Chilling-Induced Photoinhibition in Two Oak Species: Are Evergreen Leaves Inherently Better Protected Than Deciduous Leaves?

We compared the sensitivity to cold stress, in terms of photosynthetic capacity and changes in chlorophyll fluorescence of photosystem 2 (PS2), of an evergreen and a deciduous oak species, which co-occur in the southeastern United States. We predicted that the evergreen species, Quercus virginiana, which must endure winter, is likely to have an inherently greater capacity for energy dissipation and to be less susceptible to chilling stress than the deciduous species, Quercus michauxii. Short-term cold stress in both species lead to greater than 50 % reduction in maximum photosynthetic rates, 60-70 % reduction in electron transport, and irreversible quenching of PS2 fluorescence. The kinetics of recovery in the dark after exposure to 1 h high irradiance (1000 μmol m^-2 s^-1) and chilling (5 °C) showed that the evergreen Q. virginiana exhibited more protective q_E and less irreversible quenching (q_I) than the deciduous Q. michauxii. The large q_E which we observed in Q. virginiana suggests that the capacity for photoprotection at low temperatures is not induced by a long-term acclimation to cold but preexists in evergreen leaves. This capacity may contribute to the ability of this species to maintain leaves during the winter. This revised version was published online in June 2006 with corrections to the Cover Date.     

Are Echinocandins Better Than Azoles for Invasive Candidiasis?

Antifungal therapy has advanced tremendously in the past decade, with multiple new agents for systemic fungal infections that have a broad spectrum of activity and are well-tolerated. There is usually more than one acceptable therapeutic option for many diseases, and this is true in particular of candidiasis. Fluconazole has been the drug of choice for most clinical syndromes of candidiasis, due to its tolerability, effectiveness, and ease of administration. However, the echinocandin class of antifungals, comprised of caspofungin, micafungin and anidulafingin, has emerged as the preferred choice in the therapy of invasive candidiasis and candidemia. Their potent fungicidal activity and minimal toxicity have made them first-line drugs for this indication. In certain clinical settings, they may even be agents of first choice. Nevertheless, recent trends in echinocandin resistance demonstrated with Candida glabrata mandate ongoing surveillance, and continued trends may impact upon future antifungal selection.     

Unusual Fine Root Distributions of Two Deciduous Tree Species in Southern France: What Consequences for Modelling of Tree Root Dynamics?

The spatial distribution of fine roots of two deciduous tree species was investigated in contrasting growing conditions in southern France. Hybrid walnut trees (Juglans regia×nigra cv. NG23) and hybrid poplars (Populus euramericana cv. I214) were both cultivated with or without annual winter intercrops for 10 years on deep alluvial soils. Soil samples for measuring the fine root distribution of both trees and crops were obtained by soil coring down to 3-m depth at several distances and orientations from the tree trunk. The distribution of live fine roots from walnut and poplar trees was patchy and sometimes unexpected. In the tree-only stands, fine root profiles followed the expected pattern, as fine root density decreased with increasing depth and distance from the tree trunk. However, many fine root profiles under intercropped trees were uniform with depth, and some inverse profiles were observed. These distributions may result from a high degree of plasticity of tree root systems to sense and adapt to fluctuating and heterogeneous soil conditions. The distortion of the tree root system was more pronounced for the walnut trees that only partially explored the soil volume: in the tree-only stand, the walnut rooting pattern was very superficial, but in the intercropped stand walnut trees developed a deep and dense fine root network below the crop rooting zone. The larger poplars explored the whole available soil volume, but the intercrop significantly displaced the root density from the topsoil to layers below 1 m depth. Most tree root growth models assume a decreasing fine root density with depth and distance from the tree stem. These models would not predict correctly tree–tree and tree–understorey competition for water and nutrients in 3D heterogeneous soil conditions that prevail under low-density tree stands. To account for the integrated response of tree root systems to such transient gradients in soils, we need a dynamic model that would allow for both genotypic plasticity and transient environmental local soil conditions.     

Epiphytic Refugium: Are Two Species of Invading Freshwater Bivalves Partitioning Spatial Resources?

