Millions of years of evolution, a stable climate, and a constant abundance of resources have turned rainforests into true sanctuaries of life. Despite covering only a small part of Earth’s surface, these forests contain more than half of the world’s known biodiversity. Behind this exceptional richness lies a natural system that is both remarkably complex and extremely fragile.
Article and photographs by Damien Lafon.
A Warm and Stable Climate All Year Long
The tropical climate is one of the main explanations. Near the equator, temperatures change very little throughout the year. In many rainforests, average temperatures remain between 24 and 28 °C. In addition, rainfall often exceeds 2,000 mm per year. This stability supports life. Unlike temperate regions, tropical forests have experienced very few major climatic disruptions over millions of years. As a result, species have had more time to evolve and specialize.
Almost Permanent Plant Growth
Thanks to heat and humidity, plants grow throughout the entire year. Trees continuously produce leaves, fruits, and flowers. This abundance supports a massive food chain. Insects, birds, reptiles, and mammals can easily find resources. Moreover, scientists estimate that one hectare of Amazon rainforest can host several tens of thousands of insect species. This biological richness then attracts even more predators and specialized species.
A Forest Organized on Several Levels
Rainforests have a very unique structure. Unlike other forests, they function almost like natural skyscrapers.
They are generally divided into:
- emergent trees
- the canopy
- intermediate layers
- the understory
- the forest floor
Each level has its own light and humidity conditions. Therefore, different species can live within the same space without directly competing with one another. Some frogs live only high above the ground. Other species remain close to the humid forest floor.
Did You Know?
The canopy alone contains around 70% of tropical rainforest biodiversity.
Competition That Accelerates Evolution
In rainforests, species constantly compete with one another. They search for light, food, and territory. This pressure pushes animals and plants to develop highly specialized adaptations. For example, some insects perfectly imitate dead leaves. Certain orchids attract only one specific pollinator. Other plants produce toxins to protect themselves from predators. Over time, these adaptations encourage the appearance of new species. Scientists call this process speciation.
Tropical Rainforest Biodiversity Is Still Largely Unknown
Despite scientific progress, a large part of tropical species remains unknown. Today, around 2 million species have been officially identified on Earth. However, some estimates suggest that between 8 and 15 million living species may exist worldwide. Rainforests likely contain a large part of this still-hidden biodiversity.
Researchers regularly discover:
- new insects
- amphibians
- plants
- fungi
- microorganisms
Some remote regions of Borneo or Papua remain very poorly studied.
Invisible Relationships Between Species
Tropical forests function through an extremely fragile balance. In reality, many species directly depend on one another. Some trees rely on specific animals to spread their seeds. Certain flowers depend on a single insect species for pollination. As a result, the disappearance of one species can trigger several chain reactions. This complexity explains why scientists consider rainforests to be major ecosystems for global balance.
Did You Know?
A single tropical tree can sometimes host several hundred different insect species.
Forests Essential for the Global Climate
Rainforests do not only protect biodiversity. They also play a central role in the global climate. Trees absorb large amounts of carbon dioxide. They also help regulate rainfall and temperatures. However, deforestation is rapidly increasing in several tropical regions. Every year, millions of hectares disappear because of logging, intensive agriculture, and mining activities. Consequently, many species risk disappearing before they are even studied.
Why Do Rainforests Fascinate Scientists So Much?
Tropical forests represent one of the most complex biological systems on Earth. Their stable climate, vertical structure, and millions of years of evolution have allowed exceptional biodiversity to develop. Observing a rainforest therefore means observing a vast living natural laboratory. Behind every tree, every insect, and every vine lies a biological mechanism that remains largely misunderstood.
FAQ
The warm, humid, and stable climate encourages the evolution and specialization of species over millions of years.
The main tropical rainforests are found in the Amazon, Central Africa, and Southeast Asia.
The canopy concentrates a large part of the light and biodiversity found in tropical rainforests.
Yes. New species are regularly discovered in tropical rainforests.
Deforestation, mining, and intensive agriculture are severely damaging these fragile ecosystems.
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