Resumen de Diversidad y conservación de las comunidades vegetales del Estrecho de Gibraltar
Fernando Ojeda Copete, Juan Arroyo Marín, Teodoro Marañón Arana
The region of the Strait of Gibraltar presents geological, climatological, biogeographical and ecological characteristics that are uncommon in the Mediterranean Basin. Al1 this, combined with a certain level of conservation in some zones, has determined its high plant species richness. Landuse characteristics differ greatly on both shores shores of the Straits. The actual state of conservation is also very different as there is a greater level of disturbance and less plant species diversity of the African side. In recent years there have been studies on a large number of samples ofplant communities on both sides oj the Straits. Shrub and tree cover, species diversity, taxonomic and biogeographical status, soil nutrients and nutrient levels in plants have been studied. Al1 these data1 together with other studies in progress, seen to be establishing clear pattems of diversity and endemism. Tne most diverse communities are those found in areas with intermediate levels of soilfertilityl althoufi the proportion of endemics isgreater in Izeather-dominated communities where the soil is most acid andpoorest. In general, the Moroccan communities tend to have less diversity, possibly partly due to the greater impact of overgrazing and partly due to the fragmented character of areas with acid soils. Similarly the pattern of divers$cation of the most important taxonomic groups seems associated with the strong selective pressures provided by the abundance ofpooracid soils. Observed trends allow proposals to be mude regarding which forms of land use will favour the conservation of the notable botanical heritage of the region.
