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Southern Québec (southern + quebec)
Selected AbstractsHow did common ragweed (Ambrosia artemisiifolia L.) spread in Québec?JOURNAL OF BIOGEOGRAPHY, Issue 10 2007A historical analysis using herbarium records Abstract Aim, To reconstruct the spread of common ragweed (Ambrosia artemisiifolia L.; Asteraceae) using herbarium specimens to document whether the habitat preferences of this plant have shifted through time. Location, Southern Québec. Methods, Herbarium specimens stored in the main herbaria of southern Québec were used to reconstruct the spread of common ragweed. All data (sampling location, year of sampling, habitat characteristics, etc.) were incorporated into a geographical information system. Maps indicating the spatial distribution of common ragweed were produced for four time periods. The cumulative number of locations was plotted against time to construct invasion curves. The sequence of habitats where herbarium specimens were collected was also reconstructed. Results, A data base incorporating 707 common ragweed herbarium specimens was constructed for this study. The spread of common ragweed in most regions of southern Québec was initiated at the beginning of the 20th century. Herbarium specimens suggest that common ragweed first spread along river corridors. Specimens of common ragweed were not collected in agricultural fields before the mid-1920s, nor along roads and railways before the mid-1930s. The colonization of a large number of agricultural fields by common ragweed probably began with seed-contaminated crops, but was certainly accelerated by the dispersal of seeds from populations growing along nearby roads. Main conclusions, Herbarium specimens suggest that common ragweed has been present in southern Québec for at least 200 years, but the species was probably restricted to the Montréal area during the 19th century. It is likely that the development of the road network in Québec since the mid-1930s significantly contributed to the spread of common ragweed. Controlling common ragweed solely in agricultural fields would not prevent the re-infestation of crops, because roadsides would act as refuges for the weed. [source] Beyond stratigraphic noise: Unraveling the evolution of stratified assemblages in faunalturbated sitesGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 6 2006Eugène Morin This study explores the stratigraphic evolution of archaeological assemblages in faunalturbated sites. These sites are sometimes described as having limited archaeological value because of varying degrees of occupation mixing. It is argued here that the vertical distribution of assemblages is predictable in faunalturbated contexts. Understanding this vertical evolution may lead to a better assessment of the archaeological potential of a cultural sequence. In faunalturbated soils, the stratigraphic evolution of the assemblages is largely dictated by faunal activity. Tunneling by small animals tend to "sink" cultural remains through the deposits. Although objects sink at a relatively fast pace near the surface, the process slows down as the objects reach the bottom of the biomantle where the sediments are more compact. This process affects the shape of the artifact vertical distribution. The analysis of a multicomponent site from southern Québec is used to model how assemblages may evolve temporally in faunalturbated settings. At Station 3-avant, the stratigraphic distribution of the cultural remains appears to evolve from an upward-skewed distribution to a bottom-skewed distribution through time. This evolution is interpreted to result from the fact that objects are often too large and/or heavy to be moved upward by the pedofauna. In situations in which this stage of stratigraphic evolution is not yet reached, enough information about temporal successions may be retained for the site to be useful for investigating diachronic change. This may prove invaluable in regions in which faunalturbated sequences are common. © 2006 Wiley Periodicals, Inc. [source] Analysis of snow cover variability and change in Québec, 1948,2005HYDROLOGICAL PROCESSES, Issue 14 2010Ross D. Brown Abstract The spatial and temporal characteristics of annual maximum snow water equivalent (SWEmax) and fall and spring snow cover duration (SCD) were analysed over Québec and adjacent area for snow seasons 1948/1949,2004/2005 using reconstructed daily snow depth and SWE. Snow cover variability in Québec was found to be significantly correlated with most of the major atmospheric circulation patterns affecting the climate of eastern North America but the influence was characterized by strong multidecadal-scale variability. The strongest and most consistent relationship was observed between the Pacific Decadal Oscillation (PDO) and fall SCD variability over western Québec. El Niño-Southern Oscillation (ENSO) was found to have a limited impact on Québec snow cover. Evidence was found for a shift in circulation over the study region around 1980 associated with an abrupt increase in sea level pressure (SLP) and decreases in winter precipitation, snow depth and SWE over much of southern Québec, as well as changes in the atmospheric patterns with significant links to snow cover variability. Trend analysis of the reconstructed snow cover over 1948,2005 provided evidence of a clear north,south gradient in SWEmax and spring SCD with significant local decreases over southern Québec and significant local increases over north-central Québec. The increase in SWEmax over northern Québec is consistent with proxy data (lake levels, tree growth forms, permafrost temperatures), with hemispheric-wide trends of increasing precipitation over higher latitudes, and with projections of global climate models (GCMs). Copyright © 2010 Her Majesty the Queen in right of Canada. Published by John Wiley & Sons. Ltd [source] How did common ragweed (Ambrosia artemisiifolia L.) spread in Québec?JOURNAL OF BIOGEOGRAPHY, Issue 10 2007A historical analysis using herbarium records Abstract Aim, To reconstruct the spread of common ragweed (Ambrosia artemisiifolia L.; Asteraceae) using herbarium specimens to document whether the habitat preferences