Impact of forest management on the diversity of corticolous bryophyte assemblages in temperate forests

Abstract

This study aimed at comparing the composition, the structure and the organisation of corticolous bryophyte assemblages (recorded within a 400 m 2 plot) between three silvicultural managements widely conducted in Europe: Even-Aged pure beech Forest (EAF), Coppice With Standards system (CWS) and Selective Cutting systems (SC). The stands used for the study were located in two neighbouring regions of northern France. Comparisons were performed using a functional approach based on species’ ecological requirements and life traits combined with multivariate analyses. Along the silvicultural cycle of the EAF, stand age and canopy opening were the main ecological factors influencing corticolous bryophyte assemblages. Old stands with a low canopy cover contained all the functional groups, with a preponderance of late successional and obligatory shade species. The regeneration stage appeared to be an outlier because of its lowest species richness. Although the same functional groups occurred in CWS and SC as in EAF, the bryophyte assemblages shared compositional and structural characteristics similar to those of EAF early and middle successional stages. This indicates that successional processes are not maintained by these management types and that the latter do not seem to favour late successional-obligatory shade species. EAF successional stages, CWS and SC did not exhibit differences in the relative species richness (i.e. the ratio between the number of species within the 400 m 2 plot (SR) and the richness of the local species pool) except for EAF regeneration stands. The results are used to propose practical ecological background information for the elaboration of forest management policies.