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© 2017 The Authors Reproductive isolation caused by divergent natural selection arising from differences between ecological environments or ecological interactions represents a major mechanism contributing to speciation, but its relative importance is poorly known. In this study, controlled reciprocal crossings and seed germination experiments were combined with genetic and morphometric analyses to test the hypothesis that previously described differences in mycorrhizal communities between forest and dune ecotypes of Epipactis helleborine were sufficiently strong to create complete reproductive isolation between the two ecotypes. Molecular analyses using 770 SNP markers showed that the two ecotypes were genetically distinct and that populations of the dune ecotype were genetically impoverished compared to populations of the forest ecotype. Morphologically, the two ecotypes were also significantly different, with plants of the dune ecotype generally being smaller than plants of the forest ecotype. The results further showed that immigrant seeds had a significantly lower probability of protocorm formation than native seeds, indicating strong immigrant inviability. Although both ecotypes were able to cross easily and to produce a large number of viable seeds, hybrid seeds showed significantly lower protocorm formation than pure seeds, further contributing to reproductive isolation. Overall, these results indicate that interfertile populations of a widespread orchid adapting to contrasting environments diverge as a consequence of concurrent selection acting against immigrants and hybrids and suggest that mycorrhizal fungi can play a role in the early stages of plant speciation. ispartof: Oikos vol:127 issue:1 pages:73-84 status: published

An increasing number of regulatory tools aiming to impose preventive and control actions against invasive species are currently being developed in Europe. Both species prioritization and the choice of best preventive and potential control actions to reduce the risk require robust and transparent risk assessment. Two different generic tools, available from http://ias.biodiversity.be, have recently been developed in Belgium to help decision makers reaching these goals, i.e. a quick screening prioritization process (Harmonia+) and a detailed risk assessment scheme. Both tools may be applied to any non-native organism irrespective its taxonomic affiliation and encompass an evaluation of the probability of organism entry, establishment, spread, and of the potential and magnitude of environmental, economic and social consequences including plant, animal and human health. Harmonia+ is a quick screening tool that may be used for different purposes (D’hondt et al. 2014): (i) the elaboration of priority lists of invasive species that are established or could potentially establish in an area, (ii) the fulfillment of rapid assessment to help conservation managers to prioritize actions when a new non-native organism is found in the wild and (iii) the identification of non-native species with the highest priority for in-depth and time consuming risk analyses and (iv) the scoring of probability and magnitude of the different elements included in those risk analyses.The detailed scheme for invasive species risk analysis is based on the recommendations of the international standards for pest risk analysis for organisms of quarantine concern produced by the Secretariat of the International Plant Protection Convention. It follows a process defined by two main stages, i.e. the risk assessment stage itself and the risk management stage, which involves identifying options for reducing the identified risks. This detailed analysis is especially valuable to know whether trade restrictions could be considered as adequate and efficient to reduce the risk.The output of the risk assessments based on these new tools will be presented and discussed for five emerging non-native species in Belgium (water primrose, red swamp crayfish, American bullfrog, sacred ibis and raccoon dog). Different recommendations and priorities for decision making will be provided for the different species based on the outcome of these analyses. Potential uses for the selection of species of EU concern in the framework of the new EC proposal of Regulation on the prevention and management of the introduction and spread of IAS in Europe will also be discussed.

