Laurent De Vriendt

Mr. Laurent De Vriendt

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Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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11 October 2018 in Ecosphere
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AKAnders Lorentzen Kolstad
Anders Lorentzen Kolstad
GAGunnar Austrheim
Gunnar Austrheim
ESErling J. Solberg
Erling J. Solberg
LVLaurent De Vriendt
Laurent De Vriendt
JSJames D. M. Speed
James D. M. Speed
Large herbivores can shape young forest stands and determine the successional trajectory of forested ecosystems by selectively browsing palatable species at the sapling stage. Moose (Alces alces) is the dominant vertebrate herbivore in Fennoscandian boreal forests, and high population densities have raised concerns about potential negative effects on ecosystem functioning and properties including biological diversity and timber production. We used 31 herbivore exclosures in Norway to investigate how forests developed after clear‐cutting with or without moose present. We tested how tree demography, abundances of understory plant functional groups, community composition, and plant diversity (including bryophytes) across multiple scales varied with moose exclusion. After seven years, the exclosures were dominated by deciduous trees, including many large rowan (Sorbus aucuparia) individuals, a functionally important keystone species. In contrast, the open plots subject to moose impacts (browsing, trampling, defecation) were dominated by economically important coniferous trees and there was next to no rowan recruitment to taller height classes. The biomass of large herbs and ferns was much greater inside exclosures. This study emphasizes the large immediate effect of moose on early successional boreal forest stands. Landscape‐level alterations caused by reduced deciduous dominance, and a reduction in large flowering herbs is likely to lead to cascading effects on ecosystem functioning. The management of boreal production forests needs to account for the combined effects of silvicultural practices and ungulate herbivory to ensure ecosystem functioning, but this management goal may be jeopardized in our study regions due to drastically reduced abundance of keystone species.

5 September 2020 in Journal of Vegetation Science
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Journal Article
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LVLaurent De Vriendt
Laurent De Vriendt
SLSébastien Lavoie
Sébastien Lavoie
Martin BarretteMartin Barrette
Martin Barrette
JTJean‐Pierre Tremblay
Jean‐Pierre Tremblay

1 October 2012 in American Journal of Botany
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GDGeneviève Dufour‐Tremblay
Geneviève Dufour‐Tremblay
LVLaurent De Vriendt
Laurent De Vriendt
ELEsther Lévesque
Esther Lévesque
SBStéphane Boudreau
Stéphane Boudreau

16 August 2020 in Ecology
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KVKatariina E. M. Vuorinen
Katariina E. M. Vuorinen
AKAnders L. Kolstad
Anders L. Kolstad
LVLaurent De Vriendt
Laurent De Vriendt
GAGunnar Austrheim
Gunnar Austrheim
JTJean‐Pierre Tremblay
Jean‐Pierre Tremblay
JSJames D. M. Speed
James D. M. Speed
Herbivory has potential to modify vegetation responses to climatic changes. However, climate and herbivory also affect each other and rarely work in isolation from other ecological factors, such as plant‐plant competition. Thus, it is challenging to predict the extent to which herbivory can counteract, amplify or interact with climate impacts on ecosystems. Here, we investigate how moose modify climatic responses of boreal trees by using experimental exclosures on two continents and modeling complex causal pathways including several climatic factors, multiple tree species, competition, tree height, time, food availability, and herbivore presence, density and browsing intensity. We show that moose can counteract, i.e. “cool down” positive temperature responses of trees, but that this effect varies between species depending on moose foraging preferences. Growth of preferred deciduous trees was strongly affected by moose, whereas growth of less preferred conifers was mostly driven by climate and tree height. In addition, moose changed temperature responses of rowan in Norway and balsam fir in Canada, by making fir more responsive to temperature but decreasing the strength of the temperature response of rowan. Snow protected trees from browsing, and therefore moose “cooling power” might increase should a warming climate result in decreased snow cover. Furthermore, we found evidence of indirect effects of moose via plant‐plant competition: By constraining growth of competing trees, moose can contribute positively to the growth of other trees. Our study shows that in boreal forests, herbivory cooling power is highly context‐dependent, and in order to understand its potential to prevent changes induced by warming climate, species differences, snow, competition, and climate effects on browsing need to be considered.

1 March 2015 in American Journal of Botany
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MLMarc-André Lemay
Marc-André Lemay
LVLaurent De Vriendt
Laurent De Vriendt
SPStéphanie Pellerin
Stéphanie Pellerin
MPMonique Poulin
Monique Poulin
• Premise of the study: Assessing seed quality in orchids has been hindered by stringent germination requirements. Seed quality has traditionally been assessed in orchids using in vitro or in situ germination protocols or viability staining. However, these methods are not always well suited for rapid assessment of viability in the context of ecological studies.• Methods: The potential of an ex situ protocol for seed viability assessment of orchids in ecological studies was investigated by sowing seeds of Platanthera blephariglottis on Sphagnum moss collected in the orchid's natural habitat. Ex situ germination results were compared with those obtained by viability staining using triphenyltetrazolium chloride (TTC), and the effect of seed testa color on staining and germination results was investigated.• Key results: The ex situ protocol yielded high germination rates, with 66% of the seeds germinating after 9 wk. Depending on the seed testa color class, ex situ germination rates were about 1.4 to 2.5 times higher than viability rates determined using TTC, indicating that the TTC technique underestimated viability compared with the method using ex situ germination. The TTC estimates of viability rates were higher for seeds with dark‐colored testae than for pale ones, whereas seed testa color had no effect on germination.• Conclusions: Our study showed promising results for the use of ex situ germination as an alternative to previously developed protocols for seed viability assessment of orchids in ecological studies. Staining using TTC might not be well suited for this purpose, since it introduced a bias with respect to seed testa color.

28 October 2020 in Forests
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LVLaurent De Vriendt
Laurent De Vriendt
Nelson ThiffaultNelson Thiffault
Nelson Thiffault
ARAlejandro A. Royo
Alejandro A. Royo
Martin BarretteMartin Barrette
Martin Barrette
JTJean-Pierre Tremblay
Jean-Pierre Tremblay
Forest vegetation management can improve planted seedling survival and growth and is thus widely used in plantation silviculture. In some jurisdictions, mechanical release using brushsaws has replaced the traditional use of chemical herbicides for forest vegetation management purposes. However, its associated costs and the increasing difficulty of finding qualified labor represent a challenge. The browsing of competition by large herbivores may represent an alternative to mechanical release when planted seedlings are resistant to browsing. Here, we compare the efficacy of moose browsing relative to mechanical release in controlling competing vegetation and in promoting white spruce growth in plantations. In a high moose density region, we used an experimental design consisting of four pairs of moose exclosures and unfenced plots; fifty percent of both the access-restricted and unrestricted study areas received a mechanical release treatment. Moose browsing was more efficient than mechanical release in diminishing the sapling density and basal area of competing species. Mechanical release only reduced the sapling density of taller competitors (height > 201 cm), whereas browsing reduced the sapling densities of competitors across a greater size range (height > 130 cm). These effects of moose browsing on competition translated into a greater positive effect of moose browsing on the basal area of planted spruces. We attribute the higher effectiveness of moose browsing relative to mechanical release to its chronic nature. Moose browsed continuously throughout the year and for multiple years, whereas mechanical release was applied only one time between the second and fourth years after planting. Our results suggest that pairing wildlife management and silviculture decisions could be in the best interest of both the hunting and forestry industries in regions where plantations are frequent and use browse-resistant crop trees. Favouring browsers in controlling the density of competing species could increase the hunting experience and income, while providing an effective, cost-free, and socially acceptable forest vegetation management service.