The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Yves Bergeron - One of the best experts on this subject based on the ideXlab platform.
-
importance of soil stand and mycorrhizal fungi in abies balsamea establishment in the Boreal Forest
Forests, 2020Co-Authors: Melissande Nagati, Yves Bergeron, Melanie Roy, Annie Desrochers, Monique GardesAbstract:Research highlights: To understand differences in the establishment of balsam fir regeneration observed in the Boreal Forest, we examined how soil layer and microorganisms explained differences in growth and mycorrhization in three different stand types. Our experiment revealed positive and negative effects on growth of seedlings, and highlights the importance of biotic interactions in balsam fir establishment. Background and Objectives: In a context of climate change, understanding tree migration can be examined through changes in tree regeneration. At the ecotone between mixed and conifer Boreal Forest, regeneration of balsam fir northward is of particular interest because it thrives better under aspen-dominated stands as compared to adjacent spruce-dominated stands. As the understorey differs between these stands, with more Ericaceae under spruce and different ectomycorrhizal fungal communities in organic and mineral horizons, we hypothesized that biotic factors could explain differences in balsam fir establishment. Materials and Methods: Using a growth chamber experiment, we tested if differences in soil layers and modification of soil fungal communities would affect germination, mycorrhization, and growth of balsam fir seedlings in three different stand vegetation. We compared 12 treatments and followed 120 seedlings over three growth seasons. Results: We found similar survival in soils from aspen- and spruce-dominated stands, and a greater biomass on organic layers. In addition to this, a greater mycorrhization rate was found in aspen soils but improved germination in spruce soils. The presence of Ericaceae in spruce soils was associated with lower mycorrhization but did not affect other traits. Sterilization and therefore microorganisms affected mainly the number of ectomycorrhizae and the investment in root biomass. Finally, mycorrhization and biomass were correlated, but independent from N nutrition measured in needles. Conclusions: Our results highlighted the positive effects of organic soil layers and of mycorrhization on biomass, and showed that mycorrhization was increased under aspen as compared to other stand types. Our experiment also revealed positive effects of spruce soil on fir germination and showed that fir was able to grow and survive in all conditions. Our study suggests that fir establishment is affected by belowground multi-species interactions, and therefore highlights that biotic interactions shall be taken into account to understand and predict future tree migrations in the Boreal Forest.
-
facilitation of balsam fir by trembling aspen in the Boreal Forest do ectomycorrhizal communities matter
Frontiers in Plant Science, 2019Co-Authors: Yves Bergeron, Melissande Nagati, Melanie Roy, Annie Desrochers, Sophie Manzi, Monique GardesAbstract:Succession is generally well described above-ground in the Boreal Forest, and several studies have demonstrated the role of interspecific facilitation in tree species establishment. However, the role of mycorrhizal communities for tree establishment and interspecific facilitation, has been little explored. At the ecotone between the mixed Boreal Forest, dominated by balsam fir and hardwood species, and the Boreal Forest, dominated by black spruce, several stands of trembling aspen can be found, surrounded by black spruce Forest. Regeneration of balsam fir seems to have increased in the recent decades within the Boreal Forest, and it seems better adapted to grow in trembling aspen stands than in black spruce stands, even when located in similar abiotic conditions. As black spruce stands are also covered by ericaceous shrubs, we investigated if differences in soil fungal communities and ericaceous shrubs abundance could explain the differences observed in balsam fir growth and nutrition. We conducted a study centered on individual saplings to link growth and foliar nutrient concentrations to local vegetation cover, mycorrhization rate, and mycorrhizal communities associated with balsam fir roots. We found that foliar nutrient concentrations and ramification indices (colonization by mycorrhiza per length of root) were greater in trembling aspen stands and were positively correlated to apical and lateral growth of balsam fir saplings. In black spruce stands, the presence of ericaceous shrubs near balsam fir saplings affected ectomycorrhizal communities associated with tree roots which in turn negatively correlated with N foliar concentrations. Our results reveal that fungal communities observed under aspen are drivers of balsam fir early growth and nutrition in Boreal Forest stands and may facilitate ecotone migration in a context of climate change.