Rapid detection of potentially harmful invasive alien species (IAS) is essential to avoid future invasions and management costs. Until recently, the Flemish region (Flanders, Northern Belgium) - and by extension Belgium - had no dedicated portal for reporting observations of such species, despite the high political priority and ongoing current (inter) national initiatives. In 2011, the Agency for Nature and Forest and the Institute for Nature and Forest Research initiated a pilot. For some notorious IAS, an early warning system was launched through the widely used online recording platform www.waarnemingen.be. The system is primarily targeted towards naturalist observers. This was done in cooperation with all Belgian regions and the major non-governmental organisations in the field of nature conservation. The system allows for reporting sightings, consulting fact sheets and setting up user-driven automated e-mail alerts. The aim of the pilot phase (March-November 2012) was to examine how the system could work (which species are picked up, potential reporting bias, data quality). Apart from testing the reporting tool as an early warning system, the project had several spin-offs. In the longer run, we aimed at mobilizing volunteers for monitoring IAS. We also wanted to provide information and raise awareness amongst field workers and the public. Eventually, we hope to streamline the process from reporting to management intervention. The ultimate goal is to have an early warning system for IAS in Flanders (northern Belgium) that connects with federal initiatives and anticipates developments of a trans-European system. The current system is already being used for various rapid response projects in Flanders, including control of invasive aquatic plants such as floating pennywort Hydrocotyle ranunculoides, water primrose Ludwigia grandiflora, Parrot’s feather Myriophyllum aquaticum, ruddy duck Oxyura jamaicensis, Pallas’ squirrel Callosciurus erythreaus, quarantine insects, American bullfrog Lithobates catesbeianus, giant hogweed Heracleum mantegazzianum and Chinese muntjac Muntiacus reevesi.

Since the 1980s, the European eel Anguilla anguilla stock is in steep decline. Lipid reserves are essential to cover energetic requirements for silver eel migration and reproduction. Two large and independent data sets from Belgium and The Netherlands show an average one-third decrease in fat contents of yellow eels over the past 15 years. Also Le Cren’s relative condition factor decreased. On the basis of the somatic energy reserves, reproductive potential of eels from various latitudes over Europe was estimated, assuming fat levels in yellow eel are indicative of those in silver eels. Only large individuals, females as well as males, with high lipid content seem to be able to contribute to the spawning stock. The decrease in fat content in yellow eels may be a key element in the stock decline and raises serious concerns about the chances of the stock to recover.

Coastal dunes are a unique ecosystem and home to a large number of red list species. Embryonic dunes, shifting white or fixed grey dunes, humid and wet dune slacks, dune grasslands and moss dunes are high conservation value habitats of European importance. However, many of the dune areas are small and fragmented, making them very susceptible to external influences. Surveys have shown that the surrounding gardens are an important source of invasive plant species occurring in these natural areas. Some of these plants, such as black cherry Prunus serotina, Ribes aureum, Cotoneaster spp. and exotic Populus spp. are starting to cause problems for native biodiversity. Detailed monitoring shows that some of these species are starting to display invasive behaviour. Therefore, there is an urgent need amongst conservation managers for detailed data on efficiency of potential management measures. The non-native North American Oregon grape (Mahonia aquifolium) is such a species. This evergreen shrub is a very popular garden plant in the area. It grows vigorously on sandy soil along the coast and with its yellow flowers has great ornamental value. However, with its strong clonal growth it can strongly proliferate and overgrow native vegetation. Furthermore, its blue berries are easily spread by birds. Little is known about management of this invasive species. Therefore, within RINSE, an experiment was set up in three heavily infested dune reserves. Individual Mahonia shrubs were located with GPS and received different management treatments. Some were manually removed with shovels, some were treated with a glyphosate Roundup Max 5 % formula on the leafs, others were cut and paint with glyphosate or with a saturated salt solution as an environmentally friendly alternative. The direct effect of these treatments in terms of kill rate and vital regrowth will be compared so that a clear advice can be given to the manager of these areas. Besides this field trial, which targets individual plants and small infestations in sensitive areas, a demonstration was held (November 2013) in highly infested areas on mechanical removal using a heavy excavator. Here, invasive shrub (Oregon grape Mahonia aquifolium and Japanese rose Rosa rugosa) removal was combined with large scale landscape restoration. The effort will be documented (cost, effort, aftercare) and the outcome monitored in terms of regrowth from different depths. This work is performed in cooperation with the Agency for Nature and Forest (ANB). The trials and demonstrations are performed within the framework of the EU co-funded Interreg 2Seas project RINSE (Reducing the Impact of Non-Native Species in Europe) (www.rinse-europe.eu) (2012-2014), which seeks to improve awareness of the threats posed by INNS, and the methods to address them. RINSE also engaged in networking with local stakeholder forums to set up preventive actions towards garden centers, public bodies and private owners. The first comprehensive results of the Mahonia field trial are expected in spring 2014.

