Technical FocusBig data integration: Pan-European fungal species observations' assembly for addressing contemporary questions in ecology and global change biology

•We outline a fungal meta-database for macroecology, biogeography and global change.•This meta-database integrates open-source data to exemplify integrative research.•Climate change effects on fungal phenology and fruiting patterns are exemplified.

Species occurrence observations are increasingly available for scientific analyses through citizen science projects and digitization of museum records, representing a largely untapped ecological resource. When combined with open-source data, there is unparalleled potential for understanding many aspects of the ecology and biogeography of organisms. Here we describe the process of assembling a pan-European mycological meta-database (ClimFun) and integrating it with open-source data to advance the fields of macroecology and biogeography against a backdrop of global change. Initially 7.3 million unique fungal species fruit body records, spanning nine countries, were processed and assembled into 6 million records of more than 10,000 species. This is an extraordinary amount of fungal data to address macro-ecological questions. We provide two examples of fungal species with different life histories, one ectomycorrhizal and one wood decaying, to demonstrate how such continental-scale meta-databases can offer unique insights into climate change effects on fungal phenology and fruiting patterns in recent decades.