An index of functional diversity

Abstract. Functional diversity has been seen as the key to predicting the stability, invasibility, resource capture, nutrient cycling and productivity of communities. However, it has been unclear how to estimate it. Ten criteria for an index of functional diversity are developed. These include that it should reflect the range of characters present and the abundance of the species with those characters in the community, and be unaffected by the measurement units used or by the number of species. An index that meets all ten criteria, FD_var, is investigated. It is based on the variance in characters, weighted by the abundance of the species with those characters. Tested with artificial and randomly generated data, it showed reasonable use of the 0 ‐ 1 range (mean 0.60, range 0.0009 ‐ 0.975) and intuitive behaviour. Tested with field data from eight sites in New Zealand, it gave a good spread of values (mean 0.65, range across sites 0.34 ‐ 0.84), showed good ability to distinguish between the communities and its performance was ecologically intuitive. Illustrative correlations are made with mean annual temperature and soil fertility, determined by a bio‐assay. FD_var is recommended for general use.     

NATURA 2000 – The influence of the European directives on the development of nature-based sport and outdoor recreation in mountain areas

In all member countries of the European Community, the influence of European directives is increasing. This is especially the case with directives on the conservation of natural habitats and wild fauna and flora (European Council Directive 92/43 EEC from 1992 (Council of the European Union 1992) and the directive on the conservation of wild birds (European Council directive 79/409 EEC from 1979 (Council of the European Union 1979). These directives are expected to influence the future development of nature-based sport and outdoor recreation significantly. Many German sport organisations are expecting negative consequences for the future development of nature-based sport in mountain areas. This paper summarises key findings of a study commissioned by the German Sport Association.

This project develops guidelines for the application and interpretation of these directives, as well as for their practicable use and management. The study shows that the potential negative effects of nature-based sport and outdoor recreation activities can be categorised into three general types. Furthermore, large sport events should be evaluated separately in the future. Finally, the crucial role of management plans is discussed, which are essential if NATURA 2000 areas are to be established successfully. The management plan assists in the selection of suitable measures, helps to resolve conflicts, and increases the level of acceptance and its transparency for the public. This paper will demonstrate that the consultation and participation of local people including members of sport and recreational organisations is essential to achieve the best result in the interest of nature conservation in general and conservation of endangered habitats or species specifically.     

Typology and ecology of Californian serpentine annual grasslands

Abstract. A first classification for serpentine annual grasslands distributed throughout northern and central California is proposed. This study has followed the Braun‐Blanquet phyto‐sociological system based on floristical, biogeographical and bioclimatic features of the sampled areas. Numerical analyses of classification and ordination were applied to the floristic relevés. Minimum Variance Clustering grouped relevés into basic classification units that allowed us to define low‐hierarchical syntaxonomical units (associations) and ‘communities’. A Principal Coordinate Analysis was used to extract those ecological parameters related to the axes that separate those classification units from the previous dendrogram. The results showed that differences in species composition was mainly due to a continentality gradient and the shady effect of an overstory vegetation. On the basis of both analyses we propose a first syntaxonomic scheme on ultramafic (mainly serpentine) annual plant communities of the biogeographical Californian Region that comprises four associations, two subassociations and some provisional communities.     

Patterns of plant species and community diversity at different organization levels in a forested riparian landscape

Abstract. Integrated synusial phytosociology combined with traditional measures of diversity is used to describe the structure of vascular vegetation diversity along the forested riparian landscape of the upper Oise valley (Belgium and France). The two dimensions (longitudinal and lateral) of the geomorphological complex are examined at four scales: synusia, phytocoenosis, tesela and catena. The results support the following hypotheses: (1) the environmental gradients observed, particularly the lateral ones, are very complex; (2) there is a clear lack of coupling between the tree, shrub and herb layers, which indicates a differential response to the underlying influence of environmental controls; (3) moderate flooding‐induced disturbance enhances herb species richness; (4) stressful environments support a low plant species diversity but a high synusial richness; (5) natural factors (substrate, climate, disturbance) are more important at the synusia and phytocoenose scales, but (6) anthropogenic disturbances, mainly through forest and river management, are more important at the landscape level. By considering plant communities as structural‐dynamic entities of ecosystems in a landscape context, integrated synusial phytosociology provides a basis for decomposing a complex system since the different hierarchical levels are both nested and thus strongly relational and process‐based.     