Enumeration of benthic (bottom dwelling) and epiphytic (attached to plants) zebra and quagga mussels (Dreissena polymorpha and D. bugensis, respectively) at Lake Erie near-shore sites in fall of 2000 revealed an unexpected prevalence of the zebra mussel on submerged plants. Even at Buffalo, New York, USA, where benthic dreissenids have been 92–100% quagga mussel since 1996, zebra mussels constituted 30–61% of epiphytes numerically. This may reflect a partitioning of settling space consistent with interspecific competition. A seasonal epiphytic refugium might allow the zebra mussel to persist even where the benthos is almost exclusively quagga mussel. This revised version was published online in July 2006 with corrections to the Cover Date.     

Are Protected Areas Required to Maintain Functional Diversity in Human-Modified Landscapes?

The conversion of forest to agriculture across the world’s tropics, and the limited space for protected areas, has increased the need to identify effective conservation strategies in human-modified landscapes. Isolated trees are believed to conserve elements of ecological structure, providing micro-sites for conservation in matrix landscapes, and facilitating seed dispersal and forest restoration. Here we investigate the role of isolated Ficus trees, which are of critical importance to tropical forest ecosystems, in conserving frugivore composition and function in a human-modified landscape in Assam, India. We surveyed the frugivorous birds feeding at 122 isolated Ficus trees, 33 fruit trees, and 31 other large trees across a range of 32 km from the nearest intact forest. We found that Ficus trees attracted richer and more abundant assemblages of frugivores than the other tree categories. However, incidence function estimates revealed that forest specialist species decreased dramatically within the first kilometre of the forest edge. Despite this, species richness and functional diversity remained consistent across the human-modified landscape, as habitat generalists replaced forest-dependent frugivores, and accounted for most of the ecological function found in Ficus trees near the forest edge. We recommend that isolated Ficus trees are awarded greater conservation status, and suggest that their conservation can support ecologically functional networks of frugivorous bird communities.     

Conservation Targets for Viable Species Assemblages in Canada: Are Percentage Targets Appropriate?

Percentage targets for conservation have become a popular tool (advocated in both the scientific literature and the conservation community) for setting minimum goals for the amount of land to be set aside as protected areas. However, there is little literature to support a consistent percentage target that might be widely applied. Moreover, most percentage targets have not taken into account issues of species persistence. A recent study of herbivores in Kruger National Park took into account issues of representation and persistence in setting conservation targets and found that results were consistently about 50% and were unaffected by different permutations of the reserve selection process. Here, we carry out a similar analysis for representation of mammals within sites that are predicted to allow for their persistence, across eight ecologically defined regions in Canada to test whether we see similar consistent patterns emerging. We found that percentage targets varied with the different permutations of the reserve selection algorithms, both within and between the study regions. Thus, we conclude that the use of percentage targets is not an appropriate conservation strategy.     

Sponge Mass Mortalities in a Warming Mediterranean Sea: Are Cyanobacteria-Harboring Species Worse Off?

Mass mortality events are increasing dramatically in all coastal marine environments. Determining the underlying causes of mass mortality events has proven difficult in the past because of the lack of prior quantitative data on populations and environmental variables. Four-year surveys of two shallow-water sponge species, Ircinia fasciculata and Sarcotragus spinosulum, were carried out in the western Mediterranean Sea. These surveys provided evidence of two severe sponge die-offs (total mortality ranging from 80 to 95% of specimens) occurring in the summers of 2008 and 2009. These events primarily affected I. fasciculata, which hosts both phototrophic and heterotrophic microsymbionts, while they did not affect S. spinosulum, which harbors only heterotrophic bacteria. We observed a significant positive correlation between the percentage of injured I. fasciculata specimens and exposure time to elevated temperature conditions in all populations, suggesting a key role of temperature in triggering mortality events. A comparative ultrastructural study of injured and healthy I. fasciculata specimens showed that cyanobacteria disappeared from injured specimens, which suggests that cyanobacterial decay could be involved in I. fasciculata mortality. A laboratory experiment confirmed that the cyanobacteria harbored by I. fasciculata displayed a significant reduction in photosynthetic efficiency in the highest temperature treatment. The sponge disease reported here led to a severe decrease in the abundance of the surveyed populations. It represents one of the most dramatic mass mortality events to date in the Mediterranean Sea.     

