Nouvelle publication | Note scientifique sur les tourbières boréales et leur rôle majeur de puit de carbone | dans la revue Nature | par Joannie Beaulne, Michelle Garneau, Gabriel Magnan et Étienne Boucher de Géographie UQAM et du GÉOTOP | Janvier 2021

Peat deposits store more carbon than trees in forested peatlands of the boreal biome

Joannie Beaulne | Étudiante à la maîtrise | Département de géographie – UQAM – GEOTOP
Michelle Garneau | Professeure | Département de géographie – UQAM – GEOTOP
Gabriel Magnan | Chargé de cours | Département de géographie – UQAM
Étienne Boucher | Professeur | Département de géographie – UQAM – GEOTOP

Scientific Reports 11, Article numéro 2657 | Janvier 2021

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RÉSUMÉ (en anglais seulement)
Peatlands are significant carbon (C) stores, playing a key role in nature-based climate change mitigation. While the effectiveness of non-forested peatlands as C reservoirs is increasingly recognized, the C sequestration function of forested peatlands remains poorly documented, despite their widespread distribution. Here, we evaluate the C sequestration potential of pristine boreal forested peatlands over both recent and millennial timescales. C stock estimates reveal that most of the carbon stored in these ecosystems is found in organic horizons (22.6–66.0 kg m−2), whereas tree C mass (2.8–5.7 kg m−2) decreases with thickening peat. For the first time, we compare the boreal C storage capacities of peat layers and tree biomass on the same timescale, showing that organic horizons (11.0–12.6 kg m−2) can store more carbon than tree aboveground and belowground biomass (2.8–5.7 kg m−2) even over a short time period (last 200 years). We also show that forested peatlands have similar recent rates of C accumulation to boreal non-forested peatlands but lower long-term rates, suggesting higher decay and more important peat layer combustion during fire events. Our findings highlight the significance of forested peatlands for C sequestration and suggest that greater consideration should be given to peat C stores in national greenhouse gas inventories and conservation policies.

Nouvelles publications sur les tourbières du nord du Québec dans le revue scientifique The Holocene| Équipe de Michelle Garneau (Étudiant.e.s et diplômé.e.s) – Géographie et Géotop UQAM | Guillaume Primeau, Mylène Robitaille, Nicole Sanderson et Simon van Bellen

Carbon accumulation in peatlands along a boreal to subarctic transect in eastern Canada

Guillaume Primeau, et Michelle Garneau

Départment de Géographie, Université du Québec à Montréal, Centre de recherche Geotop Canada , et GRIL-UQAM, Université du Québec à Montréal, Canada
Publié en ligne: 17 janvier 2021

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Résumé (en anglais)
In this study, we investigated the links between peat carbon accumulation and past ecological and hydrological conditions in three peatlands (Bouleau, Mista, Auassat) which developed along a South-North transect within a watershed encompassing the boreal and subarctic domain in Eastern Canada. Peatland development and long-term apparent rates of carbon accumulation (LORCA) were asynchronous in the watershed, suggesting an influence of both latitude and topography (altitude) on the length of the growing season (GGD0). Results show that peat initiation within the three peatlands (respectively ca. 9070, 8400, and 6270 cal BP) was delayed after the deglaciation and that LORCA (respectively 35.5, 15.4, and 9.0 g C m−2 yr−1) decreased from South to North. Peatland development and fen to bog transitions were found to be almost synchronous for the two southernmost sites. The fen to bog transition in the northernmost subarctic site was delayed until the 20th century, owing to the less favorable climatic conditions. This suggests that recent warming has extended the length of the growing season and increased Sphagnum growth enough to potentially influence an ecosystem state-shift as observed in other Subarctic regions of eastern Canada.

Long-term and recent ecohydrological dynamics of patterned peatlands in north-central Quebec (Canada)

Auteur.e.s | Mylène RobitailleMichelle GarneauSimon van BellenNicole K. Sanderson

