Do plant-based biogeographical regions shape aphyllophoroid fungal communities in Europe?

Aim: Aphyllophoroid fungi are associated with plants, either using plants as a resource (as parasites or decomposers) or as symbionts (as mycorrhizal partners). In spite of their strong association with plants, it is unknown how much plant distributions determine their biogeographical patterns compared with environmental factors such as climate and human land use. In this study, our aims are to (1) describe the spatial diversity patterns of aphyllophoroid fungi in Europe and (2) identify the factors shaping these patterns. Location: Europe, as well as the adjacent Subarctic to Arctic islands (Greenland, Faroe Islands, Iceland, Svalbard), Palestine and the south-east coast of the Caspian Sea. Methods: We compiled a dataset consisting of 14,030 fruitbody occurrences of 1,491 aphyllophoroid fungal species from 39 geographical areas (17 countries) belonging to eight biogeographical regions. We assessed the differences in fungal species richness and overall diversity and its nestedness and turnover components across biogeographical regions of Europe, as well as between southern and northern Europe (based on geographical latitude of 50 degrees as threshold). We used cluster and ordination analyses to classify the European aphyllophoroid communities biogeographically and evaluated the importance of climate, host-tree species, topography and human land-use intensity in explaining biogeographical variation. Results: The importance of biogeographical regions in determining European aphyllophoroid fungal communities varies for different diversity components. Species richness and nestedness are best explained by plant-based biogeographical regions, whereas overall beta diversity and species turnover are driven mostly by variation in climate, and nestedness mostly by tree species occupancy. Beta-diversity patterns of aphyllophoroid fungi do not differ between southern and northern Europe. Main conclusions: At the continental scale, aphyllophoroid fungi are less shaped by historical legacies than vascular plant and animal communities, and trends of overall beta diversity in southern and northern Europe are similar to patterns found for bryophytes.Peer reviewe