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Nitrogen deposition is influencing the quality of Habitat types. To assess at what deposition level the quality is influenced significantly critical loads have been estimated. To estimate the extent of the quality loss we estimated doses-response curves for nitrogen deposition per habitat type. This was done by collecting field data from empirical gradient studies and by estimating response curves for habitat types based on response curves of qualifying species per habitat type. The latter also includes a study to the response of so-called displacement species. The number of empirical studies is very limited but the results from the view that are available are very promising. Statistical relations could be estimated for 60 out of 61 nitrogen deposition sensitive habitat types occurring in the Netherlands. Comparison between the empirical and statistical relations showed that they showed very similar responses for part of the habitat types and no relation for a minor part of the types. Stikstofdepositie beïnvloedt in hoge mate de kwaliteit van habitattypen. Om te bepalen vanaf welke stikstofdepositie de kwaliteit van de habitattypen significant afneemt, zijn kritische depositiewaarden opgesteld. Om te bepalen in welke mate de kwaliteit afneemt bij stikstofdeposities hoger dan de kritische depositiewaarde, zijn er in dit onderzoek dosis-effectrelaties opgesteld. Dat is enerzijds gedaan op basis van empirische gradiëntstudies en anderzijds is verkend in hoeverre dat ook kan op basis van statistische relaties tussen het voorkomen van kwalificerende soorten van habitattypen en stikstofdepositie, waarbij ook is gekeken naar de respons van verdringingssoorten. Het aantal dosis-effectrelaties op basis van empirische studies is beperkt door gebrek aan data, maar wel zeer veelbelovend. Op basis van statistische relaties kon voor 60 van de 61 habitat(sub)typen een responscurve worden geschat. In vergelijking met de empirische relaties komen de statistische relaties voor een deel goed overeen en voor een klein deel slecht.

Aim: High levels of nitrogen deposition have been responsible for important losses of plant species diversity. It is often assumed that reduction of ammonia and nitrogen oxide emissions will result in the recovery of the former biodiversity. In Western Europe, N deposition peaked between 1980 and 1988 and declined thereafter. In a 60-year experiment in hay meadows, we tested the hypothesis that increasing and declining nitrogen deposition had negative, respectively, positive effects on plant species diversity. Location: Wageningen, the Netherlands. Method: Duplicated plots received different fertilization treatments from 1958 onwards (control, Ca, K, P, PK, N, NPK). Productivity, soil pH and species composition were measured at regular intervals. In the control plots, the correlations between N deposition, diversity, production and soil acidification were analysed. Subsequently, we tested whether the treatment effects (e.g. N addition and liming) confirmed the hypothesized interactions. Results: In the control plots, soil pH, species diversity and the abundance of legumes and short forbs declined between 1958 and 1987 when atmospheric N deposition was high but recovered after 1987 when N deposition decreased. However, also in the N addition plots species diversity recovered partly after 1987, although the soil pH of the acidified soils in these plots did not. In addition, also in the limed plots diversity decreased rapidly during the first 30 years while in this treatment soil acidification was more than compensated. Main conclusions: We conclude that declining N deposition resulted in the recovery of plant species diversity, but not in recovery of the former species composition. Time appears to be an additional, but crucial factor for the recovery of diverse, flowering meadows. Species not adapted to the new management conditions created at the start of the experiment disappeared during the first decades, while species fit for the new environment needed many years to establish.

Forest understory plant communities in the eastern United States are often diverse and are potentially sensitive to changes in climate and atmospheric inputs of nitrogen caused by air pollution. In recent years, empirical and processed-based mathematical models have been developed to investigate such changes in plant communities. In the study reported here, a robust set of understory vegetation response functions (expressed as version 2 of the Probability of Occurrence of Plant Species model for the United States [US-PROPS v2]) was developed based on observations of forest understory and grassland plant species presence/absence and associated abiotic characteristics derived from spatial datasets. Improvements to the US-PROPS model, relative to version 1, were mostly focused on inclusion of additional input data, development of custom species-level input datasets, and implementation of methods to address uncertainty. We investigated the application of US-PROPS v2 to evaluate the potential impacts of atmospheric nitrogen (N) and sulfur (S) deposition, and climate change on forest ecosystems at three forested sites located in New Hampshire, Virginia, and Tennessee in the eastern United States. Species-level N and S critical loads (CLs) were determined under ambient deposition at all three modeled sites. The lowest species-level CLs of N deposition at each site were between 2 and 11 kg N/ha/yr. Similarly, the lowest CLs of S deposition, based on the predicted soil pH response, were less than 2 kg S/ha/yr among the three sites. Critical load exceedance was found at all three model sites. The New Hampshire site included the largest percentage of species in exceedance. Simulated warming air temperature typically resulted in lower maximum occurrence probability, which contributed to lower CLs of N and S deposition. The US-PROPS v2 model, together with the PROPS-CLF model to derive CL functions, can be used to develop site-specific CLs for understory plants within broad regions of the United States. This study demonstrates that species-level CLs of N and S deposition are spatially variable according to the climate, light availability, and soil characteristics at a given location. Although the species niche models generally performed well in predicting occurrence probability, there remains uncertainty with respect to the accuracy of reported CLs. As such, the specific CLs reported here should be considered as preliminary estimates. Critical loads of atmospheric nitrogen and sulfur deposition were determined for maintaining understory vegetation diversity. Critical load exceedance was found at all model application sites.

