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New Permian plant specimens are described from Prince Edward Island, Canada. They include attached specimens of leaf and stem genera Walchia and Tylodendron, enabling reconstruction of this Early Permian conifer. Although poorly preserved, the study of these floras extends our knowledge of diversity and climate conditions in the region. By placing these findings in a broader stratigraphic and geographic framework, we can document the phytogeographic and climate trends through the Carboniferous and Permian in the Maritimes Basin. Combined data on temporal trends in climate-sensitive sediments, as well as macrofloral and microfloral diversities, generally match the independently derived paleolatitudinal estimates. These show the region migrating from the southern subtropics across the Equator and into the northern subtropics between the Early Carboniferous and Early Permian. Evaporites and pedogenic carbonates, together with low-diversity floras, match its subtropical position in the Early Carboniferous. In contrast, coals are present in the Late Carboniferous, accompanied by high-diversity macro- and microfloral remains, when the region was on or near the Equator. However, the subsequent transition to pedogenic carbonates, eolian sands, and lower diversity floras is not matched by significant poleward latitudinal motion. We ascribe these changes to a decrease in moisture availability, as transgressions of epeiric seas became less frequent and finally stopped altogether, causing an increase of continentality in Euramerica.Cet article décrit de nouveaux spécimens de plantes datant du Permien, provenant de l'Île-du-Prince-Édouard, Canada. Ils comprennent des spécimens de feuilles et de tiges rattachées de genre Walchia et Tylodendron, permettant la reconstruction de ce conifère du Permien précoce. Bien que ces flores soient mal préservées, leur étude étend nos connaissances de la diversité et des conditions climatiques de la région. En plaçant ces découvertes dans un cadre stratigraphique et géographique plus large, nous pouvons documenter les tendances phytogéographiques et climatiques du Carbonifère et du Permien dans le bassin des Maritimes. Des données combinées sur les tendances temporelles dans des sédiments sensibles au climat et des diversités relatives à la macro- et à la microflore concordent généralement avec les estimations de paléoaltitude dérivées de façon indépendante. Ces données montrent qu'entre le Carbonifère précoce et le Permien précoce, il y eut une migration des régions subtropicales méridionales, par delà l'équateur, vers les régions subtropicales septentrionales. Des évaporites et des carbonates pédogénétiques, avec des flores faiblement diversifiées, correspondent à sa position subtropicale au Carbonifère précoce. Par contre, on retrouve des charbons au Carbonifère tardif, accompagnés de restes de macro- et de microflores grandement diversifiées, lorsque la région était à ou prés de l'équateur. Toutefois, la transition subséquente à des carbonates pédogénétiques, à des sables éoliens et à une diversité florale moindre n'est pas corrélée par un mouvement méridien significatif vers le pôle. Nous attribuons ces changements à une réduction de l'humidité disponible, alors que les transgressions des mers épicontinentales devenaient de moins en moins fréquentes et qu'elles ont finalement cessé tout à fait, causant une augmentation de la continentalité en Euramérique.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

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Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Civil Engineering is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Discusses Holocene vegetation and natural disturbance in the Englemann Spruce-Subalpine Fir (ESSF) biogeoclimatic zone at Mount Kobau, British Columbia. Reconstruction of the vegetation and natural disturbance history of the Mount Kobau area, in the Engelmann spruce (Picea engelmannii Parry ex Engelm.) ? subalpine fir (Abies lasiocarpa (Hook.) Nutt.) ESSF forest, using pollen, plant macrofossils, and microscopic charcoal; Description of Holocene period of rapid warming; Increase of moisture during the mid-Holocene when fires may have occurred more widely and burned more severely; How open lodgepole pine (Pinus contorta Dougl. ex Loud.) parkland occupied the mountain summit; Cooling of the Late-Holocene which resulted in the establishment of modern ESSF forest; Confirmation of a broad three-stage regional climate pattern inferred by the vegetation of the Holocene; Under future anticipated climate change, the high-elevation, dry ESSF forests in southern British Columbia may be replaced by grasslands.

Commercial catches of two ecologically distinct sympatric smelt (Osmerus mordax) populations segregated along the two shores of the St. Lawrence middle estuary exhibited inverse patterns with periodicities on the order of 30 years. The influence of water level in the St. Lawrence River and air temperature, chosen to reflect variations in hydrology and climate, differed markedly between the two populations. Analyses revealed that both water level and temperature were generally positively related with north-shore smelt landings and negatively related with south-shore smelt landings. For both populations, a number of significant climatic factors contributing to variance in smelt landings were lagged by one to three years relative to the year of landings, indicating that climatic variables influenced smelt recruitment. The contrasting role of hydroclimatic variables in driving these abundance cycles is likely related to differential exploitation of estuarine habitats; the south-shore population is associated with shallow shoal habitat, whereas the north-shore population is associated with deep channel habitat. The responses of the two smelt populations also reflect the fundamental ecological differences existing between shoal and channel habitats, indicating that future climate change may differentially affect other populations or species that are segregated between these two habitats.Les débarquements commerciaux de deux populations d'éperlans (Osmerus mordax) arc-en-ciel sympatriques, distinctes du point de vue écologique et ségréguées le long des deux rives de l'estuaire moyen du Saint-Laurent, montrent des variations cycliques inverses et une périodicité de l'ordre de 30 ans. L'influence du niveau d'eau du fleuve et de la température de l'air, choisis dans l'étude pour refléter les variations du régime hydrologique et du climat, diffèrent de façon marquée pour les deux populations. Les analyses révèlent que le niveau de l'eau et la température sont généralement corrélés positivement aux débarquements de la rive nord et négativement à ceux de la rive sud. Quelques un des principaux facteurs climatiques contribuant pour une grande part aux variations des débarquements des deux rives étaient décalés dans le temps, indiquant que les facteurs climatiques influencent le recrutement des éperlans. L'effet contrasté des variables hydroclimatiques sur les cycles d'abondance est vraisemblablement liée à l'utilisation différentielle des habitats de l'estuaire; la population de la rive sud est associée à un habitat peu profond et celle de la rive nord est à un chenal profond. Les réponses de ces deux populations d'éperlans reflètent aussi des différences écologiques existant entre des habitats peu profonds et un chenal profond, indiquant que les changements climatiques futurs pourraient avoir des effets différents sur d'autres populations ou d'autres espèces, qui sont ségréguées entre ces deux types d'habitats. [ABSTRACT FROM AUTHOR]