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Research article - Peer-reviewed, 2022

Bryophytes of conservation concern decline and traits change in retention patches during two decades following forest harvest

Jonsson, Mari; Perhans, Karin; Appelgren, Leif; Gustafsson, Lena


Setting aside tree retention patches at final harvest is a common forest conservation measure, but the long-term responses of species of conservation concern to different types of forest retention remain unknown. This is the first long-term study of the dynamics of bryophytes of conservation concern and associated traits in small forest retention patches (0.01-0.53 ha) over almost two decades and in relation to environmental drivers. We applied joint species distribution models to compare how bryophytes changed in terms of occurrence, abundance, species richness and traits between year 2000, 2006 and 2018, and in relation to five different retention patch types, patch area, retained living tree volume per hectare, structural heterogeneity, and surrounding habitat openness. Bryophytes responded mostly negatively to the long-term environmental change, although with considerable variation depending on retention patch type. Only negative trends were detected for individual species. Still, no regional extinctions (loss of species from all local patches) occurred and there was a tendency for recovery of a few species. Bryophytes with predominantly asexual reproductive modes and small colony size (< 100 cm(2)) increased in occurrence probability over time, indicating that these traits were beneficial for the long-term persistence of species in small and exposed forest patches. We recommend forest managers to create large (preferably up to 0.5 ha) and variable retention patches, both in terms of patch type (i.e. buffer zones and free-standing groups of different dominant tree species and ground moisture) and structural heterogeneity (i.e. living tree volumes, large and small trees, and deadwood).


Biodiversity; Edge effects; Forest fragmentation; Forest management; Functional traits; Green tree retention

Published in

Biological Conservation
2022, Volume: 273, article number: 109647