Publié en ligne : 18 janvier 2021

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Résumé (en anglais)
Peatlands are natural ecosystems that provide archives of the hydrological cycle, ecological processes and terrestrial carbon dynamics. In the north-central region of Quebec (eastern Canada), patterned peatlands developed in topographic depressions of the Precambrian Shield following the Laurentide Ice Sheet retreat. These peatlands display characteristics similar to appa mires and other peatlands that developed at the ecotone between the open (taiga) and closed boreal forest biomes of the Northern Hemisphere, and also correspond to the biogeographic limit between ombrotrophic and minerotrophic peatlands. During the Neoglacial cooling period in northeastern Canada, patterned peatlands, mainly oligotrophic fens, registered a hydrological disequilibrium expressed by an increase in surface wetness as aquatic microforms expanded to the detriment of terrestrial surfaces. Ecohydrological trajectories were reconstructed from a detailed study of two patterned peatlands in order to document their sensitivity to climate variations. To do this, plant macrofossil and testate amoeba data were combined with peat carbon accumulation rates, C:N ratios, 210Pb and 14C chronologies. Data show that peatlands initiated ca 6500 cal. y BP as ombrotrophic or minerotrophic systems depending on site-specific conditions, followed by a general increase in surface wetness during the Neoglacial cooling until the end of the Little Ice Age. A relatively synchronous ecosystem state shift from oligotrophic to more ombrotrophic conditions was registered at the beginning of the 20th century in central and lateral cores of both study sites, evoking the likely influence of recent warming on peat accumulation. These results suggest a potential northward migration of the biogeographic limit of the ombrotrophic peatland distribution during the 20th century, which could have implications for the role of these ecosystems as C sinks at the continental scale. Overall, these peatlands have stored a mean carbon mass of ca 100 kg m− 2.

Article scientifique sur les reconstitutions paléohydrologiques des tourbières dans la revue The Holocene| par Gabriel Magnan et Michelle Garneau – Géographie et Géotop UQAM | Janvier 2021

A comparison of Holocene testate amoeba assemblages and paleohydrological records from pollen slides and wet-sieved peat

Gabriel MagnanTerri Lacourse, et Michelle Garneau
Publié:  3 novembre 2020

Volume: 31 issue: 1, page(s): 73-82
Publié en ligne: 3 novembre 2020

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Résumé (en anglais)
In this study, we compared new testate amoeba records produced by the conventional water-based wet-sieving method to testate amoeba data from previous palynological analyses of two Holocene peat profiles from British Columbia, Canada. We used 132 paired samples from the same peat cores to compare the composition of testate amoeba assemblages between the two methods and evaluate the potential of palynological testate amoeba records as quantitative paleohydrological proxies in peatlands. Our results suggest that the palynological treatments (acetolysis, 10% KOH and 150 µm sieving) substantially reduce test concentrations, diversity and richness in most pollen-slide samples. The smaller sieve size used in the palynological treatment (i.e. 150 µm) removed only a small fraction of the total tests, but could introduce a species-specific bias in assemblage composition. However, major shifts between wet and dry conditions, as shown by the water table depth (WTD) reconstructions using wet-sieved samples, were relatively well captured by the palynological datasets in most instances. The palynological assemblages with counts of >50 tests (n = 30) provided WTD estimates similar to those inferred from the wet-sieved samples as the most dominant hydrophilous and xerophilous taxa were relatively well represented in the pollen-slide samples in the two studied peat cores. Testate amoeba data from pollen slides can provide useful paleohydrological information particularly when combined with other paleoenvironmental proxies. Nonetheless, if the goal is to generate quantitative paleohydrological reconstructions, we recommend that testate amoeba analyses be conducted using the wet-sieving method, as testate amoeba concentrations, diversity and richness are typically much lower in samples prepared with palynological treatments.

Recherche collaborative dans le Nord canadien | Récit de recherche par Pénélope Germain Chartrand (Géographie UQAM) et Nia Perron (Université de Montréal) | publié dans Acfas Magazine

Faire de la recherche collaborative dans le Nord canadien

Pénélope Germain Chartrand | Étudiante à la maîtrise – Géographie UQAM
Nia Perron | Étudiante – Université de Montréal

Rubrique : Récits de recherche

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Photographie de Pénélope Germain (Géographie UQAM) Chartrand et Nia Perron (Université de Montréal).

Publication cartographique| Géologie de surface de Palos Park Quadrangle, Cook County, Illinois | Auteurs: Olivier Caron (Géographie, UQAM) et B.B. Curry | 2019

Olivier J. Caron | Professeur invitéGéographie UQAM
B.B. Curry |

Surficial geology of Palos Park Quadrangle, Cook County, Illinois: Illinois State Geological

Illinois State Geological Survey, USGS-STATEMAP
contract report, 2 feuillets
Programme: STATEMAP

Échelle: 1:24 000

Description (en anglais)
Two 35″ x 30″ map sheets; sheet 1 contains map, legends, and 1 figure; sheet 2 includes 2 cross sections and 3 figures, including bedrock surface topography map and sediment thickness map. A brief report is also included on the second map sheet.

Pour en savoir plus, cliquez ici ou sur l’image.

Référence recommandée pour citation:
Caron, O.J. and B.B. Curry, 2019, Surficial geology of Palos Park Quadrangle, Cook County, Illinois: Illinois State Geological Survey, USGS-STATEMAP contract report, 2 sheets, 1:24,000.

