Rift Valley fever virus and European mosquitoes: vector competence of Culex pipiens and Stegomyia albopicta (= Aedes albopictus)

Rift Valley fever (RVF) is a mosquito‐borne disease caused by the Rift Valley fever virus (RVFV). Rift Valley fever affects a large number of species, including human, and has severe impact on public health and the economy, especially in African countries. The present study examined the vector competence of three different European mosquito species, Culex pipiens (Linnaeus, 1758) form molestus (Diptera: Culicidae), Culex pipiens hybrid form and Stegomyia albopicta (= Aedes albopictus) (Skuse, 1894) (Diptera: Culicidae). Mosquitoes were artificially fed with blood containing RVFV. Infection, disseminated infection and transmission efficiency were evaluated. This is the first study to assess the transmission efficiency of European mosquito species using a virulent RVFV strain. The virus disseminated in Cx. pipiens hybrid form and in S. albopicta. Moreover, infectious viral particles were isolated from saliva of both species, showing their RVFV transmission capacity. The presence of competent Cx. pipiens and S. albopicta in Spain indicates that an autochthonous outbreak of RVF may occur if the virus is introduced. These findings provide information that will help health authorities to set up efficient entomological surveillance and RVFV vector control programmes.     

Quantity versus quality: Endemism and protected areas in the temperate forest of South America

Abstract Identification of biodiversity hotspots is essential to conservation strategies aimed at minimizing the possibility of losing half of the world's species in the next 50 years. The aims of the present study were: (i) to locate and designate zones of endemism in the temperate forest of South America; and (ii) to compare the distribution of these areas with the distribution of existing protected areas in this habitat type. Endemism areas were determined by using parsimonious analysis of endemism, which identified zones of endemism on the basis of sets of endemic species that were restricted to two or more study areas. We used distribution information for five unrelated taxa (ferns, trees, reptiles, birds and mammals) to provide more reliable results and patterns than would work with only a single taxon or related taxa. The northern part of this region has high endemism for all of the taxa considered in this study. We demonstrate that although the temperate forest of South America has more than 30% of its area under some type of protection, correlation between protected areas and the areas of endemism is remarkably low. In fact, less than 10% of protected areas are situated in areas that have the greatest value for conservation (i.e. high endemism). Under the current strategy, biodiversity within South America's temperate forest is in danger despite the large amount of protected area for this forest type.     

Scaling ozone responses of forest trees to the ecosystem level in a changing climate

Many uncertainties remain regarding how climate change will alter the structure and function of forest ecosystems. At the Aspen FACE experiment in northern Wisconsin, we are attempting to understand how an aspen/birch/maple forest ecosystem responds to long-term exposure to elevated carbon dioxide (CO₂) and ozone (O₃), alone and in combination, from establishment onward. We examine how O₃ affects the flow of carbon through the ecosystem from the leaf level through to the roots and into the soil micro-organisms in present and future atmospheric CO₂ conditions. We provide evidence of adverse effects of O₃, with or without co-occurring elevated CO₂, that cascade through the entire ecosystem impacting complex trophic interactions and food webs on all three species in the study: trembling aspen (Populus tremuloides Michx.), paper birch (Betula papyrifera Marsh), and sugar maple (Acer saccharum Marsh). Interestingly, the negative effect of O₃ on the growth of sugar maple did not become evident until 3 years into the study. The negative effect of O₃ effect was most noticeable on paper birch trees growing under elevated CO₂. Our results demonstrate the importance of long-term studies to detect subtle effects of atmospheric change and of the need for studies of interacting stresses whose responses could not be predicted by studies of single factors. In biologically complex forest ecosystems, effects at one scale can be very different from those at another scale. For scaling purposes, then, linking process with canopy level models is essential if O₃ impacts are to be accurately predicted. Finally, we describe how outputs from our long-term multispecies Aspen FACE experiment are being used to develop simple, coupled models to estimate productivity gain/loss from changing O₃.     

Adoption behaviour by gulls: a new hypothesis

It appears that chicks are selected to run away and seek adoption in a foster-family when the level of investment they receive falls below a certain threshold. Predictions based on this hypothesis are in agreement with the available evidence in the literature.     

Spread and impact of introduced conifers in South America: Lessons from other southern hemisphere regions

The history of conifers introduced earlier elsewhere in the southern hemisphere suggests that recent invasions in Argentina, Brazil, Chile and Uruguay are likely to increase in number and size. In South Africa, New Zealand and Australia, early ornamental introductions and small forestry plantations did not lead to large‐scale invasions, while subsequent large plantations were followed with a lag of about 20–30 years by troublesome invasions. Large‐scale conifer plantation forestry in South America began about 50–80 years later than in South Africa, Australia and New Zealand, while reports of invasions in South America lagged behind those in the latter nations by a century. Impacts of invading non‐native conifers outside South America are varied and include replacement of grassland and shrubland by conifer forest, alteration of fire and hydrological regimes, modification of soil nutrients, and changes in aboveground and belowground biotic communities. Several of these effects have already been detected in various parts of South America undergoing conifer invasion. The sheer amount of area planted in conifers is already very large in Chile and growing rapidly in Argentina and Brazil. This mass of reproductive trees, in turn, produces an enormous propagule pressure that may accelerate ongoing invasions and spark new ones at an increasing rate. Regulations to control conifer invasions, including measures to mitigate spread, were belatedly implemented in New Zealand and South Africa, as well as in certain Australian states, inspired by observations on invasions in those nations. Regulations in South America are weaker and piecemeal, but the existing research base on conifer invasions elsewhere could be useful in fashioning effective regulations in South America. Pressure from foreign customers in South Africa has led most companies there to seek certification through the Forestry Stewardship Council; a similar programme operates in Australia. Such an approach may be promising in South America.     

The interpretation of leaf-drying curves

A theoretical expression for the rate of water loss through the surface of excised leaves has been derived so that curves fitted to experimental data can be used to infer physical properties of the leaves such as the solute concentration and the conductance for water vapour loss. The use of the equations is illustrated by reference to data from an experiment in which red spruce (Picea rubens Sarg.) and Norway spruce (P. abies(L.) Karst.) seedlings were grown under five different regimes: outdoors (±50% shade), in a greenhouse (±50% shade) and in controlled-environment chambers.