Are Species Coexistence Areas a Good Option for Conservation Management? Applications from Fine Scale Modelling in Two Steppe Birds

Biotic interactions and land uses have been proposed as factors that determine the distribution of the species at local scale. The presence of heterospecifics may modify the habitat selection pattern of the individuals and this may have important implications for the design of effective conservation strategies. However, conservation proposals are often focused on a single flagship or umbrella species taken as representative of an entire assemblage requirements. Our aim is to identify and evaluate the role of coexistence areas at local scale as conservation tools, by using distribution data of two endangered birds, the Little Bustard and the Great Bustard. Presence-only based suitability models for each species were built with MaxEnt using variables of substrate type and topography. Probability maps of habitat suitability for each species were combined to generate a map in which coexistence and exclusive use areas were delimitated. Probabilities of suitable habitat for each species inside coexistence and exclusive areas were compared. As expected, habitat requirements of Little and Great Bustards differed. Coexistence areas presented lower probabilities of habitat suitability than exclusive use ones. We conclude that differences in species'' habitat preferences can hinder the efficiency of protected areas with multi-species conservation purposes. Our results highlight the importance of taking into account the role of biotic interactions when designing conservation measurements.     

“Women Are Better Than Men”–Public Beliefs on Gender Differences and Other Aspects in Multitasking

Reports in public media suggest the existence of a stereotype that women are better at multitasking than men. The present online survey aimed at supporting this incidental observation by empirical data. For this, 488 participants from various ethnic backgrounds (US, UK, Germany, the Netherlands, Turkey, and others) filled out a self-developed online-questionnaire. Results showed that overall more than 50% of the participants believed in gender differences in multitasking abilities. Of those who believed in gender differences, a majority of 80% believed that women were better at multitasking. The main reasons for this were believed to be an evolutionary advantage and more multitasking practice in women, mainly due to managing children and household and/or family and job. Findings were consistent across the different countries, thus supporting the existence of a widespread gender stereotype that women are better at multitasking than men. Further questionnaire results provided information about the participants’ self-rated own multitasking abilities, and how they conceived multitasking activities such as childcare, phoning while driving, and office work.     

Are We Losing the Best Parts of Our Protected Areas in Tropical Mountains?

Protected areas (PAs) on tropical mountains undergo greater forest destruction in their lower altitudes. We compared the extent of forested, nonforested, and fragmented areas between lowland (<1000 m asl) and montane zones of the Blue Mountains inside the Blue and John Crow Mountains National Park established in Jamaica in 1993. We found that in 2008, inside the montane zone, only 4 percent of forest was cleared, and forest fragmentation was minimal. In the lowland zone, however, the percentage of forest cleared was seven times as high, and the density of fragments was 11-fold higher. We established twenty-five 0.04 ha lowland plots; ordination of tree species composition in these plots reflected a rainfall gradient, showing that plots on the wetter northern side of the Blue Mountains were floristically different from those on the drier southern side. The conservation value of the remaining lowland forest is high because of its high endemism (18% of species in our plots) and beta diversity. In addition, IUCN Red List data show that about 71 percent of threatened tree species in the Blue Mountains grow in the lowland region, 92 percent of which are endemic. From these findings, we identify a ‘protected area hotspot zone’, which lies between the PA boundary and the core high-altitude zone, and which should be instituted in IUCN categories I and II PAs.     

Habitat Association in Two Genetic Groups of the Insect-Pathogenic Fungus Metarhizium anisopliae: Uncovering Cryptic Species?

Strains of insect-pathogenic fungi with high virulence toward certain pest insects have great potential for commercial biological control applications. Identifying such strains has been a central theme in using fungi for biological control. This theme is supported by a persistent paradigm in insect pathology which suggests that the host insect is the predominant influence on the population genetics of insect-pathogenic fungi. In this study, a population genetics analysis of the insect-pathogenic fungus Metarhizium anisopliae from forested and agricultural habitats in Ontario, Canada, showed a nonrandom association of alleles between two distinct, reproductively isolated groups (index of multilocus association = 1.2). Analyses of the mitochondrial DNA showed no differences between the groups. The two groups were associated with different habitat types, and associations with insect hosts were not found. The group from forested areas showed an ability for cold-active growth (i.e., 8°C), while the group from the agricultural area showed an ability for growth at high temperatures (i.e., 37°C) and resilience to UV exposure. These results represent a significant paradigm shift; habitat selection, not host insect selection, drives the population structure of these insect-pathogenic deuteromycetous fungi. With each group we observed recombining population structures as well as clonally reproducing lineages. We discuss whether these groups may represent cryptic species. Worldwide, M. anisopliae may be an assembly of cryptic species, each adapted to certain environmental conditions. The association of fungal genotypes with habitat but not with host insects has implications on the criteria for utility of this, and perhaps other, fungal biocontrol agents.     

