Interplay of biotic and abiotic factors shapes tree seedling growth and root-associated microbial communities

Interplay of biotic and abiotic factors shapes tree seedling growth and root-associated microbial communities

Joey Chamard, Maria Faticov, F. Guillaume Blanchet, Pierre-Luc Chagnon & Isabelle Laforest-Lapointe - Nature: Communications Biology volume 7, Article number: 360 -  22 March 2024

... we use root microscopy, coupled with amplicon sequencing, to study bacterial, fungal, and mycorrhizal root-associated microbial communities from sugar maple seedlings distributed across two temperate-to-boreal elevational gradients in southern Québec, Canada. Our findings demonstrate that soil pH, soil Ca, and distance to sugar maple trees are key drivers of root-associated microbial communities, overshadowing the influence of elevation. Interestingly, changes in root fungal community composition mediate an indirect effect of soil pH on seedling growth, a pattern consistent at both sites. Overall, our findings highlight a complex role of biotic and abiotic factors in shaping tree-microbe interactions, which are in turn correlated with seedling growth. These findings have important ramifications for tree range expansion in response to shifting climatic niches.

Les alliés invisibles des érablières

Joey Chamard - Le Climatoscope - 25 octobre 2021

... les changements climatiques constituent un des principaux phénomènes pouvant menacer la productivité de nos érablières. Ces changements impliquent notamment une augmentation de la température moyenne annuelle ainsi qu’une intensification des phénomènes climatiques extrêmes, qui se traduisent par une plus grande fréquence de sécheresses et d’inondations. Les érables à sucre sont des organidsmes particulièrement vulnérables à ces changements climatiques puisqu’ils ont une longue espérance de vie, atteignent tardivement leur maturité sexuelle et migrent lentement ... La perspective de cette migration entraîne une nouvelle question fondamentale : les sols en régions boréales et leurs communautés microbiennes permettront-ils à l’érable à sucre de s’y établir et compétitionner avec d’autres essences forestières?  Cet article constitue une présentation sommaire de l’importance des interactions plantes-microorganismes dans un contexte de changements climatiques. Il traite plus particulièrement de la situation de l’érable à sucre au Québec, de l’écologie de ses symbiotes fongiques ainsi que des perspectives innovantes que représentent les communautés synthétiques.

Lien: pdf 

Variation in the leaf and root microbiome of sugar maple (Acer saccharum) at an elevational range limit

Variation in the leaf and root microbiome of sugar maple (Acer saccharum) at an elevational range limit

Jessica Wallace​, Isabelle Laforest-Lapointe​, Steven W. Kembel -  PeerJ - August 14, 2018

In this study, we quantified the microbial communities of the leaves and roots of seedlings of the deciduous tree species sugar maple (Acer saccharum Marshall) within its natural range and at the species’ elevational range limit at Mont-Mégantic, Quebec ... The bacterial and fungal communities of A. saccharum seedlings differ across elevational range limits for all four plant compartments. Distinct microbial communities colonize each compartment, although the microbial communities inside a plant’s structure (endophytes) were found to be a subset of the communities found outside the plant’s structure (epiphytes) ... These findings provide a greater understanding of the ecological processes driving the structure and diversity of plant-associated microbial communities within and at the edge of a plant species range, and suggest the potential for biotic interactions between plants and their associated microbiota to influence the dynamics of plant range edge boundaries and responses to global change.

Vermont launches new weather network to improve flood prediction

Vermont launches new weather network to improve flood prediction

Beth McDermott - Burlington Free Press - May 13, 2026

The University of Vermont has opened the first station in the Vermont Mesonet, a planned statewide system of automated weather stations that will provide local data for flood preparedness, farm planning and research, according to a community announcement ... While other automated weather stations exist in Vermont for aviation and fire safety, the Vermont Mesonet is expected to be the first system focused on observing localized, rapidly changing weather events such as thunderstorms and flooding.

New Advanced Weather Station Will Be Part of Vermont’s ‘Mesonet’

Sasha Goldstein - May 6, 2026

The 30-foot-high tower in Lyndonville is one of 21 planned for Vermont. It can measure meteorological conditions and help Vermonters prepare for dangerous weather.

Experts hope statewide network will help keep Vermonters informed during extreme weather

Abagael Giles - Vermont Public - May 5, 2026

UVM unveiled the first station in the Vermont Mesonet network Tuesday at the Caledonia County Fairgrounds in Lyndonville. At 30 feet tall, the new tower is outfitted with sensors to detect wind speed and direction, multiple thermometers, a snow depth sensor and a rain gauge, among other instruments. Together, they’ll take measurements every five minutes of things like wind speed, soil saturation and relative humidity.

UVM begins development of a statewide weather monitoring network

Vermont Business Magazine - 05/07/2026

Archive

Festi’Bois 2026

The Great Tick Illusion — Rethinking Where They Come From

The Great Tick Illusion — Rethinking Where They Come From 

Adam Harrington - Learn your Land - 27 April 2026

For a long time, we’ve been told that ticks are simply moving north as the climate changes. But interestingly, a recent preprint study challenges this assumption. It turns out that the history of the tick on our landscape is far more complex and ancient than we realized.

