Ilhas Selvagens (Selvagens Islands)

Description

The Selvagens. comprised by Selvagens Grande. Selvagem Pequena and Ilhéu de Fora were discovered by the Portuguese in the XV century. (1438) and remained practically unhurt by all attempts to colonize it, and they remained inhospitable and uninhabited up to the present time. Selvagens Grande (SG) has a very rugged landscape and a coastline of sliccr drops resulting from natural erosion and only one or two safe anchoring places. It is crowned by a plateau that is approximately 100m above sea level. Selvagem Pequena, which is very irregular in shape, is low lying, flat and almost entirely covered in calcareous sand, where there are depositions of sea said on the seabed of bays formed by plateaus of erosion. Ilhéu de Fora is even lower and similarly, covered in calcareous sand. These islets represent the remains of volcanic peaks and it is interesting to note that their area is almost double at low tide. Geologically, the Selvagens are oceanic islands of volcanic origin. These islands are subject to a subtropical maritime climate. As is the case on Madeira, they are under the influence of dominant northeasterly winds, the trade winds, however, their low altitude does not favor cloud condensation, which is responsible for lower precipitation levels than those for Madeira. Sometime in the p these islands must have been subjected to much higher humidity conditions, which can be inferred from the presence of a great profusion of sub-fossil shells of land snails. Selvagens constitute an important area in the Atlantic for the nesting of pelagic marine birds. hi the case of Cory's Shearwater which is no doubt the ex-libris of Selvagens, its actual population is estimated at approximately 40.000 birds, 14 000 being the number of reproductive couples calculated. This species constitutes the largest colony on Selvagens, and probably one of the most important worldwide. Cory's Shearwater is not, however, the most numerous bird on Selvagens. The White-faced Petrel Pelagodroma marina hypoleuca, forms a colony of around 19 000 couples. Bulwer's Petrel, the Madeirean storm petrel and the Little Shearwater are other marine birds that also nest on Selvagens, although in effect very much smaller in number than the White-faced Petrel or Cory's Shearwater. As resident birds we find Berthelot's Pipit, Anthus bertheloti bertheloti on Selvagens, the saine subspecies present in the Canary Isles, and a reduced number of couples of the Kestrel, Falco finnunculus canatiensis. True as it may be that the Selvagens Nature Reserve is of ornithological value, its very evident heritage in terms of flora is no less important, mainly on Selvagem Pequena and -Ilhéu de Fora. Among its approximately 70 species that comprise the floristic heritage of Selvagens, we found 8 taxa endemic to that sub-archipelago: some cases for example, Scilla maderensis Mnzs var. melliodora Svent., Argyranthemum thalassophilum (Svent) Humphr, Lobuta@a maritime (L.) Desv. var. rosula - venti Svent., Lotus sal crisis Svent), Monanthes lowei (Paiva) Perez et Acebes and Euphorbia desfoliata Svent. The latter is a host for Deuchalion oceanicus, endemic to -Ilhéu de Fora.