In 2012, a controversial study on the long-term toxicity of a Roundup herbicide and the glyphosate-tolerant genetically modified (GM) maize NK603 was published. The EC-funded G-TwYST research consortium tested the potential subchronic and chronic toxicity as well as the carcinogenicity of the glyphosate-resistant genetically modified maize NK603 by performing two 90-day feeding trials, one with GM maize inclusion rates of 11 and 33% and one with inclusion rates of up to 50%, as well as a 2-year feeding trial with inclusion rates of 11 and 33% in male and female Wistar Han RCC rats by taking into account OECD Guidelines for the testing of chemicals and EFSA recommendations on the safety testing of whole-food/feed in laboratory animals. In all three trials, the NK603 maize, untreated and treated once with Roundup during its cultivation, and the conventional counterpart were tested. Differences between each test group and the control group were evaluated. Equivalence was assessed by comparing the observed difference to differences between non-GM reference groups in previous studies. In case of significant differences, whether the effects were dose-related and/or accompanied by changes in related parameters including histopathological findings was evaluated. It is concluded that no adverse effects related to the feeding of the NK603 maize cultivated with or without Roundup for up to 2 years were observed. Based on the outcome of the subchronic and combined chronic toxicity/carcinogenicity studies, recommendations on the scientific justification and added value of long-term feeding trials in the GM plant risk assessment process are presented. Electronic supplementary material The online version of this article (10.1007/s00204-019-02400-1) contains supplementary material, which is available to authorized users.

Er zijn sterke aanwijzingen dat zowel de aantallen als de soortendiversiteit van bestuivers de laatste decennia sterk achteruit zijn gegaan. Een speerpunt van de Nationale Bijenstrategie is het verbeteren van het leefgebied van wilde bijen en andere bestuivers. De meeste initiatieven om leefgebied voor wilde bijen te creëren, richten zich op het aanleggen van een bloemrijke vegetatie. Belangrijk voor wilde bijen is echter dat naast voldoende voedsel ook voldoende geschikte nestlocaties aanwezig zijn. De bekende bijenhotels helpen daarbij, maar het overgrote deel van de Nederlandse wilde bijensoorten nestelt ondergronds. Nestgelegenheid voor deze bodemnestelende bijen kan o.a. worden gecreëerd door zogenaamde nestelhoopjes of nesteldijkjes vorm te geven, maar dergelijke maatregelen zijn lang niet overal mogelijk. Een voorbeeld zijn de wegbermen, waar relatief makkelijk meer bloemaanbod te genereren is, maar gezien de verkeersveiligheid minder ruimte is voor het creëren van kale bodem of taluds. Onduidelijk is in hoeverre bloemrijke grasstroken, zoals deze wegbermen, al functioneren als nestlocatie voor wilde bijen en hoe deze potentiële functie verder kan worden bevorderd. In het voorliggende onderzoek is die vraag nader onderzocht door gedurende twee jaren in wegbermen met en zonder ingezaaide bloemranden de aanwezigheid van bodemnestelende bijen te inventariseren.

Plant species dispersal has been strongly enhanced by human activities. Introduced species have to cope with indigenous species and local conditions. They may avoid indigenous species by occupying new (abiotic) territory. Once a species is established it may become a pest, and may seriously threaten other species and ecosystems.In this paper we focus on invasive plant species of the Dutch flora. We make two comparisons: (1) Dutch neophytes (i.e. arrived in The Netherlands after 1825) vs. indigenous Dutch flora; and (2) species of the Dutch flora that have become invasive outside Europe vs. non-invasive species of the Dutch flora. We hypothesize that at least part of the success of the invasive or neophyte species is due to their ability to grow under a wider range of abiotic soil circumstances than other species. We regard an invasive species as successful if it is able to disperse from the introduction site(s) and remain present in the invaded vegetation.For ten out of the sixteen abiotic factors there is a wider range for the neophytes: chlorine, potassium, mean highest and lowest groundwater level, phosphorus (and total content) and pH H2O.We hypothesized that part of the success of invasive species may be the adaptation to a variety of abiotic soil parameters. This is indeed the case for a number of the examined parameters, mostly related to nutrient availability and soil pH. This indicates that the success of invasive species is at least partly caused by their ability to grow under a wide range of nutrient availability and soil pH. Their success may therefore be stimulated by the increasing pollution of natural areas by excessive nitrogen.

1. Agriculture benefits from ecosystem services provided by mobile agents, such as biological pest control by natural enemies and pollination by bees. However, methods that can generate spatially explicit predictions and maps of these ecosystem services based on empirical data are still scarce. 2. Here we propose a generic statistical model to derive kernel functions to characterize the spatial distribution of ecosystem services provided by mobile agents. The model is similar in spirit to a generalized linear model, and uses data of landscape composition and ecosystem services assessed at target sites to estimate parameters of the kernel. The approach is tested in a simulation study and illustrated by an empirical case study on parasitism rates of the diamondback moth Plutella xylostella. 3. The simulation study shows that the scale parameter of the exponential power kernel can be estimated with limited bias, whereas estimation of the shape parameter is difficult. For the case study the model provides biologically relevant estimates for the kernel associated with parasitism of Plutella xylostella. These estimates can be used to generate ecosystem service maps for existing or planned landscapes. The case study reveals that predictions can be sensitive to the parameter values for the width and shape of the kernel, and to the link function used in the statistical model. 4. In the last two decades numerous empirical studies assessed ecosystem services at target sites and related these to the surrounding landscape. Our method can take advantage of these data by estimating underlying kernels that can be used to map the spatial distribution of ecosystem services. However, empirical data that can discriminate between alternative kernel shapes remain critical.