Le héron, le vison et le grand brochet

Why Eastern Forests Don’t Grow 300-Foot Trees

Why Eastern Forests Don’t Grow 300-Foot Trees

Adam Harrington - Learn your Land - March 25, 2026

It’s a question that leads to an interesting realization: Forests in eastern North America are known for their exceptional biodiversity, but none of the trees that grow in these forests attain the heights that the tallest trees out west reach. Why is this the case? Is it a lack of rain? Is it the soil? Or are there other factors involved?

Beavers are turning rivers into powerful carbon sinks

Beavers can convert stream corridors to persistent carbon sinks
Lukas Hallberg et al - 18 March 2026 - Nature
Recent reintroductions of the Eurasian beaver (Castor fiber) across Europe represents an ecological shift with potential implications for carbon cycling in stream corridors. We present a comprehensive carbon budget of a beaver-influenced stream corridor ... Annually, the beaver wetland was a net carbon sink (98.3 ± 34.4 t yr-1), driven by subsurface removal of dissolved inorganic carbon.
Beavers can turn streams into carbon stores – we measured how much
Jonathan Larsen, Annegret Larsen, Lukas Hallberg - The Conversation - March 18, 2026
Across Europe, beaver numbers are increasing after a long period of decline. As these aquatic mammals recolonise rivers, they are gradually rebuilding wetlands that once existed across many river valleys ... Over just 13 years, the wetland we studied in northern Switzerland locked away more than 1,100 tonnes of carbon. That’s comparable to two Olympic swimming pools filled with charcoal ... When a dam slows the water, sediments begin to settle. These sediments carry organic material such as leaves, soil and plant fragments that contain carbon. Instead of washing away downstream, the material becomes buried in wetland soils.

Beavers might be one of nature’s most unexpected allies in locking away carbon and fighting climate change.
Science Daily - March 22, 2026
Over just 13 years, a beaver-engineered wetland in Switzerland stored over a thousand tonnes of carbon—up to ten times more than similar areas without beavers.
Groundbreaking study finds a natural way to fight climate change
Doyle Rice - USA Today - March 22, 2026
The new research, published on March 18 in the journal Communications Earth & Environment, has, for the first time, calculated the carbon dioxide emitted and sequestered due to engineering work by beavers in suitable wetland areas.

The temperate forest phyllosphere and rhizosphere microbiome: a case study of sugar maple

The temperate forest phyllosphere and rhizosphere microbiome: a case study of sugar maple

Enea M, Beauregard J, De Bellis T, Faticov M and Isabelle Laforest-Lapointe - Frontiers in Microbiology  - 14 January 2025 

To prevent sugar maple from declining in the face of global change, it will be crucial to gain a better understanding (1) of its capacity to shift north in pace with climatic changes and (2) of the contributions of surrounding microbial communities in this process. ... sugar maple assembles diverse and species-specific root and leaf microbiomes, with potential impacts on tree growth, immunity, and survival. First, the origin of the soil on which sugar maple grows appears to play a key role. Despite improved regeneration under colder temperatures, which corresponds to current northern range limit climatic conditions, sugar maple survival and biomass after transplants are up to 50% higher on soil from the center of its range. This suggests that this tree species is highly dependent on root biotic interactions (e.g., in the rhizosphere with arbuscular mycorrhizae) for successful establishment in a newly available niche or in adaptation to climate change, irrespective of the physico-chemical properties of the soil. Second, sugar maple leaves have also been the focus of several studies on tree-microbe interactions in the phyllosphere, demonstrating that the local abiotic environment of trees drives leaf microbial colonization (Laforest-Lapointe et al., 2016a; Wallace et al., 2018).

Regional variation drives differences in microbial communities associated with sugar maple across a latitudinal range

Tonia De Bellis, Isabelle Laforest-Lapointe, Kevin A. Solarik, Dominique Gravel, Steven W. Kembel - Ecology - 12 April 2022

We collected sugar maple seeds from across the species current range, then planted them in temperate and mixedwood/transitional forests (current range) and in the boreal region (beyond range but predicted future range in response to climate change). ... Variation among sites and regions were the main drivers of the differences in host microbial communities, whereas seed provenance did not play a large role ....  Along the latitudinal gradient, we (1) observed reductions in mycorrhizal diversity that can negatively impact maple establishment; (2) and revealed reductions in fungal leaf pathogens that can have opposite effects. Our results highlight the need for an integrated approach including the examination of various microbial taxa on different plant compartments to improve our understanding of plant range shifts and plant–microbe interactions.

