La presencia de especies exóticas en el Norte de Portugal y los corredores florísticos: un enfoque biogeográfico

Abstract

The occurrence and geographical distribution of fifty nine alien taxa are shown for the North of Portugal. New references (Panicum dichotomiflorum, Penisetum villosum, Hakea sericea, and Montia perfoliata) are included in this chorological upgrade of the non-indigenous flora identified. The geographical distribution of those taxa was correlated with the temperature, precipitation and altitudinal information coming from the fifteen thermopluviometric stations from the North of Portugal, and with the biogeographic map of Costa et al. (1998). The multivariate statistical analysis involved showed apparent corridors of floristic dynamic for this alien species, along this area. The description of the altitudinal and thermopluviometric variation showed the importance of the Douro river in defining the complexity of the Atlantic-Mediterranean biogeographic transition in the North of Portugal. This floristic corridor allows an important access of this eminently thermophilous flora. This new approach shows the Atlantic influence extended by the lowlands of the eastern side, and the occidental chain mountain Gerês-Larouco-Alvão-Marão-Montemuro-Lapa as a diffe­rent biogeographical area.