Article | Prominent role of volcanism in Common Era climate variability and human history | Dans le revue Dendrochronologia, décembre 2020

À lire aussi | Les volcans et le climat de Pierre-Étienne Caza
ACTUALITÉS UQAM | 3 novembre 2020

Journal Dendrochronologia

Volume 64, Décembre 2020 (125757)


Ulf Büntgen, Dominique Arseneault, Étienne Boucher (Géographie UQAM), Olga V. Churakova, (Sidorova), Fabio Gennaretti, Alan Crivellaro, Malcolm K. Hughes, Alexander V. Kirdyanov, Lara Klippel, Paul J. Krusic, Hans W. Linderholm, Fredrik C. Ljungqvist, Josef Ludescher, Michael McCormick, Vladimir S. Myglan, Kurt Nicolussi, Alma Piermattei, Clive Oppenheimer, Frederick Reinig, Michael Sigl, Eugene A.Vaganov, Jan Esper

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Résumé (en anglais)

Climate reconstructions for the Common Era are compromised by the paucity of annually-resolved and absolutely-dated proxy records prior to medieval times. Where reconstructions are based on combinations of different climate archive types (of varying spatiotemporal resolution, dating uncertainty, record length and predictive skill), it is challenging to estimate past amplitude ranges, disentangle the relative roles of natural and anthropogenic forcing, or probe deeper interrelationships between climate variability and human history. Here, we compile and analyse updated versions of all the existing summer temperature sensitive tree-ring width chronologies from the Northern Hemisphere that span the entire Common Era. We apply a novel ensemble approach to reconstruct extra-tropical summer temperatures from 1 to 2010 CE, and calculate uncertainties at continental to hemispheric scales. Peak warming in the 280s, 990s and 1020s, when volcanic forcing was low, was comparable to modern conditions until 2010 CE. The lowest June–August temperature anomaly in 536 not only marks the beginning of the coldest decade, but also defines the onset of the Late Antique Little Ice Age (LALIA). While prolonged warmth during Roman and medieval times roughly coincides with the tendency towards societal prosperity across much of the North Atlantic/European sector and East Asia, major episodes of volcanically-forced summer cooling often presaged widespread famines, plague outbreaks and political upheavals. Our study reveals a larger amplitude of spatially synchronized summer temperature variation during the first millennium of the Common Era than previously recognised.

Dossier spécial – Covid-19 | Revue Organisations & Territoires | Juin 2020

Dossier spéciale de la revue Organisations & Territoires
Volume 29, numéro 2 | 30 juin 2020

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Dossier spécial – Covid-19 | Contenu

Notes d’actualité

Les suites de la pandémie devront être faites d’innovations territoriales | 149-150
Yannick Hémond (Géographie, UQAM)

Soutenir l’innovation sociale pour construire une société soucieuse du bien commun | 151-153
Réseau québécois en innovation sociale (RQIS)

Philanthropie à portée territorialisée en situation pandémique | 155-157
Jean-Marc Fontan

Le télétravail et le cotravail (coworking) : enjeux socioterritoriaux dans la foulée de la pandémie de COVID-19 | 159-162
Diane-Gabrielle Tremblay

Réactions à la pandémie de la COVID-19 dans les communautés aborigènes de la régions des Kimberley en Australie-Occidentale | 163-170
Melissa Marshall, Sandra Wooltorton, Kate Golson, Anna Dwyer, Gillian Kennedy, Uweinna Albert, Maria Morgan, Laurie Guimond, Anne Poelina, Patrick Sullivan

Espace libre

La pandémie de COVID-19 et le débat sur l’étalement urbain : tournant majeur ou accident de parcours? | 175-183
Martin Simard

La participation sociale dans une communauté rurale au Québec : ce qui la facilité, selon les poins de vue de personnes engagées | 185-196
Marc-André Bonneau, Sophie Dupéré

Enseigner l’entrepreneuriat autrement : l’approche du Startup Weekend | 197-204
Julie Delisle

Dossier spécial | L’ innovation territoriale : Développer, aménager, agir | Revue Organisations & Territoires | 2020

Dossier spéciale de la revue Organisations & Territoires
Volume 29, numéro 2 | 30 juin 2020

Sous la direction de Mélanie Doyon, Juan-Luis Klein, Laurie Guimond, Sylvain Lefebvre | Département de géographie de l’UQAM

Ce dossier spécial a été préparé en marge du Colloque Journée Planification territoriale et développement local: Regards croisés qui s’est tenu à l’UQAM le 30 janvier 2020.

