Personne :
Mazerolle, Marc J.

En cours de chargement...
Photo de profil
Adresse électronique
Date de naissance
Projets de recherche
Structures organisationnelles
Fonction
Nom de famille
Mazerolle
Prénom
Marc J.
Affiliation
Université Laval. Département des sciences du bois et de la forêt
ISNI
Identifiant Canadiana
ncf10426444
person.page.name

Résultats de recherche

Voici les éléments 1 - 3 sur 3
  • Publication
    Accès libre
    Response of wild bee communities to beekeeping, urbanization, and flower availability
    (SpringerLink, 2019-11-09) McCune, Frédéric; Normandin-Leclerc, Étienne; Mazerolle, Marc J.; Fournier, Valérie
    Wild bees provide pollination services and are currently declining at the global scale. A potential cause for this decline is competitive interactions with domestic honey bees. Urban beekeeping, a fairly new activity, is rapidly gaining popularity. In contrast with agricultural and natural areas, the extent of competition between honey bees and wild bees in urban areas is unclear. The objectives of this study were to quantify the impact of honey bees, urbanization, and the availability of floral resources on wild bee communities. We hypothesized that honey bees exert negative impacts on wild bees, that floral resources favor wild bee communities and mitigate the negative impacts of competition with honey bees, and that the influence of heat islands, used as a proxy for urbanization, varies between wild bees with their functional traits (nesting behavior). We tested these hypotheses with a data set of 19,077 wild bee specimens collected using colored pan-traps at 25 urban sites in 2012 and 2013. We investigated community and population patterns after accounting for imperfect detection probability. We found no evidence of competition between wild and domesticated bees. Our analyses indicate mixed effects of urban heat islands across species and positive effects of floral resources. We conclude that cities can allow the coexistence of urban beekeeping and wild bees under moderate hive densities. However, it will remain crucial to further investigate the competitive interactions between wild and honey bees to determine the threshold of hive densities beyond which competition could occur.
  • Publication
    Accès libre
    Mouvements et reproduction des amphibiens en tourbières perturbées
    (2004) Mazerolle, Marc J.; Desrochers, André; Rochefort, Line
    Les déclins de populations d'amphibiens ont généré de nombreux travaux sur les effets de la perte d'habitats variés, mais peu en milieux naturellement acides. Néanmoins, plusieurs tourbières du sud-est canadien sont perturbées par l'extraction de la tourbe. Dans le premier chapitre, j'ai comparé l'utilisation des milieux tourbeux par les amphibiens à celle des milieux non tourbeux. Dans les quatre chapitres subséquents, j'ai quantifié les effets de l'extraction de la tourbe sur l'utilisation des étangs de tourbières par les amphibiens et mesuré les contraintes liées à leurs déplacements sur des surfaces exploitées. Les résultats indiquent que les amphibiens utilisent les tourbières surtout comme sites d'estivage. De plus, l'intensité de l'exploitation influence la fréquentation des étangs, mais la quantité et la proximité d'habitats complémentaires (i.e., étangs adjacents, forêt) semblent réduire ces effets. Finalement, les surfaces arides associées à certaines activités anthropiques telles que l'exploitation des tourbières ou l'agriculture, entravent les déplacements des grenouilles, bien que ces effets puissent être atténués par la présence de canaux de drainage.
  • Publication
    Accès libre
    Variation in wood quality in white spruce (Picea glauca (Moench) Voss). Part I. Defining the juvenile–mature wood transition based on tracheid length
    (MDPI, 2015-01-08) Mvolo, Cyriac Serge; Koubaa, Ahmed; Beaulieu, Jean; Cloutier, Alain; Mazerolle, Marc J.
    Estimations of transition age (TA) and juvenile wood proportion (JWP) are important for wood industries due to their impact on end-product quality. However, the relationships between analytical determination of TA based on tracheid length (TL) and recognized thresholds for adequate end products have not yet been established. In this study, we used three different statistical models to estimate TA in white spruce (Picea glauca (Moench) Voss) based on TL radial variation. We compared the results with technological maturity. A two-millimeter threshold, previously suggested for good paper tear strength, was used. Tracheid length increased from pith to bark and from breast height to upper height. Juvenile wood (JW) was conical with the three models. At breast height, TA ranged from 11 to 27 years and JWP ranged from 15.3% to 47.5% across the three models. The linear mixed model produced more conservative estimates than the maximum-quadratic-linear (M_Q_L) model. Both the linear mixed model and the M_Q_L model produced more conservative TA estimates than the piecewise model. TA estimates by the MIXED model, and to a lesser extent by the M_Q_L model, were equivalent to those for real mature wood, whereas TA estimates by the piecewise model were considerably lower, falling into the transition wood area.