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Peatlands could become important foraging habitats, and their plant communities threatened, in areas with an overabundance of large herbivores. Peatland response to herbivore exclusion may vary widely according to abiotic [...]

Abstract: The American ginseng (Panax quinquefolius L.) has been used for a wide range of medicinal purposes for more than 300 years, and is at risk in most of its [...]

Abstract: Herbarium specimens can be used to reconstruct spatiotemporal changes in plant morphology caused by environmental pressures. The reliability of herbarium-derived data requires evaluation, because specimen collection is subject to [...]

Gray birch (Betula populifolia Marshall) is a pioneer tree species that generally colonizes both poor, dry soils and disturbed sites. Its current range appears to be expanding, and it has been observed to establish gradually and often massively in ombrotrophic peatlands. We examined data from sites within and beyond its continuous range that have been subjected to macrofossil analyses to determine whether this species was more abundant during certain periods since deglaciation. The most abundant macroremains were found in the eastern United States and date from the early Holocene (11700-7000 cal. BP). Gray birch was present in mixed forests in which fires were probably more frequent than today. Only a few sites, located in pine barrens that experienced recurrent fires, show a continuous presence of the species during the middle and late Holocene. Palaeoecological data suggest that the colonization of peatlands by gray birch is a recent phenomenon (20th century), and one unique in peatland history. Anthropic disturbances seem to create conditions that foster this species, which could consequently increase its range in the coming decades. Keywords: Betula populifolia, fires, Holocene, macrofossil analysis, palaeoecology, peatland. Le bouleau gris (Betula populifolia Marshall) est un arbre de debut de succession qui colonise preferentiellement les sols pauvres et secs, de meme que des sites perturbes. Il semble presentement en expansion et on observe qu'il colonise, souvent massivement, certaines tourbieres ombrotrophes. Nous avons examine les donnees des sites ayant fait l'objet d'analyses macrofossiles a l'interieur et a l'exterieur de son aire de repartition continue afin de voir s'il aurait ete plus abondant pendant certaines periodes depuis la deglaciation. C'est pendant l'Holocene inferieur (11700-7000 cal. BP), dans l'est des Etats-Unis, que les macrorestes les plus abondants de l'espece furent trouves. Le bouleau gris etait present au sein de forets mixtes probablement caracterisees par des feux plus frequents qu'aujourd'hui. Seuls quelques sites montrent une presence continue des restes de l'espece pendant l'Holocene moyen et l'Holocene superieur, ces sites se trouvant au sein de landes de pins regies par le feu. Les donnees paleoecologiques suggerent que la colonisation des tourbieres par le bouleau gris est un phenomene recent (20ieme siecle) et unique dans l'histoire des tourbieres. Les perturbations anthropiques semblent creer des conditions propices a cette espece qui pourrait voir son aire de repartition s'agrandir au cours des prochaines decennies. Mots-cles: Betula populifolia, feux, Holocene, analyse macrofossile, paleoecologie, tourbiere., Introduction Gray birch (Betula populifolia Marshall) is a tree species native to eastern North America. As a pioneer, early successional species, it is characterized by rapid growth and a short [...]

