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Abstract: Aim: To determine the relationships between the functional trait composition of forest communities and environmental gradients across scales and biomes and the role of species relative abundances in these relationships. Location: Global. Time period: Recent. Major taxa studied: Trees. Methods: We integrated species abundance records from worldwide forest inventories and associated functional traits (wood density, specific leaf area and seed mass) to obtain a data set of 99,953 to 149,285 plots (depending on the trait) spanning all forested continents. We computed community‐weighted and unweighted means of trait values for each plot and related them to three broad environmental gradients and their interactions (energy availability, precipitation and soil properties) at two scales (global and biomes). Results: Our models explained up to 60% of the variance in trait distribution. At global scale, the energy gradient had the strongest influence on traits. However, within‐biome models revealed different relationships among biomes. Notably, the functional composition of tropical forests was more influenced by precipitation and soil properties than energy availability, whereas temperate forests showed the opposite pattern. Depending on the trait studied, response to gradients was more variable and proportionally weaker in boreal forests. Community unweighted means were better predicted than weighted means for almost all models. Main conclusions: Worldwide, trees require a large amount of energy (following latitude) to produce dense wood and seeds, while leaves with large surface to weight ratios are concentrated in temperate forests. However, patterns of functional composition within‐biome differ from global patterns due to biome specificities such as the presence of conifers or unique combinations of climatic and soil properties. We recommend assessing the sensitivity of tree functional traits to environmental changes in their geographic context. Furthermore, at a given site, the distribution of tree functional traits appears to be driven more by species presence than species abundance.

Fire reconstruction and forest inventory maps provided an opportunity to study changes in stand-level characteristics following fire using a data set comprised of all forest stands of fire origin in an area of over 10Â 000 km2. We assigned the date of the most recent fire occurrence to over 31Â 000 forest stands in an ecoforestry database. We categorized stands on different substrates into age classes to investigate differences in canopy composition, cover and height, and incidence of secondary disturbance. Stands with over 75% Picea mariana (Mill.) BSP dominated all age classes on organic sites. On other substrates, there was a change in canopy composition from deciduous stands and stands dominated by Pinus banksiana Lamb. to Picea mariana stands after about 100 yr. This transition was later for xeric sites. After a peak in canopy cover and height at about 100 yr, there was a decrease in the area occupied by stands with dense, tall canopies. Structural development was slower on less productive sites. There was little incidence of spruce budworm outbreaks. Partial disturbance by windthrow coincided with canopy break-up at 100 yr, but appeared to have little effect on overall canopy structure in later stages. Structural diversity was independent of compositional diversity; on organic sites, stands with similar composition had different canopy structure. Diversity of stands with different composition and structure was greatest in the first 150 yr following fire. Maintaining stands in different stages of structural development on the landscape would serve to maintain regional biodiversity.

Introduction: In eastern Canada, the boreal forest is associated with an important latitudinal shift in forest composition and structure, which occurs in the transition between the mixed southern boreal forest and the coniferous northern boreal forest. Along this transition, upland mixedwood stands with large deciduous trees (important for cavity-dependent vertebrate species) are gradually replaced by forests with smaller conifer trees, primarily black spruce (Picea mariana). Concomitantly, the availability of lowland forests flooded by the American beaver (Castor canadensis), which can provide adequate conditions for tree-cavity users, is also decreasing. Methods: We hypothesized that this latitudinal gradient would bring important changes in the functional diversity and network structure of vertebrate cavity- using communities. Along this latitudinal gradient we used a nest web approach to analyze the structure and robustness of networks of cavity users in upland forests and in lowland forests flooded by beavers. Results: Despite their low availability in the northern forest region, we found that mixedwood stands persisted throughout the boreal forest in being the main drivers of nest webs network structure of upland forests whereas old black spruce stands contribution was low. In lowland forests, beaver ponds harbored nest webs with a rich and complex structure in both forest regions. Species removal simulations revealed that across our latitudinal gradient upland and lowland forest nest webs responded differently. In upland forests, the removal of trembling aspen and the Pileated Woodpecker (Dryocopus pileatus) caused the highest proportions of secondary extinctions, showing low robustness of nest webs given that these two species were highly connected to the other species. Contrastingly, nest webs in beaver ponds were more robust mainly because excavator species used a higher diversity of tree species despite the removal of the Northern Flicker (Colaptes auratus) which induced numerous secondary extinctions. The Pileated Woodpecker remained the pivotal species across the two forest regions in upland forests whereas the Northern Flicker became the main large cavity provider in beaver ponds across the latitudinal gradient. Discussion: We discuss how mixedwood forests and beaver ponds, which are key habitat types for the cavity-using vertebrate community across our latitudinal gradient, should be maintained and protected in landscapes under industrial timber harvesting. [ABSTRACT FROM AUTHOR]

