Recent climate change is recognized as a main cause of shifts in geographical distributions of species. The impacts of climate change may be aggravated by habitat fragmentation, causing regional or large scale extinctions. However, we propose that climate change also may diminish the effects of fragmentation by enhancing flight behaviour and dispersal of ectothermic species like butterflies. We show that under weather conditions associated with anticipated climate change, behavioural components of dispersal of butterflies are enhanced, and colonization frequencies increase. In a field study, we recorded flight behaviour and mobility of four butterfly species: two habitat generalists (Coenonympha pamphilus; Maniola jurtina) and two specialists (Melitaea athalia; Plebejus argus), under different weather conditions. Flying bout duration generally increased with temperature and decreased with cloudiness. Proportion of time spent flying 123Biodivers Conserv (2011) 20:483-503 DOI 10.1007 decreased with cloudiness. Net displacement generally increased with temperature. When butterflies fly longer, start flying more readily and fly over longer distances, we expect dispersal propensity to increase. Monitoring data showed that colonization frequencies moreover increased with temperature and radiation and decreased with cloudiness. Increased dispersal propensity at local scale might therefore lower the impact of habitat fragmentation on the distribution at a regional scale. Synergetic effects of climate change and habitat fragmentation on population dynamics and species distributions might therefore appear to be more complex than previously assumed.

Population viability analyses (PVAs) contribute to conservation theory, policy, and management. Most PVAs focus on single species within a given landscape and address a specific problem. This specificity often is reflected in the organization of published PVA descriptions. Many lack structure, making them difficult to understand, assess, repeat, or use for drawing generalizations across PVA studies. In an assessment comparing published PVAs and existing guidelines, we found that model selection was rarely justified; important parameters remained neglected or their implementation was described vaguely; limited details were given on parameter ranges, sensitivity analysis, and scenarios; and results were often reported too inconsistently to enable repeatability and comparability. Although many guidelines exist on how to design and implement reliable PVAs and standards exist for documenting and communicating ecological models in general, there is a lack of organized guidelines for designing, applying, and communicating PVAs that account for their diversity of structures and contents. To fill this gap, we integrated published guidelines and recommendations for PVA design and application, protocols for documenting ecological models in general and individual-based models in particular, and our collective experience in developing, applying, and reviewing PVAs. We devised a comprehensive protocol for the design, application, and communication of PVAs (DAC-PVA), which has 3 primary elements. The first defines what a useful PVA is; the second element provides a workflow for the design and application of a useful PVA and highlights important aspects that need to be considered during these processes; and the third element focuses on communication of PVAs to ensure clarity, comprehensiveness, repeatability, and comparability. Thereby, DAC-PVA should strengthen the credibility and relevance of PVAs for policy and management, and improve the capacity to generalize PVA findings across studies.

Since its establishment around 1990, the Ecological Conditions Database (EC; GIVD ID EU-00-006) has been accumulating vegetation relevés from the Netherlands, each accompanied by at least one abiotic soil measurement (e.g. pH or nutrient availability). On 1-1-2010, the database contained 8,229 relevés, covering the period from 1936 to 2009, and representing contributions from 110 authors. The most frequently measured soil parameter is pH, with well over 5,000 entries. All the data in the database are subjected to ISO 9001 quality control. The database can be used as the starting point for estimating plant species responses to a range of abiotic variables, such as pH, groundwater table, or nitrate concentration, and for vegetation modelling (model parameterisation and validation).

Question: Can the abiotic ranges of syntaxonomic units (associations) in terms of pH and nitrate concentration be estimated and then in principle be used to estimate critical loads for acid and nitrogen deposition?Methods: Using splines, abiotic ranges of syntaxonomic units were estimated on the basis of measured soil pH and nitrate concentration and vegetation relevés. Owing to limited calibration data, this yielded responses for only a few syntaxa. In a second attempt, we used a 160 000-relevé training set; the syntaxon of each relevé was known but not their soil pH values and soil nitrate concentrations, so for each relevé, the soil pH and nitrate concentration were estimated by inference from species composition. We again estimated abiotic ranges using the spline method, including the 5th and 95th percentiles as a proxy for the ecological range. Results:The second (indirect) method yielded ranges for soil pH and for nitrate concentration for many of the associations. The means and percentiles were corrected for regression to the mean. Conclusions:It is not yet possible to directly estimate ranges for syntaxa for pH and nitrate on a large scale from the data available. However, indirectly estimated soil pH and nitrate concentrations are sufficiently available to derive ranges for many associations. The lower (5th) percentile of the indirectly estimated pH ranges for associations may be used as the starting point for the estimation of critical loads for acid deposition. The 95th percentile should still be regarded as a rather uncertain estimate of the maximum nitrate concentration.

Weather extremes may have strong effects on biodiversity, as known from theoretical and modelling studies. Predicted negative effects of increased weather variation are found only for a few species, mostly plants and birds in empirical studies. Therefore, we investigated correlations between weather variability and patterns in occupancy, local colonisations and local extinctions (metapopulation metrics) across four groups of ectotherms: Odonata, Orthoptera, Lepidoptera, and Reptilia. We analysed data of 134 species on a 1×1 km-grid base, collected in the last 20 years from the Netherlands, combining standardised data and opportunistic data. We applied dynamic site-occupancy models and used the results as input for analyses of (i) trends in distribution patterns, (ii) the effect of temperature on colonisation and persistence probability, and (iii) the effect of years with extreme weather on all the three metapopulation metrics. All groups, except butterflies, showed more positive than negative trends in metapopulation metrics. We did not find evidence that the probability of colonisation or persistence increases with temperature nor that extreme weather events are reflected in higher extinction risks. We could not prove that weather extremes have visible and consistent negative effects on ectothermic species in temperate northern hemisphere. These findings do not confirm the general prediction that increased weather variability imperils biodiversity. We conclude that weather extremes might not be ecologically relevant for the majority of species. Populations might be buffered against weather variation (e.g. by habitat heterogeneity), or other factors might be masking the effects (e.g. availability and quality of habitat). Consequently, we postulate that weather extremes have less, or different, impact in real world metapopulations than theory and models suggest.