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The use of large clearcuts with protection of advance regeneration is inappropriate for regeneration of balsam fir (Abies balsamea (L.) Mill.) under severe browsing from white-tailed deer (Odocoileus virginianus (Zimmermann)). However, little is known about the effects of tree-retention methods along with scarification on the establishment of balsam fir in a context of severe herbivory. Consequently, we hypothesized that seed-tree-group cutting in conjunction with soil scarification creates favourable conditions for balsam fir regeneration. In 1998 and 1999 we set up three circular forest groups of different sizes (40, 60, and 80 m in diameter) surrounded by three different intensities of scarification (no treatment, single pass, double pass) in two balsam fir stands on Anticosti Island, Quebec, Canada. Moreover, we used a network of fenced and unfenced regeneration plots to evaluate the impact of white-tailed deer browsing. The results showed that up to 7 years after harvest, seed-tree-group cutting did not improve the establishment of conifer species. Scarification had a negative impact on the abundance of conifer species, whereas white birch (Betula papyrifera Marshall) density was significantly higher in areas scarified twice than in unscarified areas. Overall, the development of palatable tree species appears unlikely at deer densities >20 individuals/km2., L’utilisation de grandes coupes à blanc avec protection de la régénération s’est avérée inefficace pour régénérer le sapin baumier (Abies balsamea (L.) Mill.) en présence de densités élevées de cerf de Virginie (Odocoileus virginianus (Zimmermann)). Cependant, peu d’études ont évalué l’efficacité de coupes avec rétention d’arbres, jumelées avec une préparation de terrain, pour favoriser l’établissement de la régénération soumise à un fort broutement. Nous avons donc testé l’effet d’une coupe avec réserve d’îlots semenciers, jumelée avec différentes intensités de scarifiage, pour améliorer les conditions d’établissement du sapin baumier. En 1998 et 1999, nous avons installé des îlots semenciers de 40, 60 et 80 m de diamètre autour desquels nous avons effectué trois intensités de scarifiage (aucun traitement, un passage et deux passages) dans deux sapinières sur l’île d’Anticosti (Québec, Canada). De plus, nous avons installé un réseau de parcelles clôturées et non clôturées pour évaluer l’effet du broutement. Sept ans après la coupe, les résultats montrent que la réserve d’îlots semenciers et le scarifiage n’ont pas amélioré l’établissement des conifères. Le scarifiage a néanmoins permis d’augmenter significativement la densité de bouleau à papier (Betula papyrifera Marshall). Toutefois, le développement des essences consommées par le cerf apparaît compromis à des densités locales >20 individus/km².

Understanding how large herbivores shape plant diversity patterns is an important challenge in community ecology, especially because many ungulate populations in the northern hemisphere have recently expanded. Because species within plant communities can exhibit strong interactions (e.g., competition, facilitation), selective foraging by large herbivores is likely not only to affect the abundance of palatable species, but also to induce cascading effects across entire plant communities. To investigate these possibilities, we first tested the effects of deer browsing and soil disturbance on herbaceous plant diversity patterns in boreal forest, using standard analyses of variance. Second, we evaluated direct and indirect effects of deer browsing and soil disturbance on the small-scale richness of herbaceous taxa using a multilevel path analysis approach. The first set of analyses showed that deer browsing and soil disturbance influenced herb richness. Path analyses revealed that deer browsing and soil disturbance influenced richness via complex chains of interactions, involving dominant (i.e., the most abundant) browsing-tolerant (DBT) taxa and white birch (Betula papyrifera), a species highly preferred by white-tailed deer (Odocoileus virginianus). We found no evidence that an increase of white birch in fenced quadrats was the direct cause of a decrease in herb richness. However, we found strong evidence that a higher abundance of DBT taxa (i.e., graminoids and Circium arvense), both in fenced and unfenced quadrats, increased herb layer richness. We propose an empirical model in which competitive interactions between white birch and DBT taxa regulate the strength of facilitative relationships between the abundance of DBT taxa and herb richness. In this model, deer browsing and the intensity of soil disturbance initiate a complex chain of cascading effects in boreal plant communities by controlling the abundance of white birch.

