Ecological and biogeographical basis of avian rarity in Madrid (Central Spain)

Abstract

The conservation status of bird species of Comunidad de Madrid is analysed using the ecological breadth of the species, the distribution area, their habitat preferences, and maximum ecological densities in the region. The species which are less widely distributed in Madrid are characterized by their low maximum ecological densities, narrow habitat breadths, and limited distribution in the Iberian peninsular. Another component defining regional rarity shows that large-sized species tend to reach lower densities than small-sized birds. These two gradients of ecological rarity are closely associated with the current categories of threat status in Madrid, and allow the proposal and justification of possible modifications of the regional catalogue for 11 species.