As the eel is a long-lived, carnivorous, benthic and lipid-rich species, it is particularly prone to the accumulation of noxious chemical compounds, especially lipophilic contaminants like polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and brominated flame retardants (BFRs). At the Research Institute for Nature and Forest (INBO), a monitoring network was set up to measure contaminants in the eel over Flanders during a 15-year research programme, starting from 1994. More than 3000 eels from 376 locations were analysed for PCBs, OCPs, heavy metals and some other compounds.The data showed clearly that eels in their yellow stage are excellent chemical bioindicators; contaminant profiles in the studied eels are fingerprints of the contamination pressure on the site where they grow up.Results generated status reports and distribution maps of eel pollution for some 30 substances. Most substances are present all over Flanders, but there is considerable variation between river basins, dependent on land use. Contaminant analysis in eel is able to pinpoint specific pollution sources, like some volatile organic compounds in very specific locations, very high BFR levels in eels from areas with intensive textile industry, or high lindane levels in some rivers under agricultural pressure. We could demonstrate that banned chemicals like DDT are still in use in some places. Within the study period, trend analysis indicated significant reductions in PCBs and many OCPs. Also for some heavy metals (lead, arsenic, nickel and chromium), concentrations decreased in the eel, but this was not the case for cadmium and mercury.Self-caught eels are much esteemed by fishermen, but considering the eel’s high contaminant body burden, consumption constitutes a potential risk for human health. On many sites levels of specific compounds exceed legal maximum levels.Several contaminants were assessed for their potential impact on the eel population. Contaminants may impact on various levels of biological organisation from molecular, individual to population and community, hence the nature of the effects varies to a very wide extent. Despite a very high internal load of endocrine disrupters, we did not find any effects on vitellogenin levels in immature yellow eel. However, a significant negative correlation between heavy metal pollution load and condition was observed, suggesting an impact of pollution on the health of sub-adult eels. In strongly polluted eels a reduced genetic variability was observed. New advances in gene expression profiling, using either microarrays or RNA-seq, offers the opportunity to investigate the effects of pollutants at the genome-wide level and also showed significant impacts.It was further demonstrated that fat stores and condition decreased significantly during the last 15 years in eels in Flanders and The Netherlands, jeopardizing a normal migration and successful reproduction of this long-distance migrator. Belpaire et al (2009) hypothesized that pollution is a major driver for this decrease in fat reserves.Part of the work presented here has been summarized in two reviews. Geeraerts and Belpaire (2010) reviewed the potential effects of contamination on the eel and Belpaire et al. (2016) presented a simplified concept describing how reprotoxic chemicals may influence the status of the stock of the European eel.Belpaire C.G.J., G. Goemans, C. Geeraerts, P. Quataert, K. Parmentier, P. Hagel and J. De Boer. 2009. Decreasing eel stocks: Survival of the fattest? Ecol. Freshw. Fish. 18(2):197-214.Belpaire, C., Pujolar, J.M., Geeraerts, C., and Maes, G., 2016. Contaminants in Eels and their Role in the Collapse of the Eel Stocks. in press. In Biology and Ecology of Anguillid Eels T. Arai (Ed.)Geeraerts, C. and C. Belpaire. 2010. The effects of contaminants in European eel: a review. Ecotoxicology (2010) 19: 239–266

The Planning Group on the Monitoring of Eel Quality met at the Research Institute Nature and Forest (INBO) Brussels, Belgium, on the 20–22 January 2015 during its first Workshop (WKPGMEQ) under the subject “Development of standardised and harmonised protocols for the estimation of eel quality”, chaired by Claude Belpaire (Belgium) and Olga Haenen (The Netherlands). There were 31 participants (21 attendees and 10 remote participants) representing 13 countries.Reliable assessment of the eel stock quality and its quantitative effect on the reproductive stock is currently not possible, due to insufficient spatial and temporal data coverage (ICES 2009). This has emphasised the urgent need to establish a comprehensive overview with improved spatial coverage of the quality of the eel population