-
Forest management is driving the eastern north american Boreal Forest outside its natural range of variability
Frontiers in Ecology and the Environment, 2009Co-Authors: Dominic Cyr, Sylvie Gauthier, Yves Bergeron, Christopher CarcailletAbstract:Fire is fundamental to the natural dynamics of the North American Boreal Forest. It is therefore often suggested that the impacts of anthropogenic disturbances (eg logging) on a managed landscape are attenuated if the patterns and processes created by these events resemble those of natural disturbances (eg fire). To provide Forest management guidelines, we investigate the long-term variability in the mean fire interval (MFI) of a Boreal landscape in eastern North America, as reconstructed from lacustrine (lake-associated) sedimentary charcoal. We translate the natural variability in MFI into a range of landscape age structures, using a simple modeling approach. Although using the array of possible Forest age structures provides managers with some flexibility, an assessment of the current state of the landscape suggests that logging has already caused a shift in the age-class distribution toward a stronger representation of young stands with a concurrent decrease in old-growth stands. Logging is indeed quickly forcing the studied landscape outside of its long-term natural range of variability, implying that substantial changes in management practices are required, if we collectively decide to maintain these fundamental attributes of the Boreal Forest.
-
gap dynamics and replacement patterns in gaps of the northeastern Boreal Forest of quebec
Canadian Journal of Forest Research, 2004Co-Authors: Anh Thu Pham, Louis De Grandpre, Sylvie Gauthier, Yves BergeronAbstract:The northeastern Boreal Forest of Quebec is characterized by a humid climate. Consequently, fires are less frequent and small-scale disturbances play an important role in Forest dynamics. Natural m...
-
structure composition and diversity of old growth black spruce Boreal Forest of the clay belt region in quebec and ontario
Environmental Reviews, 2003Co-Authors: Karen A Harper, Sylvie Gauthier, Pierre Drapeau, Catherine Boudreault, Louis Degrandpre, Yves BergeronAbstract:Old-growth black spruce (Picea mariana) Boreal Forest in the Clay Belt region of Ontario and Quebec is an open Forest with a low canopy, quite different from what many consider to be "old growth". ...
Charles J. Krebs - One of the best experts on this subject based on the ideXlab platform.
-
Climate change increases predation risk for a keystone species of the Boreal Forest
Nature Climate Change, 2020Co-Authors: Michael J. L. Peers, Thomas S Jung, Rudy Boonstra, Yasmine N. Majchrzak, Allyson K. Menzies, Emily K. Studd, Guillaume Bastille-rousseau, Murray Humphries, Alice J. Kenney, Charles J. KrebsAbstract:Canada lynx ( Lynx canadensis ) and snowshoe hares ( Lepus americanus ) form a keystone predator–prey cycle that has large impacts on the North American Boreal Forest vertebrate community. Snowshoe hares and lynx are both well-suited for snowy winters, but climate change-associated shifts in snow conditions could lower hare survival and alter cyclic dynamics. Using detailed monitoring of snowshoe hare cause-specific mortality, behaviour and prevailing weather, we demonstrate that hare mortality risk is strongly influenced by variation in snow conditions. Although predation risk from lynx was largely unaffected by snow conditions, coyote ( Canis latrans ) predation increased in shallow snow. Maximum snow depth in our study area has decreased 33% over the last two decades and predictions based on prolonged shallow snow indicate that future hare survival could resemble that seen during population declines. Our results indicate that climate change could disrupt cyclic dynamics in the Boreal Forest. Monitoring of snowshoe hare ( Lepus americanus ) cause-specific mortality and behaviour reveals increased risk of predation from coyote ( Canis latrans ) in shallow snow. This could disrupt the keystone Canada lynx ( Lynx canadensis )–hare predator–prey cycle in North American Boreal Forests.
-
impact of climate change on the small mammal community of the yukon Boreal Forest
Integrative Zoology, 2019Co-Authors: Charles J. Krebs, Rudy Boonstra, Alice J. Kenney, Scott B Gilbert, Stan BoutinAbstract:Long-term monitoring is critical to determine the stability and sustainability of wildlife populations, and if change has occurred, why. We have followed population density changes in the small mammal community in the Boreal Forest of the southern Yukon for 46 years with density estimates by live trapping on 3-5 unmanipulated grids in spring and autumn. This community consists of 10 species and was responsible for 9% of the energy flow in the herbivore component of this ecosystem from 1986 to 1996, but this increased to 38% from 2003 to 2014. Small mammals, although small in size, are large in the transfer of energy from plants to predators and decomposers. Four species form the bulk of the biomass. There was a shift in the dominant species from the 1970s to the 2000s, with Myodes rutilus increasing in relative abundance by 22% and Peromyscus maniculatus decreasing by 22%. From 2007 to 2018, Myodes comprised 63% of the catch, Peromyscus 20%, and Microtus species 17%. Possible causes of these changes involve climate change, which is increasing primary production in this Boreal Forest, and an associated increase in the abundance of 3 rodent predators, marten (Martes americana), ermine (Mustela ermine) and coyotes (Canis latrans). Following and understanding these and potential future changes will require long-term monitoring studies on a large scale to measure metapopulation dynamics. The small mammal community in northern Canada is being affected by climate change and cannot remain stable. Changes will be critically dependent on food-web interactions that are species-specific.
