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Millennial stocks and fluxes of large woody debris in lakes of the North American taiga

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Gennaretti, Fabio et Arsenault, Dominique et Bégin, Yves (2014). Millennial stocks and fluxes of large woody debris in lakes of the North American taiga. Journal of Ecology, 102 . p. 367-380.

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Résumé

Summary :
1. Large woody debris (LWD) is an important cross-boundary subsidy that enhances the productivity
of lake ecosystems and the stability of aquatic food webs. LWD may also be an important carbon
sink because LWD pieces are preserved for centuries in the littoral zone of lakes and rivers.
However, a long-term analysis of LWD stocks and fluxes in lakes, coupled with the reconstruction
of past disturbances at the site level, has never been attempted.
2. Large woody debris was sampled in five lakes of the Quebec taiga. Actual LWD stocks were
described and residence time of the LWD pieces was established using tree-ring and radiocarbon
dating. LWD losses by decomposition and burial and other factors influencing LWD residence time
were investigated using linear regressions.
3. Impacts of wildfires on LWD fluxes during the last 1400 years were reconstructed separately for
the five lakes using piecewise regression models. Fire years at each site were identified from the
recruitment dates of charred LWD pieces.
4. Large woody debris volume ranged between 0.92 and 1.57 m3 per 100 m of shoreline, and
extrapolating these results to the landscape scale, it was concluded that LWD littoral carbon pools
represent a minimal portion of boreal carbon storage.
5. Large woody debris residence time in boreal lakes was confirmed to be very long. Tree-ring dates
of 1571 LWD pieces, mainly black spruce (Picea mariana (Mill.) BSP.), spanned the last
1400 years, while LWD specimens of older floating chronologies were preserved from decomposition
for up to five millennia. The most influential variables explaining the variation in LWD residence
time were the degree of burial and the distance from the shore.
6. Large woody debris recruitment rates averaged 5.8 pieces per century per 100 m of shoreline.
Fourteen wildfires were the primary cause for changes in the rates of tree establishment in the riparian
forests and of LWD recruitment in the lakes.
7. Synthesis. Interactions between terrestrial and aquatic ecosystems in northern boreal regions are
strongly influenced by wildfires whose effects can last for centuries due to the slow large woody
debris decay rate. Actual LWD stocks and carbon pools are a legacy of the past fire history. -- Keywords : carbon storage ; coarse woody habitat ; cross-boundary subsidy ; dendrochronology ; fire ecology ; land–water interaction ; littoral zone ; palaeoecology and land-use history ; Picea mariana ; Quebec’s boreal forest.

Type de document : Article
Validation par les pairs : Oui
Information complémentaire : Ceci est la version révisée par les pairs de l'article suivant : Gennaretti, F., Arseneault, D. and Bégin, Y. (2014), Millennial stocks and fluxes of large woody debris in lakes of the North American taiga. J Ecol, 102: 367-380., dont la version finale est disponible ici: https://doi.org/10.1111/1365-2745.12198 Cet article peut être utilisé sans visée commerciale, en accord avec les termes et conditions d'utilisation des articles auto-archivés de Wiley. -- This is the peer reviewed version of the following article: Gennaretti, F., Arseneault, D. and Bégin, Y. (2014), Millennial stocks and fluxes of large woody debris in lakes of the North American taiga. J Ecol, 102: 367-380., which has been published in final form at: : https://doi.org/10.1111/1365-2745.12198 This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.
Départements et unités départementales : Département de biologie, chimie et géographie
Déposé par : DIUQAR UQAR
Date de dépôt : 02 oct. 2020 02:06
Dernière modification : 02 oct. 2020 02:12
URI : http://semaphore.uqar.ca/id/eprint/1632

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