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The prevention of biodiversity loss in agricultural landscapes to protect ecosystem stability and functions is of major importance to stabilize overall diversity. Intense agriculture leads to a loss in species richness and homogenization of species pools, but the processes behind are poorly understood due to a lack of systematic case studies: The specific impacts by agriculture in contrast to other land-use creating open habitat are not studied as such landscapes hardly exist in temperate regions. Applying systematic grids, we compared the plant species distribution at the landscape scale between an active military training areas in Europe and an adjacent rather intensively used agricultural landscape. As the study areas differ mainly in the type of disturbance regime (agricultural vs. non-agricultural), differences in species pattern can be traced back more or less directly to the management. Species trait analyses and multiple measures of beta diversity were applied to differentiate between species similarities between plots, distance-decay, or nestedness. Contrary to our expectation, overall beta diversity in the agricultural area was not reduced but increased under agricultural. This was probably the result of species nestedness due to fragmentation. The natural process of increasing dissimilarity with distance (distance-decay) was suppressed by intense agricultural land-use, generalist and long-distance dispersers gained importance, while rare species lost continuity. There are two independent processes that need to be addressed separately to halt biodiversity loss in agricultural land. There is a need to conserve semi-natural open habitat patches of diverse size to favor poor dispersers and specialist species. At the same time, we stress the importance of mediating biotic homogenization caused by the decrease of distance-decay: The spread of long-distance dispersers in agricultural fields may be acceptable, however, optimized fertilizer input and erosion control are needed to stop the homogenization of environmental gradients due to nitrogen input into semi-natural habitat. [ABSTRACT FROM AUTHOR]

Lowland meadow irrigation used to be widespread in Central Europe, but has largely been abandoned during the 20th century. As a result of agri-environment schemes and nature conservation efforts, meadow irrigation is now being re-established in some European regions. In the absence of natural flood events, irrigation is expected to favour fauna typical of lowland wet meadows. We analysed the effects of traditional flood irrigation on diversity, densities and species composition of three invertebrate indicator taxa in lowland meadows in Germany. Unexpectedly, alpha diversity (species richness and Simpson diversity) and beta diversity (multivariate homogeneity of group dispersions) of orthopterans, carabids, and spiders were not significantly different between irrigated and non-irrigated meadows. However, spider densities were significantly higher in irrigated meadows. Furthermore, irrigation and elevated humidity affected species composition and shifted assemblages towards moisture-dependent species. The number of species of conservation concern, however, did not differ between irrigated and non-irrigated meadows. More variable and intensive (higher duration and/or frequency) flooding regimes might provide stronger conservation benefits, additional species and enhance habitat heterogeneity on a landscape scale. [ABSTRACT FROM AUTHOR]

We address the challenging problem of algorithm and program design for the Computational Grid by providing the application user with a set of high-level, parameterized components called skeletons. We describe a Java-based Grid programming system in which algorithms are composed of skeletons and the computational resources for executing individual skeletons are chosen using performance prediction. The advantage of our approach is that skeletons are reusable for different applications and that skeletons' implementations can be tuned to particular machines. The focus of this paper is on predicting performance for Grid applications constructed using skeletons. [ABSTRACT FROM AUTHOR]

Aims: Lowland meadow irrigation used to be a widespread management practice to improve hay yield in Central European grasslands. Recently, traditional meadow irrigation is being re-established in some parts of Europe. Nevertheless, the consequences of the regular artificial flooding on vegetation of these water meadows remain poorly understood. We studied the impact of flood irrigation on the plant functional and species composition of extensively managed hay meadows. Location: Lowland of River Queich, between Landau and Lustadt, Germany. Methods: We sampled vegetation in 34 meadows that differed in irrigation status (irrigated/non-irrigated) and fertilization (unfertilized/fertilized). Plants were classified into functional groups according to growth forms, N-fixing ability and reproductive strategy. Effects of meadow irrigation on the plant functional composition were analysed using two complementary approaches. In the 'community approach', we analysed total cover of each functional group per meadow with respect to irrigation and fertilization. In the 'species approach', we analysed the mean response to irrigation among the species within the defined functional groups. Results: Total cover of rosettes and semi-rosettes increased relative to graminoids in irrigatedmeadows. Cover of legumes was three times higher in irrigated compared to non-irrigated meadows. Irrigation enhanced preferences for seed and vegetative reproduction. However, the response of individual species within the functional groups was inconsistent. Fertilization had an overall minor influence on functional composition of the meadows. Conclusions: The higher proportion of plants with basal growth organs in irrigated meadows suggests that irrigation may enhance a more complex vertical structure of the vegetation. Enhancement of rosettes, semi-rosettes and legumes at the cost of graminoids through irrigation was more significant in the community than in the species approach, indicating that the functional group response was amplified by the respective dominant species. This highlights the importance of considering species-level interactions in functional vegetation analysis. [ABSTRACT FROM AUTHOR]

Abstract: We consider the development of software systems that integrate collaborative real-time modeling and distributed computing. Our main goal is user-orientation: we need a collaborative workspace for geographically dispersed users with a seamless access of every user to high-performance servers. This paper presents a particular prototype, Clayworks, that allows modeling of virtual clay objects and running computation-intensive deformation simulations for objects crashing into each other. In order to integrate heterogeneous computational resources, we adopt modern Grid middleware and provide the users with an intuitive graphical interface. Simulations are parallelized using a higher-order component (HOC) which abstracts over the web service resource framework (WSRF) used to interconnect our worksuite to the computation server. Clayworks is a representative of a large class of demanding systems which combine collaborative, user-oriented modeling with performance-critical computations, e.g., crash-tests or simulations of biological population evolution. [Copyright &y& Elsevier]