-
can camera trapping provide accurate estimates of small mammal myodes rutilus and peromyscus maniculatus density in the Boreal Forest
Journal of Mammalogy, 2016Co-Authors: Petra Villette, Thomas S Jung, Charles J. Krebs, Rudy BoonstraAbstract:Estimating population densities of small mammals (< 100g) has typically been carried out by intensive livetrapping, but this technique may be stressful to animals and the effort required is considerable. Here, we used camera traps to detect small mammal presence and assessed if this provided a feasible alternative to livetrapping for density estimation. During 2010–2012, we used camera trapping in conjunction with mark–recapture livetrapping to estimate the density of northern red-backed voles ( Myodes rutilus ) and deer mice ( Peromyscus maniculatus ) in the Boreal Forest of Yukon, Canada. Densities for these 2 species ranged from 0.29 to 9.21 animals/ha and 0 to 5.90 animals/ha, respectively, over the course of this investigation. We determined if hit window—the length of time used to group consecutive videos together as single detections or “hits”—has an effect on the correlation between hit rate and population density. The relationship between hit rate and density was sensitive to hit window duration for Myodes with R 2 values ranging from 0.45 to 0.59, with a 90-min hit window generating the highest value. This relationship was not sensitive to hit window duration for Peromyscus , with R 2 values for the tested hit windows ranging from 0.81 to 0.84. Our results indicate that camera trapping may be a robust method for estimating density of small rodents in the Boreal Forest when the appropriate hit window duration is selected and that camera traps may be a useful tool for the study of small mammals in Boreal Forest habitat.
-
ecosystem dynamics of the Boreal Forest the kluane project
Ecosystem dynamics of the boreal forest: the Kluane project., 2001Co-Authors: Charles J. Krebs, Stan Boutin, Rudy BoonstraAbstract:This book describes the Kluane Boreal Forest Ecosystem Project which operated from 1986 to 1996 in the southwestern Yukon. It begins by describing the area and its physical setting, and then the background of the project and the wisdom that had accumulated to 1986, on how this system might operate. The details of the experiments set up are presented, partly to help the reader appreciate the difficulty of working at -40 degrees and partly to aid the reader should they contemplate doing similar experiements in the future. Then they examine the three trophic levels of plants, the herbivores, and the predators in detail to provide some surprises about how the individual species operate within the overall system. Finally, they synthesize their findings in a model of the Boreal Forest vertebrate community, and provide an overview of what they have discovered and what remains to be done. Over the ten years of this project a large number of students and researchers have joined together to produce a picture which makes major advances in our understanding of the Boreal Forest ecosystem.
Stan Boutin - One of the best experts on this subject based on the ideXlab platform.
-
impact of climate change on the small mammal community of the yukon Boreal Forest
Integrative Zoology, 2019Co-Authors: Charles J. Krebs, Rudy Boonstra, Alice J. Kenney, Scott B Gilbert, Stan BoutinAbstract:Long-term monitoring is critical to determine the stability and sustainability of wildlife populations, and if change has occurred, why. We have followed population density changes in the small mammal community in the Boreal Forest of the southern Yukon for 46 years with density estimates by live trapping on 3-5 unmanipulated grids in spring and autumn. This community consists of 10 species and was responsible for 9% of the energy flow in the herbivore component of this ecosystem from 1986 to 1996, but this increased to 38% from 2003 to 2014. Small mammals, although small in size, are large in the transfer of energy from plants to predators and decomposers. Four species form the bulk of the biomass. There was a shift in the dominant species from the 1970s to the 2000s, with Myodes rutilus increasing in relative abundance by 22% and Peromyscus maniculatus decreasing by 22%. From 2007 to 2018, Myodes comprised 63% of the catch, Peromyscus 20%, and Microtus species 17%. Possible causes of these changes involve climate change, which is increasing primary production in this Boreal Forest, and an associated increase in the abundance of 3 rodent predators, marten (Martes americana), ermine (Mustela ermine) and coyotes (Canis latrans). Following and understanding these and potential future changes will require long-term monitoring studies on a large scale to measure metapopulation dynamics. The small mammal community in northern Canada is being affected by climate change and cannot remain stable. Changes will be critically dependent on food-web interactions that are species-specific.
