equator in the Pacific Ocean. Charles Darwin came here in the 1830s and returned with solid evidence to support his theories about evolution. Many of the animals that inspired his findings still thrive here. The Galapagos land iguana, the unique marine iguana that hunts in the sea, the Galapagos tortoise, the flightless cormorant and a huge number of endemic finches (collectively referred to as "Darwin's finches") call these islands home. It is not uncommon to find several species occupying the same small piece of shoreline.
The Vinales Valley of Cuba is home to many endemic species of plants and animals. (Photo: Romtomtom/Flickr)
Cuba's political and economic isolation mean that relatively little is known about its wildlife. However, a number of species thrive in the island's unique combination of ecosystems. The Zapata Swamp is a great example of Cuba's biodiversity. The largest wetland in the Caribbean, Zapata is home to the Cuban crocodile. In addition to this endemic reptilian predator, the swamplands have flocks of picturesque flamingos, several endemic bird species, and hundreds of unique plants and insects. Cuba's overall geographic diversity — wetlands, inland savannas, mountains, arid coastal areas and tropical rain forests — have created a unique set of ecosystems, each of which is filled with endemic life.
Sea lions are plentiful on California's Channel Islands. (Photo: Michele W/Flickr)
Eight islands are part of California's Channel Islands archipelago, which sits a short distance from the city of Santa Barbara. Five of these landmasses, as well as the waters between them, are part of the Channel Islands National Park. Endemic bird species like the island scrub jay are found only on Santa Cruz Island, the largest of the Channels. Bats and unique subspecies of mouse and fox are among the national park's terrestrial inhabitants, though much of the biodiversity is found in the ocean waters between the islands. Seals, sea lions, whales and dolphins all share the waters around these islands. Coming to breed and to feed, these sea mammals are a big draw for nature-seekers.