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Thursday, January 14, 2010

Biodiversity in Southern Orinoco Delta



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There is no doubt that growing human pressure is an hazard for biodiversity worldwide. This is very much clear to all those who watch natural events with some care. Recently I came across the case of rainforest amphibians as, in particular, I had the great chance to spot and observe a poison frog which generally lives in eastern Amazon, the Dendrobates tinctorius .


Amphibians skins easily absorb pollutants and are scarcely protected against UV radiation. Moreover, droughts may be lethal for their reproductive cycles as tadpoles are placed by frog males in moist tree holes with some preference for vase bromeliad plants. On the other hand frogs are very much aware that toxins secreted by their skin are a tremendous self-defense tool. Thus they don't need to camouflage so much and rather proudly display their beautiful colors which sound as a warning for potential predators. Indigenous people have recognized since long the power of frog skin poison and use it on the tips of arrows and darts. The biochemicals yielded by skin secretions are under investigation for potential use in medicine.


I am grateful to Mr. Roger Ruffenach who invited me at his Campamento Oridelta situated in Piacoa, a village in the southern part of the Orinoco river Delta (Venezuela). It has been a gorgeous experience as Roger and his wife are exquisite persons. Roger is a true environmentalist whose competence regarding flora and fauna of that region is likely unrivaled. He took me by boat along the amazing Caños which flow eastward and further away encounter the Ocean in an almost unexplored area towards the British Guyana.

I strongly recommend to spend some time at Roger's place in order to learn about tropical ecosystems.

The whole Orinoco delta, which extends over about 28000 square kms, is a peculiar biosystem in itself and, on its southern fringes, it leaves room to the rainforest environment characterized by much taller canopy trees. Precisely in this interesting border zone between Delta and rainforest I could spot the poison frogs. A few months ago UNESCO declared about one third of the Orinoco Delta to be a Biosphere World Reserve.

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