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Table des matières

Éditorial | Jeanne Simard

Présentation « Dossier spécial »
L’ innovation territoriale : Développer, aménager, agir
Mélanie Doyon, Juan-Luis Klein, Laurie Guimond, Sylvain Lefebvre

Dossier spécial
Laboratoires vivants en innovation sociale et coconstruction des connaissances dans les villes : les cas du TIESS (Montréal) et de l’OBISF (Florianópolis) | 1-13
Thiago Magalhaes, Annie Camus, Carolina Andion, Sonia Tello-Rozas

Faire le point sur l’urbanisme tactique : entre innovations et dérives dans la fabrique de la ville | 15-23
Sylvain Lefebvre, Jérémy Diaz, Jean-Marc Adjizian

L’ urbanisme transitoire à Montréal : entre innovation et préservation | 25-39
Taïka Baillargeon, Jérémy Diaz

Cohabitation et espace de rencontre comme moteurs de la nouvelle ruralité au Québec | 41-53
Laurie Guimond, Myriam Simard, Anne Gilbert

Le coworking en région au Québec : une innovation territoriale et entrepreneuriale contribuant au développement local? | 55-67
Diane-Gabrielle Tremblay, Erwan Vaineau

L’ atelier des étudiants. L’innovation sociale en milieu autochtone : le cas de l’Institut Tshakapesh, vecteur de territorialités plurielles | 69-80
David Dufour

Revitalisation urbaine et gentrification positive : le cas du Cinéma Beaubien à Rosemont | 81-92
Wilfredo Angulo, Juan-Luis Klein, Diane-Gabrielle Tremblay

Aider les aidants : quel espace pour l’innovation sociale dans le soutien aux proches aidants en région? | 81-92
Marco Alberio

La sécurisation alimentaire en milieu rural : le cas de trois initiatives agricoles innovantes | 105-115
Mélanie Doyon, Jessica Élie-Leonard, Camille Arsenault-Hétu

Des collectivités résilientes en contexte politique difficile : la contribution de l’intervention collective | 117-126
René Lachapelle, Denis Bourque

Gestion des catastrophes naturelles en sol québécois : rendre socialement et écologiquement responsables les processus de développement des territoires affligés | 127-139
Diane Alalouf-Hall, Jean-Marc Fontan


Vincent van Schendel. Directeur général de l’organisme Territoires innovants en économie sociale et solidaire (TIESS) | 141-148
Mélanie Doyon, Juan-Luis Klein

Anne Marie Aubert. Coordonnatrice au Conseil du système alimentaire montréalais | 171-174
Mélanie Doyon

Article | Ecoagricultural landscapes in the dieng mountains of central Java; A study of their evolution and dynamics | auteurs: Louis Tanguay et Stéphane Bernard | Journal of Rural Studies | 2020

Auteurs: Louis Tanguay (Biologie, UQAM) et Stéphane Bernard (Géographie, UQAM)

Journal of Rural Studies | Volume 77 | Pages 169-184
Juillet 2020

En savoir plus | Accéder à l’article sur la page de JORS

Résumé (anglais)

Arable lands and biodiversity hotspots overlap in many places, resulting in conflicts between actors involved in agricultural development and those promoting biodiversity conservation. In Java, high population density complexifies these conflicts. The challenge for local agricultural systems is to provide for adequate means to meet the food needs of the increasing population while the intensifying urbanization exerts pressure on agrosystems and the remaining natural ecosystems. In this context, this article seeks to evaluate to which extent rural communities and natural biodiversity can cohabit harmoniously within Javanese landscapes. To this end, interviews were conducted with farmers living within three different landscapes located in the Dieng Mountains of Central Java. Visual assessments of the agricultural environment were also carried out. The ecoagriculture approach framework, which integrates the objectives of agricultural development, biodiversity conservation and social development while promoting appropriate governance, was used for the analysis.

All three landscapes exhibit somewhat harmonious relationships between communities, agricultural systems and the surrounding ecosystems, but to different extends. Vegetable crops are relatively beneficial as a result of their high market value and their nutritional qualities, but they also generate more agricultural pollution when compared to agroforestry systems. These latter provide substantial incomes, require less care and help preserve several essential ecosystem services. However, the institutional capacity sustaining the three studied landscapes is considerably defective and represents their main handicap. Even though this case study is specific to Java, it represents a key example of the evolution of ecoagricultural landscapes in a context of high population density. Indeed, the study shows that natural and semi-natural areas responsible for essential ecosystem services can thrive in tropical regions with very high population density. This study also shows that Javanese ecoagricultural landscapes can still act as a sanctuary for the island’s remaining biodiversity, and outside of officially protected areas and of the conflicts that they can generate. Finally, the study shows that agriculture remains a highly important security net for Javanese rural households, and even in a time when the income of these households is becoming more and more diversified. But the fate of the studied landscapes remains uncertain in a globalizing world facing an environmental crisis. Closer collaboration between governmental institutions and local communities might be necessary to insure the preservation of such landscapes.

Faculté des sciences humaines de l’UQAM

Incontournable du domaine des sciences humaines et sociales, la Faculté des sciences humaines de l’UQAM propose des programmes d’études solidement ancrés tant sur le plan théorique qu’empirique. Elle offre un milieu universitaire dynamique, stimulant et inclusif propice à la réalisation de recherches novatrices, à la liberté intellectuelle et à la démocratisation des savoirs.



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