Microclimatic conditions and forest structure influence bryophyte community composition and β-diversity

Bryophytes are key elements of the forest ecosystem. They are known to be sensitive to small changes in their environment and especially climate, yet forests display particular microclimatic conditions that differ from open-field climate. There is a lack of knowledge on which microclimate components affect bryophytes the most, as well as how vegetation structure impacts forest microclimate. While most stud-ies focus on larger scales, there is little knowledge about how bryophyte community composition and diversity change at a small scale inside a temperate forest ecosystem. We measured forest microclimate experienced by 54 bryophyte communities in the Bois Chamblard, a forest located on the shores of Lake Geneva in Switzerland. We also measured the vegetation structure using terrestrial laser scanning (TLS) and other ecological factors such as deadwood, to assess their effects on microclimate and bryophyte communities. Surprisingly, soil humidity had a limited effect on bryophytes compared to temperature, and the geographical distance between sites also had a low influence on community composition and β-diversity. On the other hand, we found that deadwood had an important impact on bryophyte diver-sity. We also found clear links between forest structure components and microclimate. Our study high-lights the importance of microclimate, and especially its temperature component, on bryophyte com-munities in a temperate forest ecosystem. We emphasize the importance of small changes in forest microclimate and the impact of vegetation structure to be carefully considered for bryophytes conser-vation when it comes to managing forests in a climate change context.