Impacts of temperature and acidification on larval calcium incorporation of the spider crab <Emphasis Type="Italic">Hyas araneus</Emphasis> from different latitudes (54° vs. 79°N)

The combined effects of ocean warming and acidification were compared in larvae from two populations of the cold-eurythermal spider crab Hyas araneus, from one of its southernmost populations (around Helgoland, southern North Sea, 54°N, habitat temperature 3–18°C; collection: January 2008, hatch: January–February 2008) and from one of its northernmost populations (Svalbard, North Atlantic, 79°N, habitat temperature 0–6°C; collection: July 2008, hatch: February–April 2009). Larvae were exposed to temperatures of 3, 9 and 15°C combined with present-day normocapnic (380 ppm CO₂) and projected future CO₂ concentrations (710 and 3,000 ppm CO₂). Calcium content of whole larvae was measured in freshly hatched Zoea I and after 3, 7 and 14 days during the Megalopa stage. Significant differences between Helgoland and Svalbard Megalopae were observed at all investigated temperatures and CO₂ conditions. Under 380 ppm CO₂, the calcium content increased with rising temperature and age of the larvae. At 3 and 9°C, Helgoland Megalopae accumulated more calcium than Svalbard Megalopae. Elevated CO₂ levels, especially 3,000 ppm, caused a reduction in larval calcium contents at 3 and 9°C in both populations. This effect set in early, at 710 ppm CO₂ only in Svalbard Megalopae at 9°C. Furthermore, at 3 and 9°C Megalopae from Helgoland replenished their calcium content to normocapnic levels and more rapidly than Svalbard Megalopae. However, Svalbard Megalopae displayed higher calcium contents under 3,000 ppm CO₂ at 15°C. The findings of a lower capacity for calcium incorporation in crab larvae living at the cold end of their distribution range suggests that they might be more sensitive to ocean acidification than those in temperate regions.     

Lactation patterns of pinnipeds are not explained by optimization of maternal energy delivery rates

Within pinnipeds, phocids and otariids show differing maternal care strategies. Phocids rear young out of body stores in a yearly cycle with a single stay ashore when the mother fasts while lactating, whereas otariids provision their young by repeated foraging trips to sea alternating with brief stays ashore where they suckle their young. In a previous optimality model, these differences have been interpreted as adaptations based on differing energy requirements of large (phocid) and smaller (otariid) species, and the time budget of the large elephant and the much smaller Antarctic fur seal were correctly predicted. Our refined model—extended to pinniped species of all sizes—predicts lactation strategies to shift from attendance cycles to 1-year cycles with increasing body mass and provides an explanation for the finding that phocid pups are weaned at lower relative mass than otariid pups. However, other predictions do not correspond to empirical findings. In particular, the model does not explain the behavior of large otariids and small phocids. Thus, maternal metabolic requirements alone appear insufficient to explain observed lactation patterns. In the light of our results, we discuss more generally the scope and limitations of optimality models when applied in a comparative framework to a group of related species.     

“Arabidobrassica”: Plant-genome engineering by protoplast fusion

After fusion of somatic cells (isolated protoplasts) of Arabidopsis thaliana and Brassica campestris, plants could be regenerated in which genetic material from parents of taxonomically different tribes is combined. Between these regenerants asymmetric hybrids have also been obtained, in which one parental genome is represented by reduced chromosome numbers. Results concerning the analysis and genesis of these plants are used to discuss the question whether such monster plants are of any importance.     

Indicators of deforestation in the Southern Brazilian Pre-Amazon

In recent years, Amazonian deforestation has become a question of global concern. Deforestation in Amazon is a complex phenomenon in nature and has been related to traditional agriculture expansion. In this work, land use, socioeconomic and conservation indicators, combined with statistical analysis, were used to understand forces associated with patterns of deforestation. This approach was applied in Southern Brazilian Pre-Amazon in Mato Grosso State, which represents an extensive rain forest-savanna ecotone, located in the south border of Amazon biome. Based on data from the last two agricultural censuses (1995/1996–2006), we compared agricultural expansion in this area and Mato Grosso state. Results have shown that 85 % of state deforestation was concentrated in Southern Pre-Amazon and was closely related to increase in number of cattle and pasture area. PCA results pointed that population (92 %), number of cattle (86.5 %), pastures (84.2 %) and tractors (78.4 %) were variables with highest positive correlation to deforestation. It showed that GDP contributes to an individual axis and has a low correlation to deforestation (37.8 %). Conservation units and indigenous reserves also contribute to a single axis and were negatively correlated to temporary crops area. Results revealed a significant reduction in production and commercialization of extractive products in the region, revealing that the main, almost only conservation policy in Mato Grosso remains the creation of Special Areas. We suggest that further studies are necessary to screen development alternatives to simple cutting trees down. It is important to diversify strategies for deforestation control, and development aspects must be more seriously considered to reach a sustainable deforestation control policy.     

The nature of the migration route shapes physiological traits and aerodynamic properties in a migratory songbird

Migration distance is supposed to represent an important selection pressure shaping physiological and morphological properties. Previous work has focussed on this effect, while the importance of ecological barriers in this context has been rarely considered. We studied two subspecies of a migratory songbird, the northern wheatear (Oenanthe oenanthe oenanthe and O. o. leucorhoa L.), on an island in the North Sea. The former subspecies reaches their Scandinavian breeding areas after a short sea crossing, whereas leucorhoa northern wheatears cross the North Atlantic towards Iceland, Greenland or Canada. Physiological traits (fuel deposition rate) and wings’ aerodynamic properties (wing pointedness independent of body size), both affecting migration speed, were hypothesized to be more pronounced in leucorhoa than in oenanthe northern wheatears. Within subspecies, the physiological and aerodynamic properties were hypothesized to explain arrival date at the stopover site with “fast migrants” arriving early. Physiological and aerodynamic properties in leucorhoa northern wheatears lead to a faster and less costly migration, favouring a sea crossing, but in trade-off lower flight manoeuvrability than in oenanthe birds. Wings’ aerodynamic properties affected the seasonal occurrence of leucorhoa females, whereas the physiological traits significantly influenced arrival date in oenanthe individuals. The less risky migration route in oenanthe birds with few short sea crossings may have favoured higher flight manoeuvrability for foraging (less pointed wings), in trade-off an energetically more costly flight. Hence, not the migration distance itself, but the presence/absence of a sea barrier presents an important selection pressure in migratory land birds favouring low flight costs.