Résumé - CAFD


Boreal bryophyte response to natural fire edge creation.

Marion Barbé, Nicole J. Fenton, Yves Bergeron.

Question

Changes in species richness and composition in plant communities as a result of edge creation are well documented in anthropogenically modified landscapes, but what happens after natural disturbance? We investigate the responses of boreal bryophytes to edge creation in a post-wildfire residual forest patch system.

Location

Boreal black spruce–feather moss forest, western Québec, Canada.

Methods

Bryophyte community was sampled in 50-m2 plots: 117 plots in 39 undisturbed forest cores (control) and 108 plots in 30 residual forest patches from wildfire, divided into 48 core plots, 30 north-facing edge plots and 30 south-facing edge plots. Temporal, severity, spatial and structural characteristics of the stands were also recorded to explain bryophyte community composition.

Results

Residual edges and cores were more species-rich than undisturbed cores, particularly north-facing edges, but community composition differed between undisturbed and residual cores. Indicator species of undisturbed cores and residual edges differed in their species traits. Spatial variables explained variations in composition, with a larger difference between core and edge communities in patches over 3 ha compared to smaller patches.

Conclusion

We observed community composition change in response to natural edge creation. While edge influence is reduced in large patches, the bryophyte community remains distinct from undisturbed cores. This community change is a ‘control’ in studies of boreal bryophyte response to anthropogenic edge creation, and suggests that we should consider the natural range of variability. Finally, this study emphasizes that forest remnants do not substitute for continuous and undisturbed forests.