The Medes Islands are today one of the most important marine flora and fauna reserves in the western Mediterranean.
Vegetation conditioned by the environment.
The Mediterranean climate includes long periods of drought often coinciding with the heat of the summer. The dry land cannot then easily absorb water and, when it rains, a lot of the water slips away through the cracked earth. In response to this, plants like the prickly pear and the rest harrow contain water reserves that enable them to survive in the driest places. The prevailing Tramuntana north wind and Garbí south west wind carry drops of salt sea water to the islands, where the vegetation includes shrubby sea-blight plants that eliminate excess salt through their leaves. Caucus gingili and rock sapphire are other salt-resistant plants.
On the other hand, the island flora was modified by man by the introduction of exotic species such as agaves and the tree of heaven.
An impoverished fauna?
The yellow-legged gull is undoubtedly the most common species on the Medes Islands, home to the largest colony in the Mediterranean. However, the sheer numbers of gulls may mask the presence of other interesting bird species, such as the large colony of ardeidae (cattle egrets, little egrets and night herons), the second largest of its kind in Catalonia. On the islands we also find peregrine falcons, pallid swifts, alpine swifts and blue rock thrush, among other bird species, and in the rock pools there is a small colony of common European shag. Nevertheless, it must also be said that the true inhabitants of the islands are the many different species of insect, with the mallow bug as the most significant.
The Medes Islands and the Montgrí Massif are both part of the same geological unit.