Paléoécologie de la tourbière du lac Malbaie, dans le massif des Laurentides (Québec) : évaluation du rôle du climat sur l’accumulation de la tourbe

Lavoie, Martin; Richard, Pierre J. H.

doi:10.7202/004843ar

Cited by 18 publications

(12 citation statements)

References 40 publications

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“…2b) and in the reserve is indicative of the change into a different fire regime. The late-Holocene rise in fire frequency observed in the study area is generally consistent with other fire reconstructions in the park based on macro-charcoal (Bussières et al 1996, Lavoie 2001, Zimmermann and Lavoie 2001, and micro-charcoal remains (Lavoie and Richard 2000), as well as regional eastern North American reconstructions based exclusively on microscopic charcoal Richard 2000, Carcaillet et al 2001).…”

Section: Changes In Fire Frequencies Across the Transectsupporting

confidence: 86%

“…Only one distinct charcoal layer was found, which produced a date of 1020 yr BP. The microcharcoal record of the Lac Malbaie peatland, located Ͻ500 m from the site similarly shows a large charcoal peak at 1000 yr BP, possibly being the same fire event (Lavoie and Richard 2000). Single pieces of carbonized needles were found at three other levels in the profile: 23, 40, and 53 cm that correspond with approximate extrapolated dates of 750, 1600, and 2250 yr BP, respectively; no other charcoal pieces were found at these levels.…”

Section: Macrofossil Stratigraphies and Radiocarbon Datesmentioning

confidence: 81%

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The Creation of Alternative Stable States in the Southern Boreal Forest, Québec, Canada

Jasinski

Payette

2005

Ecological Monographs

175

165

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The southernmost spruce–lichen woodlands in the Parc des Grands‐Jardins, Québec, Canada, are situated 500 km south of their usual range in the northern lichen woodland zone. Their co‐occurrence within a spruce–moss forest matrix suggests the existence of alternative stable states. We investigate the possibility of these spruce–lichen woodlands as an alternative stable state along with the factors contributing to their origin and spatiotemporal distribution. Analysis of plant macrofossils, charcoal, head capsules of defoliating insects, and pollen were used along with vegetation surveys to reconstruct the past and present disturbance dynamics along an east–west transect, corresponding to a precipitation and fire frequency gradient. At each site, spruce budworm head capsules were found preceding the charcoal layer delineating the shift to spruce–lichen woodland, demonstrating the compound disturbance (insect–fire) origin of the lichen woodlands. Moss forests previously occupied all lichen woodland sites, with the oldest record starting ca. 8300–9400 yr BP. A change to a higher fire frequency around 2500 yr BP was evident in the lichen woodland zone of the park. A lower fire frequency west of the lichen woodland zone likely is a result of orographic precipitation. While the spruce budworm affects the entire region, lichen woodlands are found exclusively within an increased fire frequency zone. Thus, it is the superimposition of these two disturbance factors that is responsible both for their creation and spatial distribution. Lichen woodland inception dates range between 580 and 1440 yr BP, demonstrating that these lichen woodlands have maintained their open structure with time and have not transformed into closed forests. Their persistence, along with their previous moss forest histories and current occurrence adjacent to closed moss forests, indicate that they are an alternative stable state to the spruce–moss forests and not a successional stage. In contrast to other examples of reported alternative stable states, this one is a result of natural disturbances inherent to the system and not anthropogenic impacts.

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Section: Changes In Fire Frequencies Across the Transectsupporting

confidence: 86%

Section: Macrofossil Stratigraphies and Radiocarbon Datesmentioning

confidence: 81%

The Creation of Alternative Stable States in the Southern Boreal Forest, Québec, Canada

Jasinski

Payette

2005

Ecological Monographs

175

165

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“…Dwarf birch, which is a widespread subarctic species, colonizes the ground layer of the lichen–spruce woodlands in the PGJ (47°30′ N) and the lichen–spruce woodlands situated north of 51° N. The populations of dwarf birch in the PGJ reflect conditions colder than those of today. Widespread occurrence of lichen–spruce woodlands in this area favoured the maintenance of dwarf birch populations in this region for the past several thousand years (Lavoie & Richard, 2000; Jasinski & Payette, 2005). Extreme conditions like summer frosts, water deficiency and low tree density as found in lichen–spruce woodlands create favourable conditions for the expansion and regeneration of dwarf birch.…”

Section: Discussionmentioning

confidence: 99%

Origin of the lichen–spruce woodland in the closed‐crown forest zone of eastern Canada