Extreme Cold has an Impact on Trees and Invasive Insects

Extreme Cold has an Impact on Trees and Invasive Insects
NorthMetroTV - February 2026

Densité et succès reproducteur de la grive des bois (Hylocichla mustelina) dans les parcs nationaux d’Oka et du Mont-Saint-Bruno

Densité et succès reproducteur de la grive des bois (Hylocichla mustelina) dans les parcs nationaux d’Oka et du Mont-Saint-Bruno

Marc-André Villard, Thierry Grandmont, Mathieu Lemay and René Charest - Le Naturaliste canadien - Volume 148, Number 1, Spring 2024

La grive des bois (Hylocichla mustelina) a été désignée espèce menacée au Canada en 2012. De 1970 à 2021, ses effectifs auraient chuté de 75 % au Canada et de 84 % au Québec. La présente étude visait à déterminer le statut de l’espèce dans 2 parcs nationaux de la région de Montréal. En 2021 et en 2022, 88 nids ont été trouvés dans le parc national d’Oka, contre 10 au parc national du Mont-Saint-Bruno (2022). La densité de nids était nettement inférieure à Mont-Saint-Bruno (0,03/ha versus 0,10/ha), possiblement en raison du surbroutement de la végétation par le cerf de Virginie (Odocoileus virginianus). Les taux de survie des nids variaient d’un parc à l’autre et d’une année à l’autre (Oka : 68,2 % en 2021 et 27,6 % en 2022 ; Mont-Saint-Bruno : 68,9 %). La cause principale d’échec des nids était la prédation. Le taux de parasitisme par le vacher à tête brune (Molothrus ater) était plus élevé à Mont-Saint-Bruno (25 % versus 1,9 %). À Oka, la prédation des nids était plus forte chaque année le long du sentier le plus fréquenté, ce qui suggère un effet négatif du taux de passage des visiteurs sur le succès des nids.

The Wood Thrush (Hylocichla mustelina) was listed as Threatened in Canada in

2012. Between 1970 and 2021, its numbers are estimated to have declined by

75% nationally, and by 84% in the province of Québec. The aim of the present

study was to document the status of this species in two national parks in the

Montréal region. Eighty-eight nests were found in Oka National Park (parc

national d’Oka, 2021 and 2022 combined), and 10 in Mont-Saint-Bruno National

Park (parc national du Mont-Saint-Bruno, 2022). Nest density was substantially

lower at the Mont-Saint-Bruno site (0.03/ha versus 0.10/ha), possibly due to

overbrowsing by white-tailed deer (Odocoileus virginianus). Nest survival rate

varied as a function of location and year: Oka: 68.2% in 2021 and 27.6% in

2022; Mont-Saint-Bruno: 68.9%. The main cause of nest failure was predation.

The rate of brood parasitism by brown-headed cowbird (Molothrus ater) was

higher at Mont-Saint-Bruno (25% versus 1.9%). In Oka, nest predation was

higher along the most heavily used trail in both study years, suggesting a

negative impact of trail use by visitors on nest success.

Losing the edge: How wood thrush population trends differ in different parts of their range

Losing the edge: How wood thrush population trends differ in different parts of their range

Dr. Rémi Torrenta - Birds Canada/Oiseaux Canada - 18 August 2022

Focusing mostly on breeding populations in Ontario and Québec, we found important differences between populations of the St. Lawrence Lowlands, located at the inner core of the species’ Canadian breeding range, and populations of the Canadian Shield, located at the edge of its Canadian breeding range. The population in the core was surprisingly stable despite high rates of forest loss and fragmentation. At the edge of its range, Wood Thrush populations may be more at risk of local extinction due to a combination of factors: lower habitat quality and prey availability, but also fewer new birds moving into these areas (i.e., lower immigration) ... the first important thing to mention is that those forest fragments have a dense understory layer, which has been very favorable to the Wood Thrush, especially following regeneration after the 1998 ice storm. The other thing we found is that young birds moving into these fragments from larger forests (i.e., natal dispersal) may compensate for the low number of young produced within these fragments, thus “subsidizing” this fragile population.

Links/Liens: Research paper/Article de recherche, 

Echoes of the Forest: Tracking the Journey of the Wood Thrush

Echoes of the Forest: Tracking the Journey of the Wood Thrush: A two-year study aimed at the conservation of one of Vermont’s treasured songbirds
Pete Patrick - Audubon Vermont - September 02, 2025

During breeding season, Wood Thrush prefer mature deciduous or mixed forests with tall trees and a dense understory for foraging and nesting. Unfortunately, both of these habitats are experiencing fragmentation which leads to limited access to quality food and shelter ... Declines in Wood Thrush populations have been especially prevalent in the northeastern regions of their range, with an overall population loss of 59% since 1970. ... As such, scientists have noticed a decades-long trend of population decline. In response to this decline the U.S. Fish and Wildlife Service recruited bird banders and organizations, like Audubon Vermont, for the Wood Thrush Nanotagging Program, colloquially named WOTH Party. WOTH Party is a two-year study that tracks the movements and behavior of Wood Thrush in their breeding and wintering grounds using nanotags.