From lush rainforests to towering mountains, some regions of Earth are irreplaceable. Many of these regions are biodiversity hotspots—areas that are both rich with life and at high risk for destruction.

Biodiversity hotspots make up only about 2.5% of Earth’s land surface, yet they are home to more than half of the world’s plants and 43% of land vertebrates. Most plants in a biodiversity hotspot are endemic, meaning they are not found anywhere else on Earth. Biodiversity hotspots are, by definition, in a conservation crisis. To be classified as a biodiversity hotspot, a region must have lost at least 70% of its original natural vegetation, usually due to human activities and influences. For example, clearing forests for lumber and agriculture or introducing invasive species (non-native species that harm the local environment) can contribute to this vegetation loss.

There are 36 biodiversity hotspots recognized by Conservation International, an organization that protects nature and biodiversity around the world. Many hotspots are islands, including the New Zealand archipelago. Life on New Zealand evolved for 80 million years in isolation, far from other land masses, so the islands contain many species not found anywhere else. More than 90% of the insects and 80% of the vascular plants in New Zealand are endemic to the region. The Indigenous Māori people have been preserving this environment for centuries. They are currently working to protect the island’s biodiversity from climate change and invasive species introduced by European settlers in the 19th century. Other island biodiversity hotspots include Japan, Madagascar, the Philippines, the Caribbean islands and New Caledonia (the world’s smallest hotspot).

There are also non-island biodiversity hotspots. Some are vast, forested regions, such as the Atlantic Forest of South America and the Coastal Forests of Eastern Africa. Others are rugged, mountainous areas. The Tropical Andes hotspot, a part of the Andes mountain range that extends from western Venezuela to northern Chile and Argentina, is the most diverse hotspot in the world. About one-sixth of all plant species in the world live in this region. The Himalaya hotspot of South Asia contains the tallest mountains in the world, (including Mount Everest), as well as unique animals like the snow leopard (Panthera uncia), the red panda (Ailurus fulgens) and the black-necked crane (Grus nigricollis)—the only alpine crane in the world.

Deforestation and climate change are causing habitat loss for the unique plant and animal species of the Himalayas and other biodiversity hotspots. People and companies cut down trees and burn all the vegetation to clear large areas of land to obtain lumber, raise livestock or grow crops, such as soybeans or palm oil. Palm oil is used in many food products. Illegal palm oil plantations are causing massive deforestation in the Leuser Ecosystem—the last place on Earth where Sumatran rhinos (Dicerorhinus sumatrensis), Asian elephants (Elephas maximus), tigers (Panthera tigris) and Sumatran orangutans (Pongo abelii) coexist in the wild.

Deforestation hurts the local, Indigenous people living in biodiversity hotspots who depend on their natural resources for food, medicine and fuel. More than 50 Indigenous groups live in the Tropical Andes hotspot, where they occupy more than one-fifth of the land. Indigenous people have used rainforest plants for medicinal purposes for centuries, but habitat loss from deforestation may cause many known endemic medicinal plant species to go extinct. Other species may go extinct before scientists have studied their potential use as drugs to treat diseases. The loss of plant life not only impacts local communities, but also people around the world.

Climate change—the rise in global temperatures caused by the burning of fossil fuels and worsened by deforestation—is also a major threat to Earth’s biodiversity. The risk of extinction due to climate change is highest for species in biodiversity hotspots, according to the Intergovernmental Panel on Climate Change (IPCC). Climate change is caused by the release of greenhouse gases, like carbon dioxide from burning fossil fuels, into Earth’s atmosphere. Deforestation worsens these effects because trees and plants help regulate climate. They remove carbon dioxide from the atmosphere and store carbon in their roots and leaves.

Planting trees and restoring forests can help reverse the negative impacts of deforestation. In the Himalaya hotspot, local people are working with conservation organizations to plant millions of trees. Indigenous communities in Peru are using satellite images to monitor their forests and reduce tree loss. Brazil has committed to replant 12 million hectares (29.6 million acres) of native vegetation as part of the Bonn Challenge, a global project that aims to restore 350 million hectares (875 million acres) of degraded land by 2030.

Establishing legally protected areas can also help protect life in biodiversity hotspots. Bhutan, a country in the Eastern Himalayan mountains, for example, has protected areas that include nine biological corridors that connect forest habitats for threatened species. This allows animals to move among different areas safely.