Girard

Payette

Gagnon

2009

Global Ecology and Biogeography

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Aim We investigate the timing and factors responsible for the transformation of closed-crown forests into lichen-spruce woodlands.Location The study area extends between 70 ° and 72 ° W in the closed-crown forest zone from its southern limit near 47 ° 30 ′ N to its northern limit at the contact with the lichen-spruce woodland zone around 52 ° 10 ′ N. A total of 24 lichen-spruce woodlands were selected.Methods Radiocarbon dating of charcoals at mineral soil contact and within the organic horizons allowed the principal factors causing the degradation of the closedcrown forest to be identified, i.e. light fires, successive fires and the occurrence of a spruce budworm epidemic followed by a fire.Results Charcoals dated in the organic horizon were less than 200 years old, suggesting a recent transformation of the closed-crown forest following surface fires. Before their transformation into lichen-spruce woodlands, stands were occupied by old, dense forests that originated from fires dating back to 1000 yr bp . The radiocarbon dating of charcoals in the organic horizon indicated that several stands burned twice in less than 50 years, while others burned shortly after a spruce budworm epidemic. Light fires are frequent within the lichen-spruce woodlands according to multiple charcoal layers found within the organic matter horizon. Main conclusionsWhile closed-crown forests are predicted to expand under climate warming, compound disturbances diminish the natural regeneration of the closed-crown forests in the south and favour the expansion of lichen-spruce woodlands. As black spruce germinates on mineral soils, surface fires accentuate the expansion of the lichen-spruce woodlands southward. Under global warming, warmer springs will lead to earlier low-intensity fires that do not remove as much organic matter, and hence prevent conditions suitable for black spruce regeneration. Also, spruce budworm reduces seed production for a certain time. The occurrence of fire during this period is critical for regeneration of black spruce.

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“…The gentle slopes of the mineral substrate in this sector (~0.35%) also probably had a positive impact on peatland lateral growth, leading to the coalescence of pre-existing peat basins (Korhola 1994). a BP (Richard 1995;Lavoie & Richard 2000b). a BP.…”

Section: Peatland Complex Initiation and Landscape Successionmentioning

confidence: 99%

Multiproxy analysis of inception and development of the Lac‐à‐la‐Tortue peatland complex, St Lawrence Lowlands, eastern Canada

Pilote

Garneau

Bellen

et al. 2018

Boreas

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The initial conditions for the development of a large peatland complex in the St Lawrence Lowlands were reconstructed to increase the understanding of early development and expansion modes in this region. Peatland basin morphometry was identified by creating a model based on over 1500 existing peat depth measurements, and six cores were extracted along transects from a central (deepest) location towards the margins. C accumulation rates and ecohydrological conditions were reconstructed from plant macrofossils, testate amoeba assemblages and 14 C chronologies. Luminescence dating was performed to better delineate the timing of dune stabilization in the area and potentially related climate changes. Shallow freshwater plant communities acted as nuclei for the development of a rich minerotrophic fen around 10 300 cal. a BP in the deepest part of a shallow depression at the surface of the St-Maurice river delta. Peat inception was followed by the paludification of peripheral parabolic dune systems. Luminescence dating suggested dune stabilization between 11 500 and 10 900 years ago. The initial rich fen persisted until 9500 cal. a BP, and was replaced by a poor fen dominated by sedges as a result of a decrease in mineral nutrient influx from upland runoff. The shift to ombrotrophic conditions in the oldest section of Lac-a-la-Tortue peatland started around 5150 cal. a BP. This major ecohydrological change coincides with those observed in several other peatlands in southern Qu ebec. Variations in carbon and peat accumulation rates in both ombrotrophic and minerotrophic sectors appear to have been primarily controlled by hydroseral succession, peat-forming vegetation, hydrological conditions, topography and fire activity. This study is the first to provide a quantification of the total carbon pool of a peatland complex in southern Qu ebec at 6.39 Mt C, corresponding to a mean C mass per area of 96.9 kg C m À2 (r = 50.60 kg C m À2 ). Louis-MartinPilote (louis-martin.pilote@hotmail.com) and Michelle Garneau, D epartement de g eographie and GEOTOP, Universit e du Qu ebec a Montr eal, Montr eal, QC, Canada; Simonvan Bellen, GEOTOP, Universit e du Qu ebec a Montr eal, Montr eal, QC, Canada; Michel Lamothe, D epartement des sciences de la Terre et de l'atmosph ere, Universit e du Qu ebec a Montr eal, Montr eal, QC, Canada;

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Paléoécologie de la tourbière du lac Malbaie, dans le massif des Laurentides (Québec) : évaluation du rôle du climat sur l’accumulation de la tourbe

Cited by 18 publications

References 40 publications

The Creation of Alternative Stable States in the Southern Boreal Forest, Québec, Canada

The Creation of Alternative Stable States in the Southern Boreal Forest, Québec, Canada

Origin of the lichen–spruce woodland in the closed‐crown forest zone of eastern Canada

Multiproxy analysis of inception and development of the Lac‐à‐la‐Tortue peatland complex, St Lawrence Lowlands, eastern Canada

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