Rainforest’s are some of the most diverse, yet primitive, ecosystems found anywhere on the planet. They are believed to comprise over 90% of the biology species known, and at least 60% of those species are epiphytic, some say as much as 80%. Epiphytes, also frequently referred to as air plants, grow everywhere in this environment, from covering the canopy to clinging to rocks to living in the bark trees. Why do epiphytes grow so well in the rain forest?
Before answering the question of why epiphytes grow in the rainforest, let’s first define both epiphytes and a rainforest. Epiphytes are plants that have no true root systems and live primarily off nutrients from the air. The do no harm to the “host” plant that they are living on and can be beneficial. A rainforest is a complex ecosystem that has high humidity and gets a tremendous amount of rain. They are found mainly between the Tropic of Capricorn and the Tropic of Cancer, near the equator.
Epiphytes grow in rainforests for several reasons. One of the main reasons is that rainforests are stable, uniform environments. Temperature and humidity rarely change and lighting is fairly constant. Why is this important for an epiphyte? It means less problems with food storage because food is always available at a constant rate. Epiphytes have little or no true root systems and roots are not just for moisture absorption, but energy storage. The constant high humidity means no drying out, and extra water isn’t needed, it is taken straight from the air by the leaves and tendrils.
Epiphytes also frequently rely on other plants or specific creatures that may only be found in the rainforest, and sometimes in very specific places in the rainforest! Each species of orchid is only pollinated by one species of insect, that insect has the right shape and tongue for the flower, so the orchid must grow where the insect lives, and most of those insects can only survive in the rainforest.
This relationship is called symbiosis and is why rainforest ecosystems can be damaged so easily. Eradicate the insect and eradicate the epiphyte. The epiphyte may be essential for some bird which spreads seeds for some other plant. Destroying something minor, such as termites, can wipe out as much as 20% of the species of plants and in animals in some rainforests!
In summary, epiphytes grow in rainforests because it is the best place for many of them to live. It has stable conditions and supporting plants and creatures which the epiphyte needs.