European fruit tree canker, caused by Neonectria ditissima, is an important disease of pome fruit worldwide. Apple cultivars differ in their levels of susceptibility to N. ditissima. In order to design an effective plant resistance test, we examined the effectiveness of two resistance parameters: infection frequency and lesion growth. Both parameters were evaluated in parallel tests using 10 apple cultivars in three experimental years, applying seminatural infection of leaf scars (infection frequency) or inoculation of artificial wounds (lesion growth). We compared six parameters for lesion growth, of which a new parameter, lesion growth rate (LGR), appeared to be the best with respect to reproducibility and statistical significance. LGR is defined as the slope of the regression of lesion size versus time. The slope was estimated for each lesion, employing a common start date and a lesion-specific end date determined by the girdling of the lesion. The two parameters (infection frequency and LGR) were examined in separate experiments and in three successive years, and provided complementary information and resulted in reproducible conclusions on the relative resistance levels to N. ditissima of the tested cultivars. The presented methods can be used to develop strategies for the control of European fruit tree canker (e.g., in the breeding of new apple cultivars with high levels of resistance to N. ditissima).

A recent study has raised doubts about the ammonia emission reduction achieved in the Netherlands when applying manure to grassland by means of low-emission techniques such as narrow band and shallow injection. The critics claim that percentages of ammonia released to the atmosphere associated with low-emission techniques might even overlap with that from surface broadcast spreading given the large alleged experimental uncertainties in measurements. Consequently, the rationale behind the regulations to which farmers are exposed is questioned. In this study, it is shown that the alleged large uncertainties were obtained by means of an erroneous statistical method and that the real uncertainties are much smaller. It is also shown that, even when there is a large uncertainty in individual measurements, previous conclusions about differences in emission between different manure application techniques are still valid. It is further argued in this study that uncertainty in the percentage of applied ammonia emitted is implicitly taken into account in any comparative statistical analysis conducted in the past.

peer-reviewed This paper considers the statistical analysis of entomological count data from field experiments with genetically modified (GM) plants. Such trials are carried out to assess environmental safety. Potential effects on nontarget organisms (NTOs), as indicators of biodiversity, are investigated. The European Food Safety Authority (EFSA) gives broad guidance on the environmental risk assessment (ERA) of GM plants. Field experiments must contain suitable comparator crops as a benchmark for the assessment of designated endpoints. In this paper, a detailed protocol is proposed to perform data analysis for the purpose of assessing environmental safety. The protocol includes the specification of a list of endpoints and their hierarchical relations, the specification of intended levels of data analysis, and the specification of provisional limits of concern to decide on the need for further investigation. The protocol emphasizes a graphical representation of estimates and confidence intervals for the ratio of mean abundances for the GM plant and its comparator crop. Interpretation relies mainly on equivalence testing in which confidence intervals are compared with the limits of concern. The proposed methodology is illustrated with entomological count data resulting from multiyear, multilocation field trials. A cisgenically modified potato line (with enhanced resistance to late blight disease) was compared to the original conventional potato variety in the Netherlands and Ireland in two successive years (2013, 2014). It is shown that the protocol encompasses alternative schemes for safety assessment resulting from different research questions and/or expert choices. Graphical displays of equivalence testing at several hierarchical levels and their interpretation are presented for one of these schemes. The proposed approaches should be of help in the ERA of GM or other novel plants.

In 2012, a controversial study on the long-term toxicity of a Roundup herbicide and the glyphosate-tolerant genetically modified (GM) maize NK603 was published. The EC-funded G-TwYST research consortium tested the potential subchronic and chronic toxicity as well as the carcinogenicity of the glyphosate-resistant genetically modified maize NK603 by performing two 90-day feeding trials, one with GM maize inclusion rates of 11 and 33% and one with inclusion rates of up to 50%, as well as a 2-year feeding trial with inclusion rates of 11 and 33% in male and female Wistar Han RCC rats by taking into account OECD Guidelines for the testing of chemicals and EFSA recommendations on the safety testing of whole-food/feed in laboratory animals. In all three trials, the NK603 maize, untreated and treated once with Roundup during its cultivation, and the conventional counterpart were tested. Differences between each test group and the control group were evaluated. Equivalence was assessed by comparing the observed difference to differences between non-GM reference groups in previous studies. In case of significant differences, whether the effects were dose-related and/or accompanied by changes in related parameters including histopathological findings was evaluated. It is concluded that no adverse effects related to the feeding of the NK603 maize cultivated with or without Roundup for up to 2 years were observed. Based on the outcome of the subchronic and combined chronic toxicity/carcinogenicity studies, recommendations on the scientific justification and added value of long-term feeding trials in the GM plant risk assessment process are presented., This study was carried out as part of the G-TwYST project (“GM Plant Two Year Safety Testing”), financially supported by the Seventh Framework Programme of the European Community for Research, Technological Development and Demonstration Activities (FP7), Grant Agreement No. 632165.

De kern van weidevogelbeheer betreft in Nederland het op orde krijgen van de habitatkwaliteit in de graslanden. Eerdere ervaringen laten zien dat NDVI-satellietbeelden een belangrijke rol kunnen spelen om hier gebiedsdekkend inzicht in te krijgen. In dit onderzoek is op een aantal onderdelen getoetst in hoeverre deze beelden inzicht geven in de feitelijke situatie en in hoeverre ze een betrouwbaar hulpmiddel kunnen zijn bij het plannen en evalueren van weidevogelbeheer. In een eerste analyse is vastgesteld in hoeverre NDVI specifiek is voor het type grasland. Daarnaast is onderzocht in hoeverre NDVI indicerend is voor zwaarte (biomassa) en structuur van de vegetatie, de kruidenrijkdom en de doorwaadbaarheid van de vegetatie (als maat voor verplaatsingsweerstand voor kuikens). Ten slotte is in beeld gebracht hoe de verspreiding van weidevogels gedurende het broed- en opgroeiseizoen samenhangt met de NDVI-waarden. Voor alle aspecten is een (vrij) sterke, vaak significante samenhang gevonden. Daarmee lijken NDVI-beelden bruikbaar om een gebiedsdekkend, realistisch beeld van de feitelijke situatie te geven.

