Earlier research has suggested that the diversification of silvicultural strategies is a cost-efficient tool to ensure multifunctionality in production forests. This study compared the effects of continuous cover forestry and conventional rotation forestry on ecosystem services and biodiversity in boreal forests in Finland. We simulated over 25,000 commercial forest stands for 100 years under continuous cover and rotation forest management. Forests without management were used as a reference. We compared the effects of silvicultural practices over space and time on ecosystem services, biodiversity indicators and multifunctionality. Our results revealed that continuous cover forestry was better than rotation forest management in terms of timber net present value, carbon sequestration, bilberry production, scenic beauty and the number of large trees. It provided higher habitat availability for indicator species dependent on deciduous trees and mature forest structure. Rotation forest management was better than continuous cover forestry in terms of harvested tree biomass, cowberries, mushrooms, and species dependent on high tree volume. In general, multifunctionality was higher in continuous cover forests than in rotation forest. Therefore, continuous cover forests may have a greater potential to produce simultaneously multiple benefits from forests. However, unmanaged forests often provided the highest levels of services and biodiversity making their role indispensable in delivering forest related ecosystem services and, especially, in the maintenance of biodiversity. Continuous cover forestry does not itself guarantee the maintenance of all ecosystem services and biodiversity in commercial forests but it can be an important part of a successful progression towards more sustainable forestry.

Animals can avoid prédation by masquerading as objects that are not food to their predators. Alder moth Acronicta alni larvae go through an impressive ontogenetic change from masquerade to highly conspicuous appearance: early larval stages resemble bird droppings but in the last instar the larval coloration changes into striking yellow-and-black stripes. We hypothesized that such a change may be driven by differential prédation favoring dissimilar anti-predator strategies in different life stages. We show with a series of laboratory assays that larvae are distasteful to birds regardless of their developmental stage, suggesting that ontogenetic color change is not driven by the differential chemical defense. Birds showed higher variance in hesitation toward conspicuous prey; some individuals hesitated long time before attacking whereas all birds attacked instantly masqueraded prey. We also found that the activity level of the larvae increased with age, which fits to the fact that larvae need to move from foliage to pupation sites. In the field by using artificial larvae resembling the two life-history stages we found prédation risk to vary during the season: In early summer larger yellow-and-black larvae were attacked most, whereas later in the summer small ‘bird-dropping-larvae’ suffered the highest prédation. We conclude that the ontogenetic switch from masquerading to aposema-tism is adaptive most likely because actively moving prey cannot mimic immotile objects and thus, aposematism during the active and vulnerable period when larvae are searching for pupation sites becomes beneficial.

Riparian forests have cool and humid microclimates, and one aim of leaving forested buffer strips between clear-cut areas and streams is to conserve these microclimatic conditions. We used an experimental study set up of 35 streamside sites to study the impacts of buffer strip width (15 or 30 meters) and selective logging within the buffer strips on summer-time air temperature, relative air humidity and canopy openness 12 years after logging. The buffer strip treatments were compared to unlogged control sites. We found that 15-meter buffer strips with or without selective logging and 30-meter buffer strips with selective logging were insufficient in maintaining temperature, relative humidity and canopy openness at similar levels than they were in control sites. In contrast, 30-meter buffer strips differed only little from control sites, but they did have significantly lower mean air humidity. Microclimatic changes were increased by southern or southwestern aspect of the clearcut, and by logging on the opposite side of the stream. We also tested how the cover of three indicator mosses (Hylocomium splendens, Pseudobryum cinclidioides and Polytrichum commune) had changed (from pre-logging to 12 years post-logging) in relation to post-logging air temperature, relative air humidity and canopy openness. We found that each of the species responded to at least one of these physical conditions. Air humidity was the most significant variable for explaining changes in the cover of the indicator moss species, suggesting that the changes in this microclimatic component has biological impacts. We conclude that to preserve riparian microclimatic conditions and species dependent on those, buffer strips should exceed 30 meters in width, and not be selectively logged. Wider buffer strips are required if the clear-cut is towards south or southwest, or if the two sides of the stream are logged at the same time or during subsequent years.

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