-
Impacts of chronic anthropogenic noise from energy-sector activity on abundance of songbirds in the Boreal Forest
Conservation Biology, 2008Co-Authors: Erin M. Bayne, Lucas Habib, Stan BoutinAbstract:The effects of human activities in Forests are often examined in the context of habitat conversion. Changes in habitat structure and composition are also associated with increases in the activity of people with vehicles and equipment, which results in increases in anthropogenic noise. Anthropogenic noise may reduce habitat quality for many species, particularly those that rely on acoustic signals for communication. We compared the density and occupancy rate of Forest passerines close to versus far from noise-generating compressor stations and noiseless well pads in the Boreal Forest of Alberta, Canada. Using distance-based sampling, we found that areas near noiseless energy facilities had a total passerine density 1.5 times higher than areas near noise-producing energy sites. The White-throated Sparrow (Zonotrichia albicollis), Yellow-rumped Warbler (Dendroica coronata), and Red-eyed Vireo (Vireo olivaceus) were less dense in noisy areas. We used repeat sampling to estimate occupancy rate for 23 additional species. Seven had lower conditional or unconditional occupancy rates near noise-generating facilities. One-third of the species examined showed patterns that supported the hypothesis that abundance is influenced by anthropogenic noise. An additional 4 species responded negatively to edge effects. To mitigate existing noise impacts on birds would require approximately $175 million. The merits of such an effort relative to other reclamation actions are discussed. Nevertheless, given the $100 billion energy-sector investment planned for the Boreal Forest in the next 10 years, including noise suppression technology at the outset of construction, makes noise mitigation a cost-effective best-management practice that might help conserve high-quality habitat for Boreal birds.
-
ecosystem dynamics of the Boreal Forest the kluane project
Ecosystem dynamics of the boreal forest: the Kluane project., 2001Co-Authors: Charles J. Krebs, Stan Boutin, Rudy BoonstraAbstract:This book describes the Kluane Boreal Forest Ecosystem Project which operated from 1986 to 1996 in the southwestern Yukon. It begins by describing the area and its physical setting, and then the background of the project and the wisdom that had accumulated to 1986, on how this system might operate. The details of the experiments set up are presented, partly to help the reader appreciate the difficulty of working at -40 degrees and partly to aid the reader should they contemplate doing similar experiements in the future. Then they examine the three trophic levels of plants, the herbivores, and the predators in detail to provide some surprises about how the individual species operate within the overall system. Finally, they synthesize their findings in a model of the Boreal Forest vertebrate community, and provide an overview of what they have discovered and what remains to be done. Over the ten years of this project a large number of students and researchers have joined together to produce a picture which makes major advances in our understanding of the Boreal Forest ecosystem.
Rudy Boonstra - One of the best experts on this subject based on the ideXlab platform.
-
Climate change increases predation risk for a keystone species of the Boreal Forest
Nature Climate Change, 2020Co-Authors: Michael J. L. Peers, Thomas S Jung, Rudy Boonstra, Yasmine N. Majchrzak, Allyson K. Menzies, Emily K. Studd, Guillaume Bastille-rousseau, Murray Humphries, Alice J. Kenney, Charles J. KrebsAbstract:Canada lynx ( Lynx canadensis ) and snowshoe hares ( Lepus americanus ) form a keystone predator–prey cycle that has large impacts on the North American Boreal Forest vertebrate community. Snowshoe hares and lynx are both well-suited for snowy winters, but climate change-associated shifts in snow conditions could lower hare survival and alter cyclic dynamics. Using detailed monitoring of snowshoe hare cause-specific mortality, behaviour and prevailing weather, we demonstrate that hare mortality risk is strongly influenced by variation in snow conditions. Although predation risk from lynx was largely unaffected by snow conditions, coyote ( Canis latrans ) predation increased in shallow snow. Maximum snow depth in our study area has decreased 33% over the last two decades and predictions based on prolonged shallow snow indicate that future hare survival could resemble that seen during population declines. Our results indicate that climate change could disrupt cyclic dynamics in the Boreal Forest. Monitoring of snowshoe hare ( Lepus americanus ) cause-specific mortality and behaviour reveals increased risk of predation from coyote ( Canis latrans ) in shallow snow. This could disrupt the keystone Canada lynx ( Lynx canadensis )–hare predator–prey cycle in North American Boreal Forests.
