Authors: Cacciatori, Cecilia; Tordoni, Enrico;Muter, Elżbieta;Czerepko, Janusz;Lech, Paweł ;

Cryptogamic diversity is a reliable indicator of the state of forest ecosystems. We analysed the variations in bryophyte alpha and beta diversity of central European managed forests over a 20-year time span, based on data collected in 132 plots scattered across Poland, and related them to changes in climatic conditions. We tested differences in species among sites grouped based on elevation a.s.l., dominant tree species and stand age. Species richness exhibited no significant trend across years, while it significantly increased along with elevation a.s.l., especially in broadleaved forests. Species richness exhibited a slight, but not significant increase over time in broadleaved forests, no variations in pine dominated stands and significant fluctuations in spruce dominated stands. Number of hemerophobic and strongly hemerophobic species underwent no significant variations across years either. Species turnover remained quite constant, despite a drop being observed between 2008 and 2013. These results show that bryophyte flora of central European managed forests has remained quite stable over the last two decades. This is related to the fact that, despite the general temperature increase, climatic patterns are not consistent across Poland, whose southern part has undergone a rainfall decrease, while its northern part exhibits a slight rainfall increase.