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Genetic diversity influences the evolutionary potential of forest trees under changing environmental conditions, thus indirectly the ecosystem services that forests provide. European beech (Fagus sylvatica L.) is a dominant European forest tree species that increasingly suffers from climate change-related die-back. Here, we conducted a systematic literature review of neutral genetic diversity in European beech and created a meta-data set of expected heterozygosity (He) from all past studies providing nuclear microsatellite data. We propose a novel approach, based on population genetic theory and a min–max scaling to make past studies comparable. Using a new microsatellite data set with unprecedented geographic coverage and various re-sampling schemes to mimic common sampling biases, we show the potential and limitations of the scaling approach. The scaled meta-dataset reveals the expected trend of decreasing genetic diversity from glacial refugia across the species range and also supports the hypothesis that different lineages met and admixed north of the European mountain ranges. As a result, we present a map of genetic diversity across the range of European beech which could help to identify seed source populations harboring greater diversity and guide sampling strategies for future genome-wide and functional investigations of genetic variation. Our approach illustrates how to combine information from several nuclear microsatellite data sets to describe patterns of genetic diversity extending beyond the geographic scale or mean number of loci used in each individual study, and thus is a proof-of-concept for synthesizing knowledge from existing studies also in other species.

AGAP : équipe CONSYT; International audience; Whilst the benefits of agroforestry are widely recognised in tropical latitudes few studies have assessed how agroforestry is perceived in temperate latitudes. This study evaluates how stakeholders and key actors including farmers, landowners, agricultural advisors, researchers and environmentalists perceive the implementation and expansion of agroforestry in Europe. Meetings were held with 30 stakeholder groups covering different agroforestry systems in 2014 in eleven EU countries (Denmark, France, Germany, Greece, Hungary, Italy, Netherlands, Portugal, Spain, Sweden and the United Kingdom). In total 344 valid responses were received to a questionnaire where stakeholders were asked to rank the positive and negative aspects of implementing agroforestry in their region. Improved biodiversity and wildlife habitats, animal health and welfare, and landscape aesthetics were seen as the main positive aspects of agroforestry. By contrast, increased labour, complexity of work, management costs and administrative burden were seen as the most important negative aspects. Overall, improving the environmental value of agriculture was seen as the main benefit of agroforestry, whilst management and socio-economic issues were seen as the greatest barriers. The great variability in the opportunities and barriers of the systems suggests enhanced adoption of agroforestry across Europe will be most likely to occur with specific initiatives for each type of system.

Despite the economic importance of Theobroma cacao, surprisingly little is known about its pollination ecology. Ceratopogonid midges are considered to be the main pollinators, but the limited available evidence on the sexual reproduction is based almost exclusively on cultivated cacao and knowledge is nonexistent for wild populations. We documented flower visitors in wild and cultivated plants by applying glue on 2237 flowers of wild and cultivated cacao trees in Bolivia to trap floral visitors. We caught 631 insects belonging to seven orders, corresponding to a mean capture rate of 0.3 insects per flower. The most abundant and diverse insect order on both cacao types was Hymenoptera, represented mainly by small parasitoids. Hymenoptera were more abundant on wild cacao, whereas species richness was higher on cultivated cacao. The abundance and species richness of Diptera were not significantly different between wild and cultivated cacao. However, species composition and proportion of Diptera species differed between both wild and cultivated cacao. Ceratopogonidae were only represented by 13 individuals belonging to seven species. Cacao pollen was carried by only a single specimen of Encyrtidae. We were thus unable to identify actual pollinators. We found significant differences among the visitor assemblages between wild and cultivated cacao, which suggest that midges alone were probably too rare to act as main or even sole pollinators of cacao in our study region. Potential additional pollinators would be small Diptera (e.g., Chloropidae and Phoridae) and Hymenoptera (e.g., Eulophidae and Platygastridae).