The Biodiversity of the Mediterranean Sea: Estimates, Patterns, and Threats

The Mediterranean Sea is a marine biodiversity hot spot. Here we combined an extensive literature analysis with expert opinions to update publicly available estimates of major taxa in this marine ecosystem and to revise and update several species lists. We also assessed overall spatial and temporal patterns of species diversity and identified major changes and threats. Our results listed approximately 17,000 marine species occurring in the Mediterranean Sea. However, our estimates of marine diversity are still incomplete as yet—undescribed species will be added in the future. Diversity for microbes is substantially underestimated, and the deep-sea areas and portions of the southern and eastern region are still poorly known. In addition, the invasion of alien species is a crucial factor that will continue to change the biodiversity of the Mediterranean, mainly in its eastern basin that can spread rapidly northwards and westwards due to the warming of the Mediterranean Sea. Spatial patterns showed a general decrease in biodiversity from northwestern to southeastern regions following a gradient of production, with some exceptions and caution due to gaps in our knowledge of the biota along the southern and eastern rims. Biodiversity was also generally higher in coastal areas and continental shelves, and decreases with depth. Temporal trends indicated that overexploitation and habitat loss have been the main human drivers of historical changes in biodiversity. At present, habitat loss and degradation, followed by fishing impacts, pollution, climate change, eutrophication, and the establishment of alien species are the most important threats and affect the greatest number of taxonomic groups. All these impacts are expected to grow in importance in the future, especially climate change and habitat degradation. The spatial identification of hot spots highlighted the ecological importance of most of the western Mediterranean shelves (and in particular, the Strait of Gibraltar and the adjacent Alboran Sea), western African coast, the Adriatic, and the Aegean Sea, which show high concentrations of endangered, threatened, or vulnerable species. The Levantine Basin, severely impacted by the invasion of species, is endangered as well

Dependencia y desarrollo: Sicilia e Italia del sur (s. XI-XVIII)

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Urbanizacion y finanzas de una ciudad portuaria: Palma de Mallorca en la Edad Media (siglos XIII-XV), pp. 159-183

[spa] Resumen: En el artículo se estudia el choque entre los proyectos reformistas del municipio, en una ciudad de clara vocación comercial, y los intereses de la Corona, que era la propietaria del suelo. Los proyectos municipales de reordenar la ribera del mar, obstaculizadas por numerosas construcciones autorizadas por la monarquía y de dotarse de una atarazana municipal chocaron con la negativa real. A pesar de que en 1273 Jaime I había donado la ribera al municipio, Pedro el Ceremonioso se opuso a desalojar a los toneleros y otros oficios establecidos en la zona, que obstaculizaban las operaciones de carga y descarga de mercancías. Pese a que el municipio había propuesto construir, en 1348, a sus expensas, una gran atarazana en un solar de propiedad real, la monarquía descartó la cesión de terreno para ello. La conflictividad mediterránea, a partir de mediados del siglo XIV, otorgó una prioridad a los gastos de guerra y por consiguiente fueron descartadas las inversiones en infraestructuras