Overabundant populations of large herbivores have strong persistent effects on forest composition, structure, and function. However, the mechanism through which plant communities recover their original composition and function after herbivore management remains poorly understood. We assessed the temporal trajectories of the herbaceous communities in Abies balsamea (L.) Mill. and Picea glauca (Moench) Voss stands on Anticosti Island (Quebec, Canada) over 8 years following clear-cutting and deer management. The impact of deer exclusion or reduction to 7.5 and 15 deer x [km.sup.-2] was compared with benchmark in situ deer densities (27 and 56 deer x [km.sup.-2]). Effects of deer management treatments on plant species and functional trait assemblages over time were assessed using principal response curves. Although complete deer exclusion seemed necessary to modify species composition from that occurring under intense browsing, a reduced density of 7.5 deer x [km.sup.-2] was sufficient to induce significant changes in functional trait assemblages of regenerating stands. For instance, reduced deer densities favored plants with brightly colored flowers and compound inflorescences pollinated by animals and producing large seeds and fleshy fruits dispersed by animals. We conclude that the boreal forest's herbaceous communities are resilient to chronic browsing when deer population reduction and forest clearcutting are applied in synergy. Key words: resilience, species composition, functional traits, plant-herbivore interactions, deer. Les populations surabondantes de grands herbivores ont des effets majeurs et persistants sur la composition, la structure et le fonctionnement de la foret. Toutefois, le mecanisme par lequel les communautes vegetales retrouvent leur composition et leur fonctionnement originels en reponse au controle des herbivores demeure mal compris. Nous avons evalue les trajectoires temporelles des communautes herbacees dans des peuplements d'Abies balsamea (L.) Mill. et de Picea glauca (Moench) Voss a l'ile d'Anticosti (Quebec, Canada) pendant 8 annees apres avoir effectue une coupe a blanc et controle les populations de cerfs. L'impact de l'exclusion du cerf ou d'une reduction de la densite a 7,5 ou 15 cerfs x [km.sup.-2] a ete compare a des densites temoins in situ (27 et 56 cerfs x [km.sup.-2]). Les effets des traitements de gestion du cerf sur les especes vegetales et les assemblages de traits fonctionnels ont ete evalues en fonction du temps au moyen de la methode des courbes de reponses principales. Bien que l'exclusion complete du cerf ait semble necessaire pour modifier la composition specifique par rapport a celle observee en conditions de broutage intense, une densite reduite a 7,5 cerfs x [km.sup.-2] etait suffisante pour induire des changements significatifs dans les assemblages de traits fonctionnels des peuplements en regeneration. A titre d'exemple, des densites reduites de cerfs ont favorise les plantes a fleurs de couleur vive et les plantes a fleurs composees pollinisees par les animaux et produisant de grosses graines et des fruits charnus disperses par les animaux. Nous concluons que les communautes herbacees de la foret boreale sont resilientes au broutage chronique quand une reduction des populations de cerfs et une coupe forestiere a blanc sont appliquees en synergie. [Traduit par la Redaction] Mots-cles: resilience, composition specifique, traits fonctionnels, interactions plantes-herbivores, cerf., Introduction Overabundant populations of large herbivores represent a threat to forest ecosystems around the world, overexploiting their habitat to the point of compromising forest regeneration and composition (Cote et al. [...]

Harvesting of medicinal plants from wild populations is increasing worldwide, however, studies on sustainable harvesting techniques are lacking. In this exploratory study, we investigated the impact of leaf harvesting on Rhododendron groenlandicum (Oeder) Kron & Judd, a North American temperate shrub, used traditionally as a medicinal plant by the Cree Nation. The species is widely distributed, but Crees are worried that commercial harvesting could threaten local plant populations. Our study was conducted near the Cree Nation of Mistissini (James Bay, Northern Quebec). Three leaf harvest regimes were tested in 2008 and 2009: no harvest, all leaves harvested, and only old leaves harvested; each treatment was performed on 30 plants. The harvesting of all leaves had a negative impact on stem elongation after the first harvest, while leaf production and stem radial growth decreased after the second harvest. Two-thirds of the plants also died following the second regime of harvesting all leaves. The harvesting of old leaves had no significant impact on growth, leaf production, or survival of R. groenlandicum, even after 2 years of harvest. These results lead to the conclusion that sustainable harvest of this species is possible, but further study is required to make definite recommendations. Key words: conservation, medicinal plant, sustainability, harvesting simulation, Cree Nation. La recolte de plantes medicinales provient surtout de populations sauvages et peu d'etudes existent sur leur durabilite. Nous examinons ici l'impact de la recolte sur Rhododendron groenlandicum (Oeder) Kron & Judd, un arbuste nord americain utilise par la Nation crie pour ses proprietes medicinales. Cette espece est deja recoltee commercialement au Quebec, ce qui pourrait menacer localement certaines populations : cela inquiete d' ailleurs la Nation crie. L'objectif de cette etude etait d' evaluer l' impact de la defoliation sur des plants de R. groenlandicum situees a proximite de Mistissini (Baie James, Quebec). Trois niveaux de recolte de feuilles ont ete appliques sur 30 plants chacun en 2008 et 2009 : aucune recolte, la recolte de toutes les feuilles et la recolte des vieilles feuilles seulement. Les resultats montrent que recolter toutes les feuilles a un impact negatif sur l' elongation des rameaux apres une seule recolte tandis que la croissance radiale et la production de feuilles diminuent apres deux recoltes consecutives. De plus, une mortalite importante des plants (deux tiers) est survenue apres la deuxieme recolte. La recolte des vieilles feuilles seulement n' a pas d' impact significatif sur la croissance et la survie, meme apres la deuxieme annee. Nos resultats indiquent que la recolte de cette plante serait soutenable, cependant d' autres etudes sont necessaires pour emettre des recommandations. Mots-cles : conservation, plantes medicinales, developpement durable, simulation de recolte, Nation crie. [Traduit par la Redaction], Introduction Medicinal plants are gaining popularity in industrial societies as alternative medicine, and their sales are increasing (Cavaliere et al. 2010). This accelerating interest may lead to overharvesting, which in [...]