The apparent nitrogen fertilizer replacement value of farmyard manure (NFRVFYM) was studied in a long-term experiment on a loamy sand soil at Grabow, Poland. The experiment combined five rates of FYM with four nitrogen (N) fertilizer rates in two rotations (RotA and RotB) started in 1980 (Expt1) and, in parallel, 1981 (Expt2). Rotations consisted of potatoes, winter wheat and spring barley, followed by silage maize (RotA) or grass-clover ley (GCL, RotB). We analysed six consecutive cycles. NFRVFYM was much larger in RotB than RotA, due to high N supply from GCL residues combined with likely deficiencies in potassium (K) and/or phosphorus (P), causing weak crop responses to N fertilizer in RotB relative to FYM effects. Devoid of non-N effects, 'true' (as opposed to apparent) NFRVFYM was estimated at 2.0 kg fertilizer-N per tonne of FYM (at equal N offtake), or 2.7 kg/t (at equal DM yield). These values correspond with equivalencies of 0.37 and 0.50 kg fertilizer-N per kg FYM-N. RotB required 25 kg P and 350 kg K/ha/cycle more input than RotA to compensate for higher P and K offtake in GCL compared to maize. The study highlights differences between approaches to assess NFRVFYM, giving larger values at high compared with low N fertilizer rate, and larger values at low compared with high FYM rate. These contrasts reflect drift in the ratio between the agronomic N-use efficiencies of FYM and fertilizer, respectively, and in the ratio between the apparent recoveries of N from these sources. Journal compilation

Safety assessments guard against unintended effects for human health and the environment. When new products are compared with accepted reference products by broad arrays of measurements, statistical analyses are usually summarised by significance tests or confidence intervals per endpoint. The traditional approach is to test for statistical significance of differences. However, absence or presence of significant differences is not a statement about safety. Equivalence limits are essential for safety assessment. We propose graphs to present the results of equivalence tests over the array of endpoints. It is argued that plots of the equivalence limit scaled difference (ELSD) are preferable over plots of the standardised effect size (SES) used previously for similar assessments. The ELSD method can be used either with externally specified equivalence limits or with equivalence limits estimated from (historical) data. The method is illustrated with two examples: first, environmental safety of MON810 Bt maize was assessed using field trial count data of arthropods; second, human safety of herbicide tolerant NK603 maize was assessed using haematological, biochemical and organ weight data from a 90-day rat feeding study. All assessed endpoints were classified in EFSA equivalence categories I or II, implying full equivalence or equivalence more likely than not.

Potato late blight disease remains the primary stressor of commercial potato production across the EU, typically requiring >10 fungicide applications per growing season to offset crop losses. In response, the goal of this study was to test and validate a novel, more durable, control strategy for potato late blight. This IPM2.0 strategy is based on the principles of Integrated Pest Management (IPM) which sees the deployment of a late blight resistant potato genotype, a cisgenically modified, Desiree based resistant potato line here, in conjunction with pathogen population monitoring for virulence to the resistance genes (R genes) deployed and a “do not spray unless”, low input fungicide spray strategy. Field evaluations were completed in the Netherlands and in Ireland in 2013, 2014 and in Ireland in 2015. Comparators used in this study included the original but susceptible potato variety Desiree and the conventional but highly resistant variety Sarpo Mira. The novel IPM2.0 strategy was compared to local common practice (fungicide applications on a near weekly basis) and an untreated control. Overall, the IPM2.0 control strategy validated here reduced the average fungicide input by 80–90% without compromising control efficacy. Corresponding environmental side-effects were reduced proportionally. The results underline the pragmatic role host resistance can provide to commercial potato production systems and to society at large if employed as part of an integrated late blight control system.

Field data on ammonia emission after liquid cattle manure (‘slurry’) application to grassland were statistically analysed to reveal the effect of manure and field characteristics and of weather conditions in eight consecutive periods after manure application. Logistic regression models, modelling the emission expressed as a percentage of the ammonia still present at the start of each period as the response variable, were developed separately for broadcast spreading, narrow band application (trailing shoe) and shallow injection. Wind speed, temperature, soil type, total ammoniacal nitrogen (TAN) content and dry matter content of the manure, application rate and grass height were selected as significant explanatory variables. Their effects differed for each application method and among periods. Temperature and wind speed were generally the most important drivers for emission. The fitted regression models were used to reveal seasonal trends in NH3 emission employing historical meteorological data for the years 1991–2014. The overall average emission was higher in early and midsummer than in early spring and late summer. This seasonal trend was most pronounced for broadcast spreading followed by narrow band application, and was almost absent for shallow injection. However, due to the large variation in weather conditions, emission on a particular day in early spring can be higher than on a particular day in summer. The analysis further revealed that, in a specific scenario and depending on the application technique, emission could be reduced with 20–30% by restricting manure application to favourable days, i.e. with weather conditions with minimal emission levels.

Publications on power analyses for field trial count data comparing transgenic and conventional crops have reported widely varying requirements for the replication needed to obtain statistical tests with adequate power. These studies are critically reviewed and complemented with a new simulation study. The reasons for the different reports are elucidated and can be classified as additional (but hidden) replication, selection of favourable endpoints with low variation, and reporting at an unusual scale. A new simulation study was performed to investigate the relationship between statistical power and replication under a variety of data-generating and analysis methods. Approximately 60 replications should be sufficient to detect a 50% (two-fold) decrease in taxon numbers, provided that the coefficient of variation in the counts does not exceed 100%. Replication can be accomplished not only by using multiple blocks in a single trial, but also by repeating the experiment in multiple years and/or at different sites. With other (e.g. agronomic) treatment factors in the field trial, without interaction with variety, the effective replication can be increased by investigating the main variety effect summed over the other treatment factors. Repeated measures may also increase the power if the expected difference is equal over time and the time points are sufficiently spaced.

