Temperate forests of northeastern North America provide key ecosystem services but are increasingly affected by multiple stressors, including climate change, biological invasions, pollution, and land-use impacts, potentially altering species composition and thus productivity and sustainability of these forests. This study examined 20-year compositional changes in 233 uneven-aged forest stands subjected to single-tree selection (STS) cutting or left unmanaged, encompassing hardwood and mixedwood stands across southern Quebec, Canada. Analyses were based on species-specific proportions of basal area across three developmental stages: saplings, recruit trees, and pre-existing canopy trees. Results indicated that compositional shifts primarily occurred in younger cohorts (saplings and recruits), while canopy composition remained relatively stable. In hardwood stands, the proportion of sugar maple (Acer saccharum Marsh.) declined among recruits and saplings, whereas that of American beech (Fagus grandifolia Ehrh.) increased, indicating a gradual replacement dynamic. Yellow birch (Betula alleghaniensis Britt.), a mid-tolerant species, remained underrepresented in these stages, though it was promoted by STS compared with the unmanaged control. In mixedwood stands, yellow birch dominated the canopy, but balsam fir (Abies balsamea (L.) Mill.) became prevalent among recruits and saplings. These trends were observed in both STS and control plots, suggesting that harvest operations had marginal impact on forest composition. Rather, some broader ecological drivers, beyond silvicultural practices alone, were likely more influential. Our results point toward an impending shift in species dominance, particularly in hardwood stands. Adaptive silvicultural strategies, combined with consideration of emerging biotic stressors, will be essential to sustain desired species composition and associated ecosystem services.
Loss and intensified management of meadows, grasslands and open woodlands have caused widespread declines of butterflies in Europe. While historical forests contained dispersed open habitats as a result of windfall, wetlands, and large herbivores, many forests today are more closed and less structurally diverse through most of the forest cycle. However, temporary open habitat created by clear-cuts under rotational forestry may be used by butterflies, with their use potentially depending on connections to more permanent open habitats. In Sweden, where more than half of the land area consists of production forest with few naturally open areas, clear-cuts are ubiquitous and can provide habitat for species associated with open habitats and forest edges. We compared butterfly communities at the centre of 120 forest clear-cuts in two different Swedish regions, one with a forest-dominated landscape with little grass- and farmland (Dalarna), and one with a forest-farmland mosaic landscape (Scania). The main objective was to evaluate how butterfly use of transient, open clear-cut habitat depends on successional stage and landscape context. We combined the survey of 120 clear-cuts in 2018, 2019 and 2020 with landscape analyses. We used (i) a dbRDA to understand the drivers of community structure; (ii) GLMs to investigate the landscape and local drivers of farmland and grassland butterfly indicators; and (iii) joint species distribution models to understand how traits and phylogeny mediate species’ responses to local and landscape variables. All 14 species of the Swedish farmland indicator, and 9 out of the 12 grassland indicator species, were observed in the 120 surveyed clear-cuts. The butterfly communities differed markedly between the regions, but also with respect to the area of clear-cuts and farmland in the surrounding landscape. Most importantly, clear-cuts were used by many grassland and farmland butterfly species, with their occurrence and abundance associated with the composition of the surrounding landscape. This indicates that clear-cuts may provide functional habitats for some butterfly species, depending on their ecological requirements and the broader landscape context. Body size and larval host-plant type partly explained butterfly species distributions in clear-cuts. Our results demonstrated that use of clear-cuts is filtered by life-history traits, with the proportion of roads also associated with the occurrence of several species, highlighting the role that landscape-wide management could play for butterfly conservation even in production forests. Hence, while clear-cuts are known to have negative consequences for forest biodiversity, we show that their ubiquitous use in modern forestry could have positive incidental consequences for butterflies, with these effects depending on the broader landscape context.
Fire is a key disturbance in forests around the globe. Fire shapes the structure in forests that provide essential habitat for wildlife. The post fire recovery of forests have often been characterised as a function of time since fire, overlooking the influence of additional fire characteristics, and post-fire environmental conditions. This knowledge is vital to support wildlife conservation under rapidly changing fire regimes arising from climatic extremes. In this study, we model the effects of fire severity, minimum fire intervals, and environmental context on the trajectory of wildlife habitat using structural data from 401 sclerophyll forest sites across 29 wildfires. Fire variables were included in the best supported models for all but graminoid cover. Fire severity strongly influenced post-fire trajectories of shrub cover, basal area of dead trees, tree density, and canopy cover. Within the top models, time since fire independently shaped four structures, with litter depth and shrub cover associated with positive recovery, while canopy cover and basal area of dead trees exhibited non-linear declines. However, most habitat structures were best explained by two- and three-way interactions among time since fire, fire regime attributes, and environmental conditions, highlighting the complexity of recovery dynamics in these forests. These findings demonstrate that time since fire alone is insufficient to model forest recovery and suggest that management decisions based on fire characteristics and environmental gradients will support more practical conservation actions.