-
impact of climate change on the small mammal community of the yukon Boreal Forest
Integrative Zoology, 2019Co-Authors: Charles J. Krebs, Rudy Boonstra, Alice J. Kenney, Scott B Gilbert, Stan BoutinAbstract:Long-term monitoring is critical to determine the stability and sustainability of wildlife populations, and if change has occurred, why. We have followed population density changes in the small mammal community in the Boreal Forest of the southern Yukon for 46 years with density estimates by live trapping on 3-5 unmanipulated grids in spring and autumn. This community consists of 10 species and was responsible for 9% of the energy flow in the herbivore component of this ecosystem from 1986 to 1996, but this increased to 38% from 2003 to 2014. Small mammals, although small in size, are large in the transfer of energy from plants to predators and decomposers. Four species form the bulk of the biomass. There was a shift in the dominant species from the 1970s to the 2000s, with Myodes rutilus increasing in relative abundance by 22% and Peromyscus maniculatus decreasing by 22%. From 2007 to 2018, Myodes comprised 63% of the catch, Peromyscus 20%, and Microtus species 17%. Possible causes of these changes involve climate change, which is increasing primary production in this Boreal Forest, and an associated increase in the abundance of 3 rodent predators, marten (Martes americana), ermine (Mustela ermine) and coyotes (Canis latrans). Following and understanding these and potential future changes will require long-term monitoring studies on a large scale to measure metapopulation dynamics. The small mammal community in northern Canada is being affected by climate change and cannot remain stable. Changes will be critically dependent on food-web interactions that are species-specific.
-
can camera trapping provide accurate estimates of small mammal myodes rutilus and peromyscus maniculatus density in the Boreal Forest
Journal of Mammalogy, 2016Co-Authors: Petra Villette, Thomas S Jung, Charles J. Krebs, Rudy BoonstraAbstract:Estimating population densities of small mammals (< 100g) has typically been carried out by intensive livetrapping, but this technique may be stressful to animals and the effort required is considerable. Here, we used camera traps to detect small mammal presence and assessed if this provided a feasible alternative to livetrapping for density estimation. During 2010–2012, we used camera trapping in conjunction with mark–recapture livetrapping to estimate the density of northern red-backed voles ( Myodes rutilus ) and deer mice ( Peromyscus maniculatus ) in the Boreal Forest of Yukon, Canada. Densities for these 2 species ranged from 0.29 to 9.21 animals/ha and 0 to 5.90 animals/ha, respectively, over the course of this investigation. We determined if hit window—the length of time used to group consecutive videos together as single detections or “hits”—has an effect on the correlation between hit rate and population density. The relationship between hit rate and density was sensitive to hit window duration for Myodes with R 2 values ranging from 0.45 to 0.59, with a 90-min hit window generating the highest value. This relationship was not sensitive to hit window duration for Peromyscus , with R 2 values for the tested hit windows ranging from 0.81 to 0.84. Our results indicate that camera trapping may be a robust method for estimating density of small rodents in the Boreal Forest when the appropriate hit window duration is selected and that camera traps may be a useful tool for the study of small mammals in Boreal Forest habitat.
-
ecosystem dynamics of the Boreal Forest the kluane project
Ecosystem dynamics of the boreal forest: the Kluane project., 2001Co-Authors: Charles J. Krebs, Stan Boutin, Rudy BoonstraAbstract:This book describes the Kluane Boreal Forest Ecosystem Project which operated from 1986 to 1996 in the southwestern Yukon. It begins by describing the area and its physical setting, and then the background of the project and the wisdom that had accumulated to 1986, on how this system might operate. The details of the experiments set up are presented, partly to help the reader appreciate the difficulty of working at -40 degrees and partly to aid the reader should they contemplate doing similar experiements in the future. Then they examine the three trophic levels of plants, the herbivores, and the predators in detail to provide some surprises about how the individual species operate within the overall system. Finally, they synthesize their findings in a model of the Boreal Forest vertebrate community, and provide an overview of what they have discovered and what remains to be done. Over the ten years of this project a large number of students and researchers have joined together to produce a picture which makes major advances in our understanding of the Boreal Forest ecosystem.