Apparent nitrogen fertilizer replacement values of grass-clover leys (NFRV GCL ) and farmyard manure (NFRV FYM ) were studied in a long-term (24 years) experiment. This paper reports the results for grass-clover leys (GCL). Five rates of farmyard manure (FYM) and four rates of fertilizer nitrogen (N) were applied to two arable rotations (RotA - arable+silage maize; RotB - arable+GCL). Polynomial response surfaces fitted to dry matter (DM) yield and N offtake in the three arable crops were used to assess NFRV GCL by interpolation, at high (Method H) and low (Method L) N fertilizer rates, always comparing RotA and RotB at equal FYM rates. In Expt1 (started in 1980), arable crops in RotB required 188, 246, 270, 295 and 312 kg N/ha less fertilizer per cycle than in RotA, to match the DM yields found at highest fertilizer rate in RotA (Method H). These values refer to FYM rates of 0, 20, 40, 60 and 80 t/ha per cycle, respectively. Corresponding fertilizer savings in Expt2 (started in 1981) were 287, 323, 341, 346 and 337 kg N/ha per cycle. These NFRV GCL values represent savings of 50-83% (Expt1) or 77-92% (Expt2) in N fertilizer applied to the arable phase. Slightly lower NFRV GCL was found by Method L. Extra N offtake in RotB over RotA was a poor estimator of NFRV GCL , showing much lower values and different responses to FYM and fertilizer than NFRV GCL . Mixed leys enable large fertilizer savings in arable rotations. Journal compilation

Climate change will affect mycotoxin contamination of feed and food. Mathematical models for predicting mycotoxin concentrations in cereal grains are useful for estimating the impact of climate change on these toxins. The objective of the current study was to construct a descriptive model to estimate climate change impacts on deoxynivalenol (DON) contamination of mature wheat grown in northwestern Europe. Observational data from 717 wheat fields in Norway, Sweden, Finland, and The Netherlands were analyzed, including the DON concentrations in mature wheat, agronomical practices, and local weather. Multiple regression analyses were conducted, and the best set of explanatory variables, mainly including weather factors, was selected. The final model included the following variables: flowering date, length of time between flowering and harvest, wheat resistance to Fusarium infection, and several climatic variables related to relative humidity, temperature, and rainfall during critical stages of wheat cultivation. The model accounted for 50 % of the variance, which was sufficient to make this model useful for estimating the trends of climate change on DON contamination of wheat in northwestern Europe. Application of the model in possible climate change scenarios is illustrated.

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? Location: Europe. Methods: Using splines, abiotic ranges of syntaxonomic units were estimated on the basis of measured soil pH and nitrate concentration and vegetation releves. Owing to limited calibration data, this yielded responses for only a few syntaxa. In a second attempt, we used a 160 000-releve training set; the syntaxon of each releve was known but not their soil pH values and soil nitrate concentrations, so for each releve, 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

We studied dispersal of Great Reed Warblers Acrocephalus arundinaceus, using a mark–resight model for dispersal. We assessed the relevance of ecological distance, defined as movement along reed edges, as opposed to straight line distance for predicting the distribution of dispersal. In a mark–resight study in the northern Netherlands, 1158 birds were ringed. 178 birds were resighted at least once, with 254 movements between known nesting locations in successive years. Dispersal was defined as movement between successive nesting sites, and modelled as an exponential function of ecological and geographical distances. To correctly model dispersal probabilities in the fragmented study area, the model discriminates between suitable habitat sections and intermediate gaps. Several nested models for dispersal were compared by means of the likelihood ratio test. Models incorporating ecological distance gave a better fit than models using geographical distance, although the difference was not large. To describe dispersal probabilities, combined models were necessary at both local and long distance scales, and separate models were needed for juveniles and adults. For a landscape without gaps, the parameter estimates of the best model can be interpreted as follows. An estimated 65% of the adult dispersal distances were within a close range of the previous nesting location with a mean ecological dispersal distance of 0.58 km. The remaining 35% had an estimated mean distance of 10.3 km. An estimated 39% of the juvenile movements were random over the study area. The remaining 61% had a mean dispersal distance of 3.1 km. These results suggest that there might be two dispersal strategies in the Great Reed Warbler. There is also an indication that adults disperse further when connectivity decreases. These findings indicate that dispersal of Great Reed Warblers is not random, but smaller dispersal distances are more likely than larger distances. This might result in a limited dispersal ability of the species over the fragmented landscape.

Landscapes are composed of a multitude of habitat types which, potentially, can influence natural enemy populations. The contribution of specific habitat types to sustaining natural enemy populations in agricultural landscapes and the associated ecosystem service of pest control is not well understood. We investigated how landscape composition affected parasitism rates in 22 organic Brussels sprout fields in The Netherlands. Second and third instar larvae of Plutella xylostella were placed on experimental Brussels sprout plants in Brussels sprout fields and were recovered after two days in the field. Parasitism rates ranged between 4 and 94% and were related to landscape variables at a scale of 0.3, 1, 2 and 10 km. Univariate analysis using a generalized linear mixed model indicated that parasitism rates were positively related with area of forests at a scale of 1, 2 and 10 km, forest edges at a scale of 1 and 2 km and road verges at a scale of 1 km. Forest and road verges are likely to provide food and alternative hosts for parasitoids and are less disturbed habitats than agricultural fields. These results suggest that forests and road verges may play an important role in sustaining effective densities of parasitoids of P. xylostella in agricultural landscapes.