of this plant have shifted through time. Location, Southern Québec. Methods, Herbarium specimens stored in the main herbaria of southern Québec were used to reconstruct the spread of common ragweed. All data (sampling location, year of sampling, habitat characteristics, etc.) were incorporated into a geographical information system. Maps indicating the spatial distribution of common ragweed were produced for four time periods. The cumulative number of locations was plotted against time to construct invasion curves. The sequence of habitats where herbarium specimens were collected was also reconstructed. Results, A data base incorporating 707 common ragweed herbarium specimens was constructed for this study. The spread of common ragweed in most regions of southern Québec was initiated at the beginning of the 20th century. Herbarium specimens suggest that common ragweed first spread along river corridors. Specimens of common ragweed were not collected in agricultural fields before the mid-1920s, nor along roads and railways before the mid-1930s. The colonization of a large number of agricultural fields by common ragweed probably began with seed-contaminated crops, but was certainly accelerated by the dispersal of seeds from populations growing along nearby roads. Main conclusions, Herbarium specimens suggest that common ragweed has been present in southern Québec for at least 200 years, but the species was probably restricted to the Montréal area during the 19th century. It is likely that the development of the road network in Québec since the mid-1930s significantly contributed to the spread of common ragweed. Controlling common ragweed solely in agricultural fields would not prevent the re-infestation of crops, because roadsides would act as refuges for the weed. [source] Diversity of canopy and understorey spiders in north-temperate hardwood forestsAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 2 2009Maxim Larrivée Abstract 1,We characterized and compared diversity patterns of canopy and understorey spiders (Arachnida: Araneae) on sugar maple (Acer saccharum Marsh.) and American beech (Fagus grandifolia Ehrh.) in hardwood forests of southern Québec, Canada. 2,We sampled canopies of 45 sugar maple and 45 American beech trees and associated understorey saplings in mature protected forests near Montréal. Samples were obtained by beating the crown foliage at various heights and by beating saplings around each tree. 3,Eighty-two species were identified from 13 669 individuals. Forty-eight species and 3860 individuals and 72 species and 9809 individuals were collected from the canopy and the understorey, respectively. 4,Multivariate analyses (NMDS ordination and NPMANOVA) showed the composition of canopy and understorey assemblages differed significantly, and canopy assemblages differed between tree species. Rank-abundance distribution models fitted to the canopy and understorey data indicated that different mechanisms structure the assemblages in both habitats. Three abundant spider species were significantly more common in the canopy; ten species were collected significantly more often in the understorey. 5,The forest canopy was shown to be an important reservoir for spider diversity in north-temperate forests. [source] Fluctuations in land values in a rural municipality in southern Québec, CanadaTHE CANADIAN GEOGRAPHER/LE GEOGRAPHE CANADIEN, Issue 4 2006ÉRIK PROVOST The agro-forested region of the Haut-St-Laurent, in southwestern Québec, in Canada, has served as a laboratory for several years to a multi-disciplinary research team seeking to understand the interplay of stakeholders and processes influencing the rural space of southern Québec. Following directly in the footsteps of previous research, this study was undertaken to analyze the hitherto neglected but important aspect of fluctuations in land values with respect to geomorphology and land use, during the 1958,1997 period. A geo-referenced database was built within an object-oriented geographic information system (GIS) that includes data from the sale of parcels of land within the study area, land registry maps, land use maps, and a geomorphological map. These data were analyzed and sorted through queries addressed to the database. Finally, a statistical analysis was performed to analyze the relationship between sale price, geomorphology and indirectly land use, for the entire study period and for each of its decades. The results show that land value has increased at different times during the past, according to its geomorphological type and land use. These relationships are explained by the important transformation phases that have affected southern Québec during the second half of the twentieth century. La région agroforestière du Haut-St-Laurent, dans le sud-ouest du Québec, au Canada, sert de laboratoire depuis plusieurs années à une équipe de recherche multidisciplinaire afin de comprendre le jeu des acteurs et des processus affectant l'espace rural du Sud du Québec. S'inscrivant dans la lignée de ces travaux, cette étude a été entreprise afin d'analyser un aspect important mais négligé jusqu'à maintenant, celui de la fluctuation de la valeur des terres en relation avec la géomorphologie et l'utilisation du sol, durant la période 1958,1997. Une base de données géo-référencées a été créée dans un système d'information géographique (SIG) orienté-objet composée des données provenant des ventes associées aux parcelles composant la région d'étude, des cartes cadastrales, de cartes d'utilisation du sol et d'une carte géomorphologique. Ces données ont été analysées et triées par le biais de requêtes formulées à la base de données. Une analyse statistique multivariée a été réalisée pour analyser la relation entre le prix de vente, la géomorphologie et indirectement l'utilisation du sol pour l'ensemble de la période d'étude et pour chaque décennie. Les résultats montrent que les terres ont connu une hausse de leur valeur à différents moments dans le temps, selon leur type géomorphologique. Cette relation peut être expliquée par les phases importantes de transformation qui ont affecté le Sud du Québec durant la deuxième moitié du XXième siècle. [source] | |||||||||||||