mardi 10 février 2026

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-LapointeFrontiers 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).

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.

lundi 9 février 2026

dimanche 4 janvier 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.

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.