Pesticide risk assessment is hampered by worst-case assumptions leading to overly pessimistic assessments. On the other hand, cumulative health effects of similar pesticides are often not taken into account. This paper describes models and a web-based software system developed in the European research project ACROPOLIS. The models are appropriate for both acute and chronic exposure assessments of single compounds and of multiple compounds in cumulative assessment groups. The software system MCRA (Monte Carlo Risk Assessment) is available for stakeholders in pesticide risk assessment at mcra.rivm.nl. We describe the MCRA implementation of the methods as advised in the 2012 EFSA Guidance on probabilistic modelling, as well as more refined methods developed in the ACROPOLIS project. The emphasis is on cumulative assessments. Two approaches, sample-based and compound-based, are contrasted. It is shown that additional data on agricultural use of pesticides may give more realistic risk assessments. Examples are given of model and software validation of acute and chronic assessments, using both simulated data and comparisons against the previous release of MCRA and against the standard software DEEM-FCID used by the Environmental Protection Agency in the USA. It is shown that the EFSA Guidance pessimistic model may not always give an appropriate modelling of exposure.

Question: The use of expert-based indicator values to estimate abiotic conditions from vegetation is widespread. However, recent research has shown that expert judgement may contain considerable bias and thereby introduces a large amount of uncertainty. Could expert based indicator values be replaced by indicator values based on field measurements? Location: Europe. Methods: We developed a method to estimate species response based on measured physical data, and a method to predict abiotic conditions from the vegetation composition using these responses. This method was tested for soil pH. Results: We were able to estimate the pH response of 556 species of the Dutch flora. Ca. 20% of the responses were, at least, bimodal and many responses had a very wide range. The simplest method ('raw mean') yielded the best prediction of pH; the indicator value of a species is the mean of the soil pH values of the sites where it was observed. A list of all raw-mean estimates per species is given. The predicted pH of a new site is the mean of the indicator values of the present species. The estimated species responses were validated on independent Dutch and European data sets. Older successional stages seem to be predicted better than younger stages. Conclusions: Our method performed better than the popular Ellenberg indicator system for the Dutch data set, while being just as easy to use, because it only needs a single value per species. We foresee that, when more data become available, our method has the potential to replace the Ellenberg system.

Smart & Scott (2004, this issue) criticized our paper (Wamelink et al. 2002) about the bias in average Ellenberg indicator values. Their main criticism concerns the method we used, regression analysis. They state the bias can be mimicked by the construction of an artificial data set and that regression analysis is not a suited tool to investigate underlying phenomena. Moreover they claim that the present bias is caused by the distribution of Ellenberg indicator values between syntaxa, instead of a bias in average Ellenberg indicator values per species. We show that their criticism of the use of regression analysis does not hold. We selected average Ellenberg values per vegetation group for several pH classes and applied an F-test to determine whether or not the vegetation groups within each pH class differed significantly from each other. This was the case for all tested classes (P

Biodiversity, including plant species diversity, is threatened worldwide as a result of anthropogenic pressures such as an increase of pollutants and climate change. Rare species in particular are on the verge of becoming extinct. It is still unclear as to why some plant species are rare and others are not. Are they rare due to: intrinsic reasons, dispersal capacity, the effects of management or abiotic circumstances? Habitat preference of rare plant species may play an important role in determining why some species are rare. Based on an extensive data set of soil parameters we investigated if rarity is due to a narrow habitat preference for abiotic soil parameters. For 23 different abiotic soil parameters, of which the most influential were groundwater-table, soil-pH and nutrient-contents, we estimated species responses for common and rare species. Based on the responses per species we calculated the range of occurrence, the range between the 5 and 95 percentile of the response curve giving the habitat preference. Subsequently, we calculated the average response range for common and rare species. In addition, we designed a new graphic in order to provide a better means for presentation of the results. The habitat preferences of rare species for abiotic soil conditions are significantly narrower than for common species. Twenty of the twenty-three abiotic parameters showed on average significantly narrower habitat preferences for rare species than for common species; none of the abiotic parameters showed on average a narrower habitat preference for common species. The results have major implications for the conservation of rare plant species; accordingly management and nature development should be focussed on the maintenance and creation of a broad range of environmental conditions, so that the requirements of rare species are met. The conservation of (abiotic) gradients within ecosystems is particularly important for preserving rare species.

Genetic modification of plants may result in unintended effects causing potentially adverse effects on the environment. A comparative safety assessment is therefore required by authorities, such as the European Food Safety Authority, in which the genetically modified plant is compared with its conventional counterpart. Part of the environmental risk assessment is a comparative field experiment in which the effect on non-target organisms is compared. Statistical analysis of such trials come in two flavors: difference testing and equivalence testing. It is important to know the statistical properties of these, for example, the power to detect environmental change of a given magnitude, before the start of an experiment. Such prospective power analysis can best be studied by means of a statistical simulation model. This paper describes a general framework for simulating data typically encountered in environmental risk assessment of genetically modified plants. The simulation model, available as Supplementary Material, can be used to generate count data having different statistical distributions possibly with excess-zeros. In addition the model employs completely randomized or randomized block experiments, can be used to simulate single or multiple trials across environments, enables genotype by environment interaction by adding random variety effects, and finally includes repeated measures in time following a constant, linear or quadratic pattern in time possibly with some form of autocorrelation. The model also allows to add a set of reference varieties to the GM plants and its comparator to assess the natural variation which can then be used to set limits of concern for equivalence testing. The different count distributions are described in some detail and some examples of how to use the simulation model to study various aspects, including a prospective power analysis, are provided. © 2014 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.

When humans will settle on the moon or Mars they will have to eat there. Food may be flown in. An alternative could be to cultivate plants at the site itself, preferably in native soils. We report on the first large-scale controlled experiment to investigate the possibility of growing plants in Mars and moon soil simulants. The results show that plants are able to germinate and grow on both Martian and moon soil simulant for a period of 50 days without any addition of nutrients. Growth and flowering on Mars regolith simulant was much better than on moon regolith simulant and even slightly better than on our control nutrient poor river soil. Reflexed stonecrop (a wild plant); the crops tomato, wheat, and cress; and the green manure species field mustard performed particularly well. The latter three flowered, and cress and field mustard also produced seeds. Our results show that in principle it is possible to grow crops and other plant species in Martian and Lunar soil simulants. However, many questions remain about the simulants' water carrying capacity and other physical characteristics and also whether the simulants are representative of the real soils.