across Europe as an essential and urgent requirement. Understanding the reproductive potential of the international spawning stock is a key component to predicting the effects on stock recovery of changes to silver eel escapement, arising from management actions implemented within Eel Management Plans.To address this need, ICES 2012 recommended that Member States implement routine monitoring of lipid levels, contamination and diseases. Many countries have started compiling data on the health status of eels in their water bodies. Objectives for these monitoring actions are diverse and are not restricted to the framework of eel recovery. Eel quality is also monitored for different purposes, which include human health considerations and to meet requirements of the Water Framework Directive. Hence, there is a large amount of information collected by EU member countries. However, procedures with respect to sampling, analysis and reporting are not harmonised, hindering stock wide assessments and risking inefficient use of resources. Consequently, ICES (2009) identified the need to develop standardised and harmonised protocols for the estimation of eel quality, so that national data would be comparable between Member States and could be reliably incorporated in international stock assessments.The objective of WKPGMEQ was to document standardised and harmonised protocols for the estimation of the quality of the European eel Anguilla anguilla, with regard to the bioaccumulation of contaminants and the presence of diseases, including parasites.WKPGMEQ took advantage of the preparative work of the participants who in advance of the workshop drafted reports describing the framework and methods used in their countries for the assessment of contaminants and diseases in the eel. At the start of the meeting Member States’ country reports were presented. Two subgroups, covering contaminants and diseases respectively, further discussed the practical issues surrounding the sampling, assessment procedures, diagnostic approaches and reporting related to measuring contaminants and diagnosis of eel parasites and other diseases. As far as possible, common procedures and guidelines were described.The report starts with an overview of the current eel quality assessments in the Member States, and further discusses general issues on sampling of eel quality assessments. It includes a chapter on the assessment of eel condition in terms of fitness and lipid levels. In further chapters best practices to (sub)sample, analyse, report and visualize contaminants in the eel are described. The disease sections focus on parasitic diseases (including the swimbladder parasite Anguillicoloides), and on viral and bacterial diseases. Possible ways to integrate data and to implement them into eel quality indices have been suggested. The workshop also discussed the future perspectives of using biomarkers of effects to assess eel health. Finally the report concludes describing the international context and future perspectives in eel health assessments.Several recommendations were made to facilitate the further development of a framework to integrate eel quality assessments into the quantitative management of the eel stock. Member States should apply harmonised methods for eel quality assessments and reporting, and routine monitoring and reporting of lipid levels, contamination and diseases needs to be integrated in the requirements within the Eel Regulation. Raw data should be made available to the international community and the management of the Eel Quality Database needs a structural basis. There is an urgent need for an internationally coordinated research project aiming at improving the understanding and quantification of the effects of contaminants on the reproductive success of the European eel, to allow integration of quality indicators in stock wide assessments.ICES, 2009. Report of the 2009 Session of the Joint EIFAC/ICES Working Group on Eels, FAO European Inland Fisheries Advisory Commission; International Council for the Exploration of the Sea, Göteborg, 7–12 September 2009, EIFAC Occasional Paper No. 45, ICES CM 2009/ACOM: 15. Rome, FAO/Copenhagen, ICES. 2010. p. 540 (Online).ICES, 2012. Report of the 2012 Session of the Joint EIFAAC/ICES Working Group on Eels, Copenhagen, Denmark, 3–9 September 2012; ICES CM 2012/ACOM:18, EIFAAC Occasional Paper 49, 828 pp.ICES, 2015. Report of the Workshop of a Planning Group on the Monitoring of Eel Quality under the subject “Development of standardized and harmonized protocols for the estimation of eel quality” (WKPGMEQ), 20–22 January 2015, Brussels, Belgium. ICES CM 2014/SSGEF:14. 274 pp.