Fungal sporocarp productivity and diversity shaped by weather conditions in Pinus uncinata stands

Pinus uncinata is a species frequently growing in the tree line limit of southwestern European subalpine ecosystems, hosting fungal communities that provide relevant ecosystem services. Despite the high importance of these forests for conservation, limited prior research has analysed the sporocarp fruiting patterns. This study aims at filling this gap in knowledge by describing interannual changes in sporocarp productivity, diversity, and community composition over 5 years and identifying possible relationships with the main weather and soil physicochemical characteristics. The studied P. uncinata stands had an average annual total sporocarp productivity of 21.60 kg ha-1yr−1 in dry weight, hosting a total of 255 species with productivity-dominant ectomycorrhizal families such as Russulaceae and Tricholomataceae that occurred mostly from mid-August to end September. In contrast, saprotrophs showed more stable productivity values from mid-August to end of November with average annual sporocarp productivity of 1.76 kg ha-1yr−1 in dry weight but exhibited higher fungal richness values from the start of October until the end of November. Fungal productivity and species richness were mostly influenced by weather conditions while soil physicochemical properties had implications in shaping the sporocarp community composition. This study quantifies the interannual fungal fruiting pattern of the understudied fungal communities and underlines the importance of climatic variables in shaping fungal fruiting patterns within a climate change context. In addition, this work is also of special relevance since P. uncinata ecosystems represent the tree line limit, which makes this species and its associated fungal communities especially sensitive to the potential impacts of global warming.

This work was supported by the Secretariat for Universities and of the Ministry of Business and Knowledge of the Government of Catalonia and the European Social Fund and the Spanish Ministry of Science, Innovation and Universities, grant RTI2018-099315-A-I00. In addition, this work was partially supported by the project PCI2022-135091-2 (MicroEco project - call Biodiversa + 2021), funded by MCIN/AEI/10.13039/501100011033 and for the European Union “NextGenerationEU”/PRTR”, and by the National Parks Autonomous Agency (Organismo Autónomo de Parques Nacionales, OAPN) (Grant No. 2711/2021). Josu G. Alday was supported by Ramon y Cajal fellowship (RYC-2016-20528). José Antonio Bonet and Sergio de Miguel benefitted from a Serra-Húnter Fellowship provided by Generalitat de Catalunya.