The increased variability in weather as a manifestation of climate change is expected to have negative impacts on population survival in wildlife species, because it will likely lead to increased variation in vital demographic rates (mortality and reproduction) in these populations. For the effective protection of biodiversity, adaptation measures are needed to compensate for the expected increase in weather variability and the negative interaction with habitat fragmentation. As a case study, we studied the fluctuations in Great Bittern numbers (Botaurus stellaris) from 28 monitoring plots scattered over the Netherlands to explore the interaction between the effect of weather and possible remediating effects of the landscape structure. Great Bittern habitat surrounding these plots differs with respect to area, quality, and degree of isolation of this habitat. In western Europe, Great Bitterns are found to be susceptible to continuous loss of suitable habitat due to vegetation succession and fragmentation. Moreover, year-to-year fluctuations in local Great Bittern populations can be caused by severe winter weather or other weather extremes. Our results show that severe winter weather has indeed a significant negative impact on Great Bittern population growth rates. Furthermore, we found that an increased carrying capacity and spatial cohesion (i.e. inverse of habitat fragmentation) contribute to an increase in mean growth rates over the years. As growth rates are higher in large, well-connected habitats, we argue that recovery from negative effects of, e.g. severe winters on Great Bittern population numbers is enhanced in these less-fragmented habitats. We derived generic adaptation measures for enhancing the recovery rate of populations of species in general: one should invest in more large, well-connected nature areas, not only to diminish the negative effects of habitat fragmentation on wildlife populations, but additionally to reduce the impacts of climatic variability.

Summary There is a general lack of information on how international conservation treaties affect biodiversity. The Ramsar convention on the protection of internationally important wetlands is such an international conservation policy. It initiated the world-wide establishment of over 2000 protected areas currently covering more than 200 million ha. The convention came into force in 1975, but to date, it remains unknown whether it actually produces biodiversity benefits. We analysed 21 years of survey data from a wide range of waterbird species in over 200 Moroccan wetlands and examined whether Ramsar designation as well as a national protected areas programme Sites d'InteretBiologique et Ecologique (SIBE) positively affected bird abundance. Furthermore, habitat characteristics of wetlands in protected areas and control sites were compared and bird abundance was related to habitat characteristics. After designation, waterbird species richness and abundance increased more rapidly in Ramsar wetlands than in non-designated wetlands. In SIBE sites, increases in bird abundance were intermediate. Waterbird abundance was significantly related to habitat characteristics, most importantly cover of water or bare ground. Compared to control sites, Ramsar sites had significantly higher cover of habitat types favoured by most waterbird species. It remained unclear, however, whether these differences were caused by conservation management or were already present prior to conservation designation. Surprisingly, waterbird population trends in Moroccan wetlands were markedly positive. Trends were found to be related to precipitation levels in the Sahel which may have caused changes in migratory strategies. Synthesis and applications. This study demonstrates a powerful approach to systematically evaluating biodiversity responses to major international conservation policies. The results highlight that data on management and habitat quality are critical for reaching general conclusions about the effectiveness of conservation instruments. Site managers or conservation authorities should be encouraged to collect standardized data on conservation actions to help interpret the mechanisms behind population responses and thus extrapolate findings beyond the study system. These findings represent a first small step towards unravelling the contribution of international conservation tools towards global policy objectives of halting the biodiversity decline.

The diving behaviour of 25 harbour seals, Phoca vitulina (14 females and 11 males), of various body lengths was monitored by means of VHF telemetry at different locations in the Wadden Sea during late autumn in 1991 and 1992. Median dive durations for individual seals ranged from 46 s to 2.9 min. The maximum dive recorded was 31 min, performed by an adult male, which represents the longest dive reported for harbour seals. Dive endurance increased significantly in relation to body length. Female harbour seals tended to perform fewer short dives and had a more narrow distribution of dive times. We detected no diurnal differences in dive behaviour and only the ambient air temperature was found to influence the duration of surface periods, in that surface intervals tended to be shorter when temperatures were below 9 °C. The overall mean percentage of dive time was 85%, with individuals varying from 76 to 93%, and was in general higher in females.

The present document has been produced and adopted by the bodies identified above as author(s). In accordance with Article 36 of Regulation (EC) No 178/2002, this task has been carried out exclusively by the author(s) in the context of a grant agreement between the European Food Safety Authority and the author(s). The present document is published complying with the transparency principle to which the Authority is subject. It cannot be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.

The present document has been produced and adopted by the bodies identified above as author(s). In accordance with Article 36 of Regulation (EC) No 178/2002, this task has been carried out exclusively by the author(s) in the context of a grant agreement between the European Food Safety Authority and the author(s). The present document is published complying with the transparency principle to which the Authority is subject. It cannot be considered as an output adopted by the Authority. The European Food Safety Authority reserves its rights, view and position as regards the issues addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.

