Abstract Background In boreal zone forest management is changing and degrading forest habitats, which has caused declines in biodiversity. To mitigate these harmful effects in production forests, small-scale habitats with high biodiversity values have been protected within them. These habitats include woodland key habitats, and other small habitat patches protected by voluntary conservation actions. In this systematic review we synthesize the evidence on the value of small protected habitat patches (SPHP) within production forest landscapes for biodiversity. Review question: Are small protected habitat patches within boreal production forests effective in conserving species richness, abundance, and community composition? Methods Both peer-reviewed and grey literature were searched from bibliographical databases, organizational websites and internet search engines in English, Finnish, Swedish and Russian. Articles were screened at two stages (title/abstract and full text) and the validity of the included studies were assessed. Screening and validity assessment were based on predetermined criteria. After data extraction, narrative and quantitative syntheses were conducted. Influences of effect modifiers were tested, and sensitivity analyses were conducted. Review findings During the searches 19,458 articles were found. After duplicate removal and title/abstract screening 336 articles remained. During full text screening 41 articles were included and 35 of them (174 studies) were included in narrative synthesis. 28 articles with 127 studies had suitable data for meta-analysis. SPHPs had significantly higher species richness compared to production forests. When compared to natural forests, there was no significant difference. Forest management in areas surrounding SPHPs did not have impact on species richness of these patches. Individual abundance was significantly higher in SPHPs compared to natural or production forests. There was significantly more dead wood in SPHPs compared to production forests, but when compared to natural forests there was no significant difference. Community composition was different between SPHPs and both production and natural forests. Conclusions The findings of this review show that small protected patches within production forests are important part of biodiversity conservation. They cannot substitute larger protected areas but supplement the protected area network. However, there were gaps both in geographical distribution of the studies as well as in the selection of target species of the studies. Therefore, generalization of the results must be done carefully.

We examined the occurrence of carabid beetles along a forest succession gradient in central Finland (forest age classes: 5, 10, 20, 30 and 60 years since clear-cutting). Species richness of carabids was higher in the two youngest age classes, while no clear differences were detected in carabid abundance. The high species richness in the young, open sites was due to invasion of open-habitat species. Many forest species were absent from or scarce in the young sites and became gradually more abundant towards the older forest age classes. The catches indicated a drastic decrease and assemblagelevel change in concert with canopy closure, i.e. 20–30 years after clear-cutting. Some forest specialists with poor dispersal ability may face local extinction, if the proportion of mature forest decreases further and the remaining mature stands become more isolated. We recommend that, while harvesting timber, connectivity between mature stands is ensured, mature stands are maintained close (a few tens of metres) to each other and the matrix quality is improved for forest species by green tree retention.

Abstract Background Forest harvesting is the main driver of habitat degradation and biodiversity loss in forests of the boreal zone. To mitigate harmful effects, small-scale habitats with high biodiversity values have been protected within production forests. These include woodland key habitats, and other small-scale habitat patches protected by voluntary conservation action. This article describes a protocol for a systematic review to synthesize the value of small habitat patches left within production landscapes for biodiversity. The topic for this systematic review arose from a discussion with the Finnish forestry sector and was further defined in a stakeholder workshop. Research question: Do small protected habitat patches within production forests provide value for biodiversity conservation in boreal forests? Animal, plant and fungal diversities are addressed as well as the amount of deadwood within the habitat patches as proxy indicators for biodiversity. Methods The literature, both peer-reviewed and grey, will be searched from bibliographical databases, organizational websites and internet search engines in English, Finnish, Swedish and Russian. Article screening will be done at two stages (title/abstract and full-text). The validity of the studies included will be evaluated against validity criteria and studies will be categorized based on their risk of bias. To describe the findings a narrative synthesis will be conducted. If there is enough quantitative data retrieved from the studies, a meta-analysis will be conducted.

Intensive management of boreal forests impairs forest biodiversity and species of old-growth forest. Effective measures to support biodiversity require detection of locations valuable for conservation. We applied species distribution models (SDMs) to a species of mature forest, the northern goshawk (Accipiter gentilis, goshawk), that is often associated with hotspots of forest biodiversity. We located optimal sites for the goshawk on a landscape scale, assessed their state under intensified logging operations and identified characteristics of goshawks' nesting sites in boreal forests. Optimal sites for the goshawk covered only 3.4% of the boreal landscape and were mostly located outside protected areas, which highlights the importance of conservation actions in privately-owned forests. Furthermore, optimal sites for the goshawk and associated biodiversity were under threat. Half of them were logged to some extent and 10% were already lost or notably deteriorated due to logging shortly after 2015 for which our models were calibrated. Habitat suitability for the goshawk increased with increasing volume of Norway spruce (Picea abies) peaking at 220 m(3) ha(-1), and with small quantities of birches (Betula spp.) and other broad-leaved trees. Threats to biodiversity of mature spruce forests are likely to accelerate in the future with increasing logging pressures and shorter rotation periods. Logging should be directed less to forests with high biodiversity. Continuous supply of mature spruce forests in the landscape should be secured with a denser network of protected areas and measures that aid in sparing large entities of mature forest on privately-owned land.