Macroclimate modulates the positive dead-wood influence on bryophyte diversity in managed and unmanaged temperate lowland forests.

Extending the network of strict forest reserves is one of the conservation measures promoted by the French National Strategy for Biodiversity. However, there is a lack of evidence concerning the efficiency of setting aside strict forest reserves to preserve biodiversity in the case of temperate forests. Moreover, there are potentially unexplored underlying ecological mechanisms that forest management could usefully mimic. In order to disentangle the respective roles of management abandonment, stand structural attributes and climatic and topographic variables in determining forest biodiversity, we conducted the first national-scale study in France comparing biodiversity in managed and in unmanaged forests. Here we focus on bryophytes (all species combined and forest specialists separately). We analyzed data from 127 plots in ten lowland forests in France. Our aim was to disentangle the relationships between bryophyte richness and (i) management abandonment per se, (ii) associated forest-structure variables like deadwood volume, and (iii) macroclimatic variables important for bryophytes (temperature, precipitation, relative humidity, solar radiation and vapor pressure deficit). For each studied combination of variables (univariate, additive or interactive models), we compared hierarchical models of several types: linear with a fixed slope, linear with a random slope, quadratic, sigmoid or threshold models. We found that deadwood variables were the main drivers of bryophyte richness in managed as well as in unmanaged stands. We observed a sigmoid relationship of total deadwood volume to overall richness, and a threshold effect of large and very large deadwood volume on forest specialist richness. The effect of management abandonment was globally non-significant, though impact varied strongly among the different forest sites. A combination of deadwood and macroclimatic variables best predicted bryophyte richness, through non-linear relationships: 1) higher solar radiation reinforced the positive effects of large deadwood on forest-specialist bryophyte richness; and 2) higher mean annual temperatures counteracted the positive effects of total deadwood amount on total bryophyte species richness. Maintaining high amounts of deadwood in both managed and unmanaged forests is likely to improve bryophyte richness and will be particularly important under ongoing climate change.

Can nature conservation and wood production be reconciled in managed forests? A review of driving factors for integrated forest management in Europe.

Integrated forest management (IFM) can help reconcile critical trade-offs between goals in forest management, such as nature conservation and biomass production. The challenge of IFM is dealing with these trade-offs at the level of practical forest management, such as striving for compromises between biomass extraction and habitat retention. This paper reviews some of the driving factors that influence the integration of nature conservation into forest management. The review was conducted in three steps - a literature review, an expert workshop and an expert-based cooperative analysis. Of 38 driving factors identified, three were prioritised by more of the participants than any of the others: two are socio-cultural factors, identity (how people identify with forest) as well as outreach and education, and one is economic - competitiveness in forest value chains. These driving factors correspond to what are considered in the literature as enablers for IFM. The results reveal that targeted, group-oriented, adaptive and innovative policy designs are needed to integrate nature conservation into forest management. Further, the results reveal that a "one-size-fits-all" governance approach would be ineffective, implying that policy instruments need to consider contextually specific driving factors. Understanding the main driving factors and their overall directions can help to better manage trade-offs between biodiversity conservation and biomass production in European forests.