Heavy browsing pressure from large ungulates is a multicontinent phenomenon that causes regeneration failure of many palatable tree species and induces important socioeconomic and ecological impacts in forest ecosystems. The development of forest management practices that address adequately this issue, however, remains scarce and challenging because (1) large herbivores are both a resource and a source of disturbance; (2) the management of forests and ungulate populations remains largely disconnected in practice; and (3) we still lack a good understanding of the role of critical factors, especially deer densities, vegetation attributes, and their interactions, on the magnitude of browsing damages on forest regeneration. We bring new insights into these challenging issues by critically reviewing the current methods used by managers and conservationists to mitigate deer impacts on forest regeneration, emphasizing the spatial scale at which these methods are undertaken. Specifically, we review management actions at multiple scales on both deer populations (e.g., hunting) and vegetation (e.g., silvicultural treatments) that are common to most deer–forest systems and, for that reason, deserve priority investigation. We identify strengths and limitations of current management actions and highlight the main research gaps. Based on this review, we propose a new integrated management scheme that explicitly addresses: (1) the integration and prioritization of management actions, (2) the development of adaptive management plans, and (3) the participation of stakeholders. Conflicting demands by different stakeholders have challenged the effectiveness of management strategies in deer–forest systems. To reverse this situation, we advocate for a shift of paradigm and the development of integrated strategies that (1) bridge the gap between management actions and the design of in situ experiments and (2) coordinate actions at multiple spatial scales on both deer populations and fore

At the northernmost extent of the managed forest in Quebec, Canada, the boreal forest is currently undergoing an ecological transition between two forest ecosystems. Open lichen woodlands (LW) are spreading southward at the expense of more productive closed-canopy black spruce-moss forests (MF). The objective of this study was to investigate whether soil properties could distinguish MF from LW in the transition zone where both ecosystem types coexist. This study brings out clear evidence that differences in vegetation cover can lead to significant variations in soil physical and geochemical properties. Here, we showed that soil carbon, exchangeable cations, and iron and aluminium crystallinity vary between boreal closed-canopy forests and open lichen woodlands, likely attributed to variations in soil microclimatic conditions. All the soils studied were typical podzolic soil profiles evolved from glacial till deposits that shared a similar texture of the C layer. However, soil humus and the B layer varied in thickness and chemistry between the two forest ecosystems at the pedon scale. Multivariate analyses of variance were used to evaluate how soil properties could help distinguish the two types at the site scale. MF humus (FH horizons horizons composing the O layer) showed significantly higher concentrations of organic carbon and nitrogen and of the main exchangeable base cations (Ca, Mg) than LW soils. The B horizon of LW sites held higher concentrations of total Al and Fe oxides and particularly greater concentrations of inorganic amorphous Fe oxides than MF mineral soils, while showing a thinner B layer. Overall, our results show that MF store three times more organic carbon in their soils (B+FH horizons, roots apart) than LW. We suggest that variations in soil properties between MF and LW are linked to a cascade of events involving the impacts of natural disturbances such as wildfires on forest regeneration that determines the vegetation structure (stand density

Heavy browsing pressure from large ungulates is a multicontinent phenomenon that causes regeneration failure of many palatable tree species and induces important socioeconomic and ecological impacts in forest ecosystems. The development of forest management practices that address adequately this issue, however, remains scarce and challenging because (1) large herbivores are both a resource and a source of disturbance; (2) the management of forests and ungulate populations remains largely disconnected in practice; and (3) we still lack a good understanding of the role of critical factors, especially deer densities, vegetation attributes, and their interactions, on the magnitude of browsing damages on forest regeneration. We bring new insights into these challenging issues by critically reviewing the current methods used by managers and conservationists to mitigate deer impacts on forest regeneration, emphasizing the spatial scale at which these methods are undertaken. Specifically, we review management actions at multiple scales on both deer populations (e.g., hunting) and vegetation (e.g., silvicultural treatments) that are common to most deer–forest systems and, for that reason, deserve priority investigation. We identify strengths and limitations of current management actions and highlight the main research gaps. Based on this review, we propose a new integrated management scheme that explicitly addresses: (1) the integration and prioritization of management actions, (2) the development of adaptive management plans, and (3) the participation of stakeholders. Conflicting demands by different stakeholders have challenged the effectiveness of management strategies in deer–forest systems. To reverse this situation, we advocate for a shift of paradigm and the development of integrated strategies that (1) bridge the gap between management actions and the design of in situ experiments and (2) coordinate actions at multiple spatial scales on both deer populations and fore