Mineral carbonation of basic silicate minerals regulates atmospheric CO(2) on geological time scales by locking up carbon. Mining and spreading onto the earth's surface of fast-weathering silicates, such as olivine, has been proposed to speed up this natural CO(2) sequestration ('enhanced weathering'). While agriculture may offer an existing infrastructure, weathering rate and impacts on soil and plant are largely unknown. Our objectives were to assess weathering of olivine in soil, and its effects on plant growth and nutrient uptake. In a pot experiment with perennial ryegrass (Lolium perenne L.), weathering during 32 weeks was inferred from bioavailability of magnesium (Mg) in soil and plant. Olivine doses were equivalent to 1630 (OLIV1), 8150, 40700 and 204000 (OLIV4) kg ha(-1). Alternatively, the soluble Mg salt kieserite was applied for reference. Olivine increased plant growth (+15.6%) and plant K concentration (+16.5%) in OLIV4. At all doses, olivine increased bioavailability of Mg and Ni in soil, as well as uptake of Mg, Si and Ni in plants. Olivine suppressed Ca uptake. Weathering estimated from a Mg balance was equivalent to 240 kg ha(-1) (14.8% of dose, OLIV1) to 2240 kg ha(-1) (1.1%, OLIV4). This corresponds to gross CO(2) sequestration of 290 to 2690 kg ha(-1) (29 10(3) to 269 10(3) kg km(-2).) Alternatively, weathering estimated from similarity with kieserite treatments ranged from 13% to 58% for OLIV1. The Olsen model for olivine carbonation predicted 4.0% to 9.0% weathering for our case, independent of olivine dose. Our % values observed at high doses were smaller than this, suggesting negative feedbacks in soil. Yet, weathering appears fast enough to support the 'enhanced weathering' concept. In agriculture, olivine doses must remain within limits to avoid imbalances in plant nutrition, notably at low Ca availability; and to avoid Ni accumulation in soil and crop.

In order to map the spatial distribution of twenty tree species groups over Europe at 1 km × 1 km resolution, the ICP-Forest Level-I plot data were extended with the National Forest Inventory (NFI) plot data of eighteen countries. The NFI grids have a much smaller spacing than the ICP grid. In areas with NFI plot data, the proportions of the land area covered by the tree species were mapped by compositional kriging. Outside these areas, these proportions were mapped with a multinomial multiple logistic regression model. A soil map, a biogeographical map and bioindicators derived from temperature and precipitation data were used as predictors. Both methods ensure that the predicted proportions are in the interval [0,1] and sum to 1. The regression predictions were iteratively scaled to the National Forest Inventory statistics and the Forest map of Europe. The predicted proportions for the twenty tree species were validated by the Bhattacharryya distance between predicted and observed proportions at 230 plot data separated from the calibration data. Besides, the map with the predicted dominant species was validated by computing the error matrix. The median Bhattacharryya distance in the subarea with NFI plot data was 1.712, whereas in the subarea with ICP-Level-I data, this was 2.131. The scaling did not significantly decrease the Bhattacharryya distance. The estimated overall accuracy of this map was 43%. In areas with NFI plot data, overall accuracy was 57%, outside these areas 33%. This gain was mainly attributable to the much denser plot data, less to the prediction method.

Most recent information on the occurrence of Fusarium Head Blight species and related mycotoxins in wheat grown in the Netherlands dates from 2001. This aim of this study was to investigate the incidence and levels of Fusarium Head Blight species and Fusarium mycotoxins, as well as their possible relationships, in winter wheat cultivated in the Netherlands in 2009. Samples were collected from individual fields of 88 commercial wheat growers. Samples were collected at harvest from 86 fields, and 2 weeks before the expected harvest date from 21 fields. In all, 128 samples, the levels of each of seven Fusarium Head Blight species and of 12 related mycotoxins were quantified. The results showed that F. graminearum was the most frequently observed species at harvest, followed by F. avenaceum and M. nivale. In the pre-harvest samples, only F. graminearum and M. nivale were relevant. The highest incidence and concentrations of mycotoxins were found for deoxynivalenol, followed by zearalenone and beauvericin, both pre-harvest and at harvest. Other toxins frequently found – for the first time in the Netherlands – included T-2 toxin, HT-2 toxin, and moniliformin. The levels of deoxynivalenol were positively related to F. graminearum levels, as well as to zearalenone levels. Other relationships could not be established. The current approach taken in collecting wheat samples and quantifying the presence of Fusarium Head Blight species and related mycotoxins is an efficient method to obtain insight into the occurrence of these species and toxins in wheat grown under natural environmental conditions. It is recommended that this survey be repeated for several years to establish inter-annual variability in both species composition and mycotoxin occurrence.

Shellfish products may be contaminated with marine biotoxins which, after consumption, may lead to human illness. The Netherlands has a regular monitoring programme for marine biotoxins and the possible toxic phytoplankton in shellfish production waters. The aim of the current study was to evaluate the presence of potential toxic phytoplankton species and marine biotoxins in Dutch production waters over the last decade, and to analyse the relationship between toxin levels and abundance of possible causative phytoplankton species. The results of the monitoring programme of the period 1999-2009 were used. The presence of Alexandrium spp. were negligible, but Pseudo-nitzschia spp. and phytoplankton causing diarrhetic shellfish poisoning (DSP toxin-producing phytoplankton) were present in nearly all three main production areas and years. The main DSP toxin-producing species was Dinophysis acuminata followed by D. rotundata and Prorocentrum lima. Toxins causing paralytic shellfish poisoning (PSP) and amnesic shellfish poisoning (ASP) were present in only a few individual shellfish samples, all at low levels. At the end of 2002, an episode of DSP toxicity was recorded, based on the rat bioassay results. Of the samples that were chemically analysed for DSP toxins in 2007 and 2008, about half of the samples in 2007 contained these toxins, although levels were low and no positive results were obtained using the rat bioassay. There was a slight positive correlation between concentrations of DSP toxin-producing phytoplankton and levels of DSP toxins in 2007. Increased DSP toxin levels were found up to 5 weeks after the peak in DSP toxin-producing phytoplankton. This positive, but weak, relationship needs to be confirmed in future research using more samples and chemical methods to quantify the presence of DSP toxins. If this relationship is further substantiated and quantified, it could be used within the current monitoring programme in the Netherlands to predict the risk areas regarding DSP toxicity in shellfish.