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Invasions! Guardiola, M., Gutiérrez, C., Pérez-Haase, A., Jover, M.
i Corbera, J. Les plantes al·lòctones del sector central de la
Serralada Litoral catalana (territori comprès entre el
riu Besòs i la Tordera) Alloctonous plants from the central section of the Catalan Littoral Range (the region between the Besós and the Tordera rivers) The flora of this region was exhaustively studied by Dr. Pere Montserrat between the years 1945 and 1950. Since then, the area has suffered a high increase in urban occupation compared to its former use as agricultural land, a fact that has favoured the introduction of a high number of allochthonous flora. In this article, a check-list of the existing allochthonous flora is presented and its current composition is compared with that observed in 1950. 176 taxa belonging to 54 families are listed, accounting for 13.6% of the total flora studied from this region. Compositae and Gramineae are the families containing higher numbers of taxa (36 and 23, respectively). Life forms of the allochthonous flora are dominated by therophytes (35.2%) and hemicryptophytes (21.0%), a trend mirrored in other regions of the Iberian Peninsula. Since 1950, the number of allochthonous taxa has increased in 75 species, with a mean rate of introduction of 1.29 species per year. Despite the high number of allochthonous species, only 15.9% of them may be classified as invasive. During the last 58 years, some species with agricultural affinities have disappeared, whereas the number of exotic species used in gardening has increased considerably. Regulation by local government is needed in order to better manage this growing problem. |
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