Melissande Nagati - One of the best experts on this subject based on the ideXlab platform.
-
importance of soil stand and mycorrhizal fungi in abies balsamea establishment in the Boreal Forest
Forests, 2020Co-Authors: Melissande Nagati, Yves Bergeron, Melanie Roy, Annie Desrochers, Monique GardesAbstract:Research highlights: To understand differences in the establishment of balsam fir regeneration observed in the Boreal Forest, we examined how soil layer and microorganisms explained differences in growth and mycorrhization in three different stand types. Our experiment revealed positive and negative effects on growth of seedlings, and highlights the importance of biotic interactions in balsam fir establishment. Background and Objectives: In a context of climate change, understanding tree migration can be examined through changes in tree regeneration. At the ecotone between mixed and conifer Boreal Forest, regeneration of balsam fir northward is of particular interest because it thrives better under aspen-dominated stands as compared to adjacent spruce-dominated stands. As the understorey differs between these stands, with more Ericaceae under spruce and different ectomycorrhizal fungal communities in organic and mineral horizons, we hypothesized that biotic factors could explain differences in balsam fir establishment. Materials and Methods: Using a growth chamber experiment, we tested if differences in soil layers and modification of soil fungal communities would affect germination, mycorrhization, and growth of balsam fir seedlings in three different stand vegetation. We compared 12 treatments and followed 120 seedlings over three growth seasons. Results: We found similar survival in soils from aspen- and spruce-dominated stands, and a greater biomass on organic layers. In addition to this, a greater mycorrhization rate was found in aspen soils but improved germination in spruce soils. The presence of Ericaceae in spruce soils was associated with lower mycorrhization but did not affect other traits. Sterilization and therefore microorganisms affected mainly the number of ectomycorrhizae and the investment in root biomass. Finally, mycorrhization and biomass were correlated, but independent from N nutrition measured in needles. Conclusions: Our results highlighted the positive effects of organic soil layers and of mycorrhization on biomass, and showed that mycorrhization was increased under aspen as compared to other stand types. Our experiment also revealed positive effects of spruce soil on fir germination and showed that fir was able to grow and survive in all conditions. Our study suggests that fir establishment is affected by belowground multi-species interactions, and therefore highlights that biotic interactions shall be taken into account to understand and predict future tree migrations in the Boreal Forest.
-
facilitation of balsam fir by trembling aspen in the Boreal Forest do ectomycorrhizal communities matter
Frontiers in Plant Science, 2019Co-Authors: Yves Bergeron, Melissande Nagati, Melanie Roy, Annie Desrochers, Sophie Manzi, Monique GardesAbstract:Succession is generally well described above-ground in the Boreal Forest, and several studies have demonstrated the role of interspecific facilitation in tree species establishment. However, the role of mycorrhizal communities for tree establishment and interspecific facilitation, has been little explored. At the ecotone between the mixed Boreal Forest, dominated by balsam fir and hardwood species, and the Boreal Forest, dominated by black spruce, several stands of trembling aspen can be found, surrounded by black spruce Forest. Regeneration of balsam fir seems to have increased in the recent decades within the Boreal Forest, and it seems better adapted to grow in trembling aspen stands than in black spruce stands, even when located in similar abiotic conditions. As black spruce stands are also covered by ericaceous shrubs, we investigated if differences in soil fungal communities and ericaceous shrubs abundance could explain the differences observed in balsam fir growth and nutrition. We conducted a study centered on individual saplings to link growth and foliar nutrient concentrations to local vegetation cover, mycorrhization rate, and mycorrhizal communities associated with balsam fir roots. We found that foliar nutrient concentrations and ramification indices (colonization by mycorrhiza per length of root) were greater in trembling aspen stands and were positively correlated to apical and lateral growth of balsam fir saplings. In black spruce stands, the presence of ericaceous shrubs near balsam fir saplings affected ectomycorrhizal communities associated with tree roots which in turn negatively correlated with N foliar concentrations. Our results reveal that fungal communities observed under aspen are drivers of balsam fir early growth and nutrition in Boreal Forest stands and may facilitate ecotone migration in a context of climate change.