The Canadian boreal forest biome has been subjected to a long history of management for wood production. Here, we examined the cumulative impacts of logging on older forests in terms of area, distribution and patch configuration in the managed forest zones of the Eastern Canadian provinces of Ontario and Quebec. We also examined the consequences of these cumulative impacts on a once widely distributed and now threatened species, the woodland caribou (Rangifer tarandus caribou). The cumulative area of recently logged forest (since ~1976) was 14,024,619 ha, with 8,210,617 ha in Quebec and 5,814,002 ha in Ontario. The total area of older forests was 21,249,341 ha, with 11,840,474 ha in Quebec and 9,408,867 ha in Ontario. Patch statistics revealed that there were 1,085,822 older forests with core patches < 0.25 ha and an additional 603,052 < 1.0 ha. There were 52 > 10,00–50,000 ha and 8 < 50,000 ha. Older forest patches (critical caribou habitat) in the 21 local population ranges totalled 6,103,534 ha, distributed among ~387,102 patches with 362,933 < 10 ha and 14 > 50,000 ha. The median percentage of local population ranges that was disturbed was 53.5%, with Charlevoix having the maximum (90.3%) and Basse Côte-Nord the least (34.9%). Woodland caribou local population ranges with disturbed suitable habitats >35% are considered unable to support self-sustaining populations. We found that for the 21 caribou local population ranges examined, 3 were at very high risk (>75% area disturbed), 16 at high risk (>45 ≤ 75% area disturbed), and 2 at low risk (≤35% area disturbed). Major changes are needed in boreal forest management in Ontario and Quebec for it to be ecologically sustainable, including a greater emphasis on protection and restoration for older forests, and to lower the risks for caribou populations. [ABSTRACT FROM AUTHOR]

