The archipelago of Galápagos has once again just delivered a secret. Six kinds until then considered to be immigrants have just got their birth certificate. He is published in the magazine Science of November 21st, 2008 by an international team (Switzerland, Great Britain, Ecuador and Norway).

In the archipelago of Galapágos, a shelter for an unique fauna and a flora, the preservation of environment passes by the abolition of kinds introduced voluntarily or accidentally since the discovery of these lands. The Ecuadoran authorities spend millions of dollars every year to eliminate them. Jobs published in Science should reduce task a bit. Six kinds of plants had been classified alien wrongly. The analysis of pollens preserved in layers of sediments of marsh of the island of Santa Cruz proves that this vegetation was present long before the arrival of the European, in 1535 (1). So, the researchers found the pollen of ageratum conyzoides, the grass to billy goat (2), whom datings make go back up in at least 5400 years. Also, diversifolius hibiscuses was not only considered as foreign in the archipelago, but also classified invasive by the Base of data of the plants which threaten the ecosystems of the Pacific. His current extension would be therefore the consequence of a reconquest of areas lost in the course of last centuries.

The researchers do not specify if one had being aimed by the operations of restoration in the reservation of Galapagos at six reclassified plants. They explain nevertheless that not much spread kinds are considered to be targets of choice for the programmes of eradication. Ranunculus flagelliformis, who was discovered only in 1972 because of the curiosity, will she have been victim of an error of evaluation which made her classify as plant introduced by the man?

(1) The three centuries later, a young British man, Charles Darwin passed to it one month. He will draw the theory of evolution.

(2) She draws her name of the strong smell which frees when it is crushed.

Picture: The marsh Psidium of the island of Santa Cruz, in Galapagos © Science-AAAS