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Although extinctions due to climate change are still uncommon, they might surpass those caused by habitat loss or overexploitation over the next few decades. Among marine megafauna, mammals fulfill key and irreplaceable ecological roles in the ocean, and the collapse of their populations may therefore have irreversible consequences for ecosystem functioning and services. Using a trait-based approach, we assessed the vulnerability of all marine mammals to global warming under high and low greenhouse gas emission scenarios for the middle and the end of the 21 st century. We showed that the North Pacific ocean, the Greenland Sea and the Barents Sea host the species that are most vulnerable to global warming. future conservation plans should therefore focus on these regions, where there are long histories of overexploitation and there are high levels of current threats to marine mammals. Among the most vulnerable marine mammals were several threatened species, such as the North Pacific right whale (Eubalaena japonica) and the dugong (Dugong dugon), that displayed unique combinations of functional traits. Beyond species loss, we showed that the potential extinctions of the marine mammals that were most vulnerable to global warming might induce a disproportionate loss of functional diversity, which may have profound impacts on the future functioning of marine ecosystems worldwide. During the past few decades, the Earth has entered a new era of rapid and potentially irreversible climate warming due to the positive radiative imbalances triggered by greenhouse gas emissions from human activities 1,2. The oceans have taken up 93% of the extra energy 1 that has been accumulated in the Earth system in recent decades, and its temperature has increased much faster since 1991 than has been recorded previously 2. In addition, changes in ocean temperature also affect the sea level, sea ice extent and salinity (through changes in precipitation and evaporation). All these changes were found to have negative impacts on marine biota 3,4 and especially on marine mammals (e.g. 5-10). One of the most common responses of marine mammals to temperature changes is shifts in their spatial distributions, which could result in modifications of the ranges of the species (e.g. 11-13). For example, Bryde's whales (Balaenoptera brydei), a widely spread subtropical and tropical species, was increasingly detected in the cooler waters off southern California during the period from 2000-2010 14. In contrast, the white-beaked dolphin (Lagenorhynchus albirostris), a cold-water species, has reduced its range and is declining in abundance 12. As mentioned by Elliott & Simmonds 12 , geography could constrain species with low dispersal ability to a particular area. For example, the distribution of an endemic species of porpoise, the vaquita (Phocoena sinus), is limited to the northern end of the Gulf of California. Changes in water temperatures could alter the life cycles of the prey of marine mammal and provoke mismatches between the abundance of prey and ...

ABSTRACT1. The non-indigenous species Corbicula fluminea (Mu¨ller, 1774) is one of the most invasive bivalves in freshwater ecosystems. This Asian clam was first reported in the River Minho estuary in 1989. After a short period of time, it became the major component of the local benthic fauna in terms of abundance and biomass.2. In the autumn of 2004 and 2005, spatial and temporal variations in abundance, biomass and population structure of C. fluminea were investigated at 16 sites in the freshwater subtidal area of the River Minho estuary. Mean abundance and biomass per site ranged from 80 to 4185 ind. m À2 and 8.5 to 465.9 g AFDW m À2 , respectively. 3. The environmental characterization of the area was performed through multivariate analysis, which revealed three distinct areas subjected to different abiotic conditions. C. fluminea population structure is well correlated with these three distinct areas.4. The combination of several abiotic variables determining C. fluminea biomass distribution was evaluated through a stepwise multiple regression. This model showed that redox potential, nutrient concentrations, hardness, organic matter and sediment characteristics explained almost 60% of the variation in C. fluminea biomass in the freshwater subtidal area of the River Minho estuary (R 2 ¼ 59:3%; F ½9;86 ¼ 13:9; p50.001). 5. Improved ecological knowledge is essential for future C. fluminea management, in order to protect local habitats and biodiversity, and to reduce the economic impact of this non-indigenous invasive species.

Climatic variability of Marine Isotope Stage (MIS) 11 is examined using a new high-resolution direct land—sea comparison from the SW Iberian margin Site U1385. This study, based on pollen and biomarker analyses, documents regional vegetation, terrestrial climate and sea surface temperature (SST) variability. Suborbital climate variability is revealed by a series of forest decline events suggesting repeated cooling and drying episodes in SW Iberia throughout MIS 11. Only the most severe events on land are coeval with SST decreases, under larger ice volume conditions. Our study shows that the diverse expression (magnitude, character and duration) of the millennial-scale cooling events in SW Europe relies on atmospheric and oceanic processes whose predominant role likely depends on baseline climate states. Repeated atmospheric shifts recalling the positive North Atlantic Oscillation mode, inducing dryness in SW Iberia without systematical SST changes, would prevail during low ice volume conditions. In contrast, disruption of the Atlantic meridional overturning circulation (AMOC), related to iceberg discharges, colder SST and increased hydrological regime, would be responsible for the coldest and driest episodes of prolonged duration in SW Europe.

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Liocarcinus depurator is the most abundant brachyuran by--catch from commercial trawl fisheries along the Spanish Mediterranean coast. Individuals of this species were collected from bottom trawl surveys covering the entire Iberian Mediterranean coast (from Gibraltar to Cape Creus), throughout the species' depth distribution. Geometric morphometric techniques were used to determine any differences in shape between male and female crabs. Differences in shape not observed with traditional morphometric techniques were detected. Females were found to have a larger base of the abdomen which is discussed in the context of reproductive success.

The commercially fished striped venus clams Chamelea gallina and C. striatula (Bivalvia: Veneridae) are difficult to distinguish by inexperienced observers and the taxonomy of these species is still an issue of discussion. The differences in shape between C. gallina and C. striatula from Portuguese coastal waters were studied through conventional linear and geometric morphometric analysis, using both contour (elliptic Fourier analysis) and landmark-based methods. The relationships shell length vs. height, width, and total weight were significantly different between species. However, because there was a considerable overlap in the data sets, the species could not be distinguished using any combination of those linear measurements. Geometric morphometric methods provided shape variables that led to 0-6% misclassification rates between species; linear morphometric measures led to 16.8% error. Contour analysis revealed differences primarily in the shell umbo and lunular area. The umbo was more "sharp" and the lunula less pronounced in C. striatula than in C. gallina. Generalized procrustes superimposition (landmark analysis) showed that the main differences between species reside in the length of the pallial sinus. Thus, an index was developed (PI: Pallial Index = pallial sinus length/shell length), which was successfully used to separate the species (with 100% correct classification), i.e., specimens with PI lower than 0.119 belonged to C. gallina, whereas greater PI values were attributed to C. striatula. The use of these geometric morphometric methods allowed the detection of differences in shape between these two species and to develop an easy-to-use identification index. We encourage the development of analogous indices that apply the methods of geometric morphometrics to distinguish between other species whose identification is complicated.