On the Occlusal Fit of Tribosphenic Molars: Are We Underestimating Species Diversity in the Mesozoic?

The complex occlusal fits between tribosphenic teeth are a rich source of information for taxonomic, phylogenetic, and evolutionary analysis. The degree of fit between upper and lower cheek teeth has been used to refer specimens to species-level taxa, but statistical data on occlusal fit in relation to taxonomic identity have been lacking. We used landmarks on upper and lower first molars of 20 bat populations representing 16 species to assess the degree of occlusal fit (1) between teeth from the same individual; (2) between teeth from different individuals belonging to the same populations; and (3) between teeth belonging to different populations. We found that the fit of teeth belonging to different populations was significantly worse than between those of the same population and that the degree of misfit increased linearly with time since common ancestry, albeit with substantial variance. We used our comparisons to assess the species-level diversity within Batodon, the smallest known placental mammal from the Cretaceous. Our data suggest, with caveats, that instead of belonging to a single species, the specimens assigned to Batodon represent at least two species as different as those belonging to different genera or families of living bats.     

Linking Self-Incompatibility,Dichogamy, and Flowering Synchrony in Two Euphorbia Species: Alternative Mechanisms for Avoiding Self-Fertilization?

Background

Plant species have several mechanisms to avoid selfing such as dichogamy or a self-incompatibility response. Dichogamy in a single flower may reduce autogamy but, to avoid geitonogamy, plants must show flowering synchronization among all their flowers (i.e. synchronous dichogamy). It is hypothesized that one species would not simultaneously show synchronous dichogamy and self-incompatibility because they are redundant mechanisms to reduce selfing; however, this has not been accurately assessed.

Methodology/Principal Findings

This expectation was tested over two years in two natural populations of the closely related Mediterranean spurges Euphorbia boetica and E. nicaeensis, which completely avoid autogamy by protogyny at the cyathia level. Both spurges showed a high population synchrony (Z<79), and their inflorescences flower synchronously. In E. nicaeensis, there was no overlap among the cyathia in anthesis of successive inflorescence levels and the overlap between sexual phases of cyathia of the same inflorescence level was uncommon (4–16%). In contrast, E. boetica showed a high overlap among consecutive inflorescence levels (74–93%) and between sexual phases of cyathia of the same inflorescence level (48–80%). The flowering pattern of both spurges was consistent in the two populations and over the two successive years. A hand-pollination experiment demonstrated that E. nicaeensis was strictly self-compatible whereas E. boetica was partially self-incompatible.

Conclusions/Significance

We propose that the complex pattern of synchronized protogyny in E. nicaeensis prevents geitonogamous crosses and, consequently, avoids selfing and inbreeding depression. In E. boetica, a high probability of geitonogamous crosses may occur but, alternatively, this plant escapes selfing through a self-incompatibility response. We posit that synchronous dichogamy and physiological self-incompatibility do not co-occur in the same species because each process is sufficiently effective in avoiding self-fertilization.     

How Many Species Are There? Public Understanding and Awareness of Biodiversity in Switzerland

This paper presents the results of interviews and a questionnaire study on public knowledge of the concept of biodiversity and of plant species richness in Switzerland. Despite its extensive use in science and policy making, the concept of biodiversity is not widely recognized or known to people in Switzerland. Overall, 60% of all study participants (161 grammar school pupils, 110 non-graduates, and 96 graduates in the Canton of Zurich) had never heard the term biodiversity, while the others had come across it primarily in the media. Few study participants considered their school education a relevant source of information about biodiversity. Study participants most frequently referred to the diversity of plants and animals when defining biodiversity, but also quite often believed that biodiversity had something to do with ecological concepts such as the equilibrium between all components of nature. Both young people and adults held widely inaccurate ideas of the plant species richness of communities. Particularly for Switzerland, plant species richness was strongly overestimated.