The main environmental factors that drive lichen communities are still poorly known in northern boreal ecosystems. This study compares the effects of forest stand characteristics (height, canopy cover, and age) on fruticose epiphytic and terricolous lichen communities across a large region located at the interface between closed-crown boreal forests and northern open woodlands in the province of Quebec (Canada). The dataset consists of 875 plots spread across a 242 000 [km.sup.2] territory that ranges from the eastern to the western extremities of the province. The biomass of fruticose epiphytic lichens (Alectoria, Bryoria, Evernia, and Usnea) was evaluated at the branch, tree, and plot levels, and terricolous lichen cover (Cladonia spp.) was evaluated at the plot level. The results indicate that epiphytic and terricolous lichens respond significantly but differently to variations in forest characteristics. At the plot level, epiphytic lichen biomass was highest in the oldest stands (>100 years) and lowest in stand with low canopy cover (40%) or stands of intermediate age (60 to 100 years old). Species composition of epiphytic communities was also examined, and some species or genera exhibit a strong association with older stands (Alectoria sarmentosa (Ach.) Ach., Bryoria spp.) or with specific regions along the ca. 1500 km east-west gradient (Evernia mesomorpha Nyl. in the western part, Bryoria spp. in the central part, and A sarmentosa in the eastern part). In terms of conservation, these results indicate that epiphytic lichens communities are potentially sensitive to the preferential logging of older stands. Both epiphytic and terricolous lichen communities are also potentially sensitive to expected climate change effects such as increased fire frequencies or increased forest growth. Key words: lichen, boreal forest, epiphytes, Bryoria, Cladonia. Les principaux facteurs qui determinent la composition des communautes de lichens sont encore mal connus dans les ecosystemes boreaux nordiques. Cette etude compare les effets des caracteristiques (hauteur, couvert forestier et age) des peuplements forestiers sur les communautes de lichens epiphytes fruticuleux et terricoles a travers une vaste region situee a la limite ente les forets boreales a couvert ferme et les forets nordiques ouvertes dans la province de Quebec (Canada). Le jeu de donnees est compose de 875 placettes reparties sur un territoire de 242 000 [km.sup.2] qui s'etend entre les extremites est et ouest de la province. La biomasse des lichens epiphytes fruticuleux (Alectoria, Bryoria, Evernia et Usnea) a ete evaluee a l'echelle de la branche, de l'arbre et de la placette; le recouvrement de lichens terricoles (Cladonia spp.) a ete evalue a l'echelle de la placette. Les resultats montrent que les lichens epiphytes et terricoles reagissent de facon significative mais differente aux variations des caracteristiques de la foret. A l'echelle de la placette, la biomasse des lichens epiphytes etait la plus elevee dans les plus vieux peuplements (>100 ans), et la plus faible dans les peuplements avec un faible couvert forestier (40 %) ou dans les peuplements d'age intermediaire (60-100 ans). La composition en especes des communautes epiphytes a egalement ete etudiee et certaines especes ou genres etaient etroitement associes aux peuplements plus vieux (Alectoria sarmentosa (Ach.) Ach., Bryoria spp.), ou a des regions particulieres le long du gradient est-ouest d'environ 1500 km (Evernia mesomorpha Nyl. a l'ouest, Bryoria spp. au centre et A. sarmentosa a l'est). En termes de conservation, ces resultats indiquent que les communautes de lichens epiphytes sont potentiellement sensibles a l'exploitation preferentielle des vieux peuplements. Les communautes de lichens epiphytes et terricoles sont aussi potentiellement sensibles aux effets apprehendes des changements climatiques tels que l'augmentation de la frequence des feux ou l'augmentation de la croissance de la foret. [Traduit par la Redaction] Mots-cles: lichen, foret boreale, epiphytes, Bryoria, Cladonia., Introduction The northern boreal zone is at the transition between the closed-crown boreal forest (to the south) and the open taiga (to the north). In North America, this ecosystem is [...]

Idiopathic scoliosis (IS) is a spine deformity that affects approximately 3% of the population. The underlying causes of IS are not well understood, although there is clear evidence that there is a genetic component to the disease. Genetic mapping studies suggest high genetic heterogeneity, but no IS disease-causing gene has yet been identified. Here, genetic linkage analyses combined with exome sequencing identified a rare missense variant (p.A446T) in the centriolar protein gene POC5 that cosegregated with the disease in a large family with multiple members affected with IS. Subsequently, the p.A446T variant was found in an additional set of families with IS and in an additional 3 cases of IS. Moreover, POC5 variant p.A455P was present and linked to IS in one family and another rare POC5 variant (p.A429V) was identified in an additional 5 cases of IS. In a zebrafish model, expression of any of the 3 human IS-associated POC5 variant mRNAs resulted in spine deformity, without affecting other skeletal structures. Together, these findings indicate that mutations in the POC5 gene contribute to the occurrence of IS., Introduction Idiopathic scoliosis (IS) is a 3D spinal deformity characterized by lateral curvature of the spine of 10° or more, as measured by Cobb's method, and rotation of the vertebral [...]