Intracellular delivery of VIP-grafted sterically stabilized phospholipid mixed nanomicelles in human breast cancer cells

The purpose of this study was to determine whether biocompatible and biodegradable vasoactive intestinal peptide-grafted sterically stabilized phospholipid mixed nanomicelles (VIP-SSMM; size, approximately 15 nm), a novel nanosized actively targeted drug delivery platform for breast cancer, accumulate in human MCF-7 breast cancer cells. Using hydrophobic CdSe/ZnS quantum dots (QD), we found that QD-loaded VIP-SSMM accumulated significantly faster and in greater quantity in MCF-7 cells than did QD-loaded SSMM alone (p<0.05). This process was mediated, in part, by VIP receptors because excess human VIP, but not PACAP(6-38) or galanin, significantly attenuated this response (p<0.05). Taken together, these data indicate that VIP-SSMM are actively targeted to human breast cancer cells through VIP receptors. We suggest that VIP-SSMM could be used as an actively targeted nanosized drug delivery platform for breast cancer cells over-expressing VIP receptors.     

An allosteric circuit in caspase-1

Structural studies of caspase-1 reveal that the dimeric thiol protease can exist in two states: in an on-state, when the active site is occupied, or in an off-state, when the active site is empty or when the enzyme is bound by a synthetic allosteric ligand at the dimer interface ∼ 15 Å from the active site. A network of 21 hydrogen bonds from nine side chains connecting the active and allosteric sites change partners when going between the on-state and the off-state. Alanine-scanning mutagenesis of these nine side chains shows that only two of them—Arg286 and Glu390, which form a salt bridge—have major effects, causing 100- to 200-fold reductions in catalytic efficiency (k_cat/K_m). Two neighbors, Ser332 and Ser339, have minor effects, causing 4- to 7-fold reductions. A more detailed mutational analysis reveals that the enzyme is especially sensitive to substitutions of the salt bridge: even a homologous R286K substitution causes a 150-fold reduction in k_cat/K_m. X-ray crystal structures of these variants suggest the importance of both the salt bridge interaction and the coordination of solvent water molecules near the allosteric binding pocket. Thus, only a small subset of side chains from the larger hydrogen bonding network is critical for activity. These form a contiguous set of interactions that run from one active site through the allosteric site at the dimer interface and onto the second active site. This subset constitutes a functional allosteric circuit or “hot wire” that promotes site-to-site coupling.     

Systematics Agenda 2000: an historical perspective

The publication of Systematics Agenda 2000 in February, 1994 represented an historic event in the collaboration of the systematic biology community designed to set a research agenda for a twenty five year period across the areas of basic and applied systematics. How the community came to take the initiative to produce such a consensus is outlined. Of special interest is the emergence of the Systematics Agenda 2000 initiative from a North American perspective to a truly global enterprise.     

Soil pH and phosphorus drive species composition and richness in semi-natural heathlands and grasslands unaffected by twentieth-century agricultural intensification

Background: Increased soil phosphorus (P) caused by agricultural intensification has been associated with decreased plant species richness (SR) in central Europe. How plant communities and soil P gradients are related in unimproved open habitats remains unclear.

Aims: The aim of this article was to characterise the relationship between soil chemical parameters and plant species composition and richness in unimproved open habitats.

Methods: The influence of soil chemical parameters (pH, P, K, Mg) on species composition was assessed, using data from 40 heathland and 54 grassland plots, by non-metric multidimensional scaling and permutational multivariate analysis of variance. The relationship between soil chemical parameters and SR was tested by linear mixed effects models.

Results: A direct relationship between heathland community composition and pH was observed, explaining 10% of variation in species composition, while P, Mg and pH together explained 17% of variation in grassland composition. In heathlands, SR increased with increasing pH, whereas in grasslands, SR decreased with increasing soil P.

Conclusions: Soil chemical parameters were substantially related to plant community composition and richness. In an area spared from a century of agricultural intensification, reduced pH appeared to constrain SR in heathlands, while even slight P increases (<10 mg kg^?1) depressed plant SR in semi-natural grasslands.