Natura Pitiusa

The Mediterranean Sea, one of the regions warming fastest nder climate change1,2, harbours lush seagrass (Posidoniaoceanica) meadows that form the basis for a key ecosystem inthe region. Recent field results have shown that increases maximum annual seawater temperature in the Mediterranean has already led to increased seagrass mortality . Here we project the trajectory of P. oceanica meadows under the warming expected in the western Mediterranean through the twenty-first century to conclude that warming will lead to the functional extinction of P. oceanica meadows by the middle of this century (year 2049 ± 10) even under a relatively mild greenhouse-gas emissions scenario. Efforts to alleviate local stresses adding to the loss of P. oceanica meadows will have a limited effect in conserving the meadows under climate change. Efforts to mitigate climate change are urgently needed to preserve this key ecosystem Jordà, G. et al (2012). Nature Climate Change DOI: 10.1038/NClimate 1533

The protection of organic carbon stored in forests is considered as an important method for mitigating climate change. Like terrestrial ecosystems, coastal ecosystems store large amounts of carbon, and there are initiatives to protect these ‘blue carbon’ stores. Organic carbon stocks in tidal salt marshes and mangroves have been estimated, but uncertainties in the stores of seagrass meadows—some of the most productive ecosystems on Earth—hinder the application of marine carbon conservation schemes. Here, we compile published and unpublished measurements of the organic carbon content of living seagrass biomass and underlying soils in 946 distinct seagrass meadows across the globe. Using only data from sites for which full inventories exist, we estimate that, globally, seagrass ecosystems could store as much as 19.9 Pg organic carbon; according to a more conservative approach, in which we incorporate more data from surface soils and depth-dependent declines in soil carbon stocks, we est

The decline of important coastal habitats, like seagrass meadows, is likely to influence populations of associated species, like the noble pen shell, Pinna nobilis. Here we used a Bayesian formulation of individual covariate models to derive a reliable estimate of populations of P. nobilis in shallow, and thus usually most impacted, areas around the island of Majorca, Balearic Islands, Spain. At six evaluated sites we find quite distinct densities ranging from 1.4 to 10.0 individuals/100 m2. These differences in density could not be explained by habitat factors like shoot density and meadow cover, nor did dislodgement by storms (evaluated by maximum wind speeds at the sites) seem to play an important role. However, noble pen shell density was related to anchoring as at sites where anchoring was not permitted the average density was 7.9 individuals/100 m2 while in sites where ships anchored the density was on average 1.7 individuals/100m2. As for the conservation of Posidonia oceanica

RESUMEN Los mosquiteros musicales europeos atraviesan las costas mediterráneas españolas en migración postnupcial durante los meses de agosto. septiembre y octubre. En promedio pasan con anterioridad los individuos originarios de zonas más septentrionales y sucesivamente los pertenecientes a poblaciones más medionales. La cola del paso migratorio esta constituida por un muy alto porcentaje de jóvenes. superior al del resto de la migración. La actividad diurna es máxima en tomo a las dos-cuatro horas después del orto y mucho más débil a lo largo del día hasta comenzar de nuevo. cada noche. la migración a parlir del ocaso. No parecen presentar periodos de descanso de más de un día, a lo largo del cual no se detectan incrementos de peso. aunque esto puede deber a la falta de mayor precisión en las medidas. Mientras atraviesan el continente europeo la acumulación grasa es sólo la neasaria para realizar sus cortas jornadas de vuelo. evitando asi una sobrecarga. Sin embargo, a lo largo de