HOW THE RAIN FOREST WORKS

Tropical Rain Forest is the most complex ecosystem on earth! It produces about 2.000 grams of dry plant material per Km2 per year, compared with 1.250 grams per Km2 for a temperate forest. It is an association of producing, consuming and decomposing organisms, all ultimately deriving their energy from sunlight. The producers are the plants, the consumers are the animals, and the decomposers consist of bacteria, fungi and certain small animals like millipedes and termites, which break down dead organic material so that minerals, carbon, nitrogen and other important elements can be recycled.
The crowns and foliage of the rain forest trees form several strata or stories. A major division exists between the canopy, which is exposed to almost full sunlight, and the undergrowth, which is much less brightly illuminated. There is, therefore, a strong contrast between the microclimate of the canopy and that of the strata closer to the ground, as well as intermediate microclimates at middle levels.
Of all natural terrestrial ecosystems, none accomplish more photosynthesis than tropical rain forest. The energy obtained from the conversion of the sun’s rays into plant structural material is then cycled through the ecosystem by plant eaters such as various insects, birds, and mammals. These herbivores are able to convert no more than 10% of what they eat into usable energy while the other 90% is either excreted and later recycled by decomposers, or lost as radiated heat as the result of the animal’s metabolism. The same thing happens when a carnivore eats an herbivore; at each step only 10% of stored energy is used by the consumer, and the rest is released back into the system. This is why there are many more plants than plant eaters, and many more plant eaters than animal eaters, and so on up through the rare top carnivores such as the jaguar or harpy eagle, which need very large territories just to gain enough energy to survive, grow, and reproduce.
It is one of the paradoxes of tropical ecology that the rain forest survives only by maintaining an almost closed nutrient cycle. A large fraction of the available nitrogen, calcium, phosphorus, potassium and other materials is held in the vegetation itself. Even though the total stock of available nutrients is not large, recycling is rapid, efficient and very little is lost from the system itself.
In western Amazonia, including the forests around Kapawi, one hectare can support up to 300 tree species, and most species are rare (each with only 1 or 2 representatives in our sample hectare). Compare this to temperate forests, where as few as 2-5 tree species may be present with 1 or 2 species dominating the rest. Of course there are thousands of other plant species contributing to the high plant diversity, and this incredible abundance in turn underlies high diversity of animal species. For instance, there are 570 confirmed species of birds just in the Kapawi area while only 200+ exist in all of the continental U.S.!