Linear infrastructures are known to facilitate the spread of undesirable species in ecosystems. Compared with other types of infrastructure, the role of power line rights-of-way (ROWs) as dispersal vectors remains poorly understood, especially with regard to peatlands. The aim of our study was to evaluate their impacts on the vegetation of ombrotrophic (bog) and minerotrophic (fen) peatlands. The vegetation communities within and adjacent to power line ROWs were sampled in 23 bogs and 11 fens in southern Quebec. In fens, invasive species were found in abundance along the first 250 m within ROWs, while native non-peatland species were able to spread into entire ROWs. Invasive species were also able to colonize the adjacent fen habitats but were mostly concentrated in the first 4 m from ROW edges. Some species were, however, able to establish at more than 43 m from ROWs. Invasive and native non-peatland species were mostly restricted to the first 31 m within ROWs intersecting a bog and almost none dispersed in the adjacent bog habitats. Overall, the average cover of native non-peatland and invasive species in ROWs was mostly related to intrinsic abiotic conditions such as water pH, water conductivity, and water table level, while landscape surrounding the peatland and historical variables (e.g., time elapse since the construction of the ROW) had few impacts in both bogs and fens. Key words: corridors, invasive species, edge effect, disturbance, peatland. Les infrastructures lineaires peuvent faciliter la dispersion des especes indesirables. Comparativement aux autres types d'infrastructures, le role des emprises de lignes electriques comme vecteurs de dispersion demeure peu connu, surtout dans les tourbieres. L'objectif de notre etude etait d'evaluer les impacts de ces emprises sur la vegetation des tourbieres ombrotrophes 'bogs' et minerotrophes <>. Nous avons echantillonnela vegetation de 23 emprises de lignes electriques traversant des bogs et de 11 autres traversant des fens, dans le sud du Quebec. Nous avons egalement echantillonne la flore des habitats tourbeux adjacents a ces emprises. Dans les emprises traversant les fens, les especes envahissantes etaient presentes en abondance dans les 250 premiers metres, alors que les especes indigenes non-tourbieres pouvaient se propager dans l'ensemble des emprises. Les especes envahissantes etaient egalement presentes dans les habitats adjacents aux fens, mais surtout dans les quatre premiers metres en bordure des emprises. Certaines de ces especes etaient toutefois encore presentes a plus de 43 metres des emprises. A l'inverse, les especes envahissantes et non-tourbieres etaient surtout confinees le long des 31 premiers metres dans les emprises traversant les bogs et pratiquement aucune n'etait presente dans les habitats adjacents aux bogs. Dans l'ensemble, la susceptibilitedes tourbieres a l'envahissement dans les emprises est surtout liee aux conditions abiotiques des sites comme le pH et la conductivitede l'eau, et le niveau de la nappe phreatique, tandis que le paysage qui entoure les tourbieres et les variables historiques (p. ex., le temps ecouledepuis la construction de l'emprise) ont peu d'effets sur les bogs et les fens. Mots-cles : corridors, especes envahissantes, effet de bordure, perturbation, tourbiere., Introduction Anthropogenic corridors, such as power lines, roads, and trails are common features in urban, suburban, and rural landscapes. Despite their undeniable importance for human activities, the creation and maintenance [...]

Case reports on the discovery and identification of SYNGAP1 mutations which are responsible for autosomal nonsymdromic mental retardation are presented. The identification is very vital as it will help develop pharmacologic treatments for associated complications, and also add to work aimed at improving cognitive functioning.

Abstract: In this study, we reconstructed the long-term fire history of a set of ombrotrophic peatlands (bogs) located in a temperate region of southern Quebec (Bas-Saint-Laurent). Past and recent fire-free [...]