Discover how many tropical rainforests exist around the world and explore their biodiversity
How many rainforests are there in the world – and just what’s so special about them? Uncover the hidden secrets of these special habitats
Tropical rainforests are almost mythical places to those of us living in more temperate climes. We are inclined to see them as a sort of ecological gold standard, as gardens of creation, or even paradise on Earth, yet most of us will never visit one.
There is perhaps such a thing as too much nature on holiday. Biodiversity includes creatures that bite and sting, and tropical rainforests have plenty of both.
What are rainforests and why are they called rainforests?
And then there is the weather. No surprise there, of course – the clue is in the name. Rainforests are defined by the vast quantities of water that fall on them. The forests cladding the lower slopes of Mount Cameroon in West Africa receive more than 10m of rain every year. (The wettest parts of the UK get about 3m.)
Being close to the equator, they are hot, too. And heat and water combine to produce uncomfortable humidity. The result is that we are mostly content to revere them from afar.
How many rainforests are there?
The question of how many rainforests there are is a tricky one. In an age when natural habitats are becoming increasingly fragmented, more is not necessarily merrier. Better, perhaps, to think in terms of the area of land they occupy. Tropical rainforests occur in West and Central Africa, Central and South America, South-East Asia and north-east Australia. Together, they cover an area of about one billion hectares (ten million km²), which is about seven per cent of the world’s land area.
What animals live in a rainforest?
An eye-wateringly large number of species live in this relatively small space. Precise numbers are hard to pin down when most of the world’s species are yet to be described by science. But we know, for example, that about 56 per cent of all the world’s terrestrial vertebrates live in tropical rainforests.
So why are they so full of life? It might be due to the relative stability of the tropics in terms of geological and meteorological processes. Temperatures are pretty constant throughout the year and equatorial regions have been spared the ice ages that intermittently scour life from the landscape at higher latitudes.
Extinction rates have therefore been relatively low throughout much of their history. Meanwhile, high tropical temperatures are thought to speed up biological processes and the creation of new species.
Are there rainforests in the UK?
Not all of the world’s rainforests are tropical. The term ‘temperate rainforest’ is increasingly used to describe the lush, rain-drenched woodlands found along the Atlantic coast of northern Europe and the Pacific coasts of North America and Eurasia.
England’s largest temperate rainforest, Borrowdale in the Lake District, has been declared a national nature reserve in a bid to protect it for centuries to come. While a temperate rainforests’ structure is similar to that of their tropical namesakes, they cannot compete in terms of species richness. Though it’s still worth packing the midge repellent.
Journey into Britain’s forgotten rainforests with The Lost Rainforests of Britain author and environmental campaigner Guy Shrubsole