Orinoco Basin. Plains of Venezuela - 3

In Venezuela there is an immense plain called the Orinoco basin. This place passes every year through droughts and floods and therefore has a great biological diversity.

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Venezuela is the land of the tepuis and of exotic beaches.  But inland there is another treasure of nature, still largely undiscovered – the basin of the Orinoco, lying between the Andes to the west, the coastal mountain range to the north and the Guyana massif to the south-east.  It is so completely flat that it has been named the ‘Region of the Plains’.
Almost all the rains fall in a single season, and so the ecosystem of the plains alternates between extremes of flood and drought.  It is a land of contrasts, a little-visited paradise of surprisingly rich and varied fauna and flora.


The Apure river runs across the plain, flanked by thick vegetation.  Here, ever alert, lives the wood ibis, also know as the American ibis or forest stork.  Every year they build their nests along the banks of the river and feed on the animals that live in its waters.

In the water, the alligators and the piranhas.
Most of the soil on the plains is clay, which prevents drainage.  With the coming of the rains, the level of the rivers rises and, because the land is so flat, and the soil non-porous, many marshes are formed.  The majority of them will disappear in the dry season.  As the ground is flooded, the seeds that had been left buried in the mud the year before spring to life, covering the waters in dense vegetation.  


Water hyacinths rapidly coat the surface of the lagoon.  
The hyacinths don’t bury their roots in the soil, but rather float, feeding on the nutrients carried along by the water.  In this way, they can drift with the current, and so easily colonise new territories.
The lack of roots is an advantage not only for the plants.  It also means that fish and reptiles can move about freely below the surface of the water.  Like the anaconda.

The number of water hyacinths is kept in check above all by this rodent, the capybara.
 The capybara, weighing in at fifty kilos, is the largest rodent on earth.
After a gestation period of four months, the capybaras give birth to between two and eight young.  The mating season is timed to ensure that they are born at the end of the rainy season, when conditions are at their best, and the chances of survival greatest.  Around 50% do survive, which gives us some idea of the demographic potential of these rodents.

The dry season is also a time of plenty for the alligators.  As water becomes scarce, the pools shrink, the fish are trapped and so are easy to catch.

The forests along the banks of the rivers are home to one of the strangest birds in the world, the hoatzin.
The hoatzin is totally unique.  It is so extraordinary that it is believed to be related to the archaeopteryx, the oldest pre-historic bird known to man.  It is herbivorous, living almost exclusively on the young shoots, leaves and fruit of two trees, the arum and the white mangrove.  

So, the tributarieas of the Orinoco offer both protection and food.  These waters form the marshes, and are the real source of life here on the plains, the guarantee that this will remain in the future what it is today, a paradise in the centre of Venezuela.

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