Disentangling effects of time since fire, overstory composition and organic layer thickness on nutrient availability in Canadian boreal forest

Wildfire is the primary abiotic disturbance in the boreal forest, and its long-term absence can lead to large changes in ecosystem properties, including the availability and cycling of nutrients. These effects are, however, often confounded with the effects of successional changes in vegetation...

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Main Authors: Cavard, Xavier, Bergeron, Yves, Paré, David, Nilsson, Marie-Charlotte, Wardle, David A.
Other Authors: Asian School of the Environment
Format: Article
Language:English
Published: 2020
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Online Access:https://hdl.handle.net/10356/144071
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-1440712020-10-12T08:33:23Z Disentangling effects of time since fire, overstory composition and organic layer thickness on nutrient availability in Canadian boreal forest Cavard, Xavier Bergeron, Yves Paré, David Nilsson, Marie-Charlotte Wardle, David A. Asian School of the Environment Social sciences::Geography::Environmental sciences Black Spruce Chronosequence Wildfire is the primary abiotic disturbance in the boreal forest, and its long-term absence can lead to large changes in ecosystem properties, including the availability and cycling of nutrients. These effects are, however, often confounded with the effects of successional changes in vegetation toward nutrientconservative species. We studied a system of boreal forested lake islands in eastern Canada, where time since last fire ranged from 50 to 1500 years, and where the relative abundance of the most nutrientconservative tree species, black spruce, was largely independent of time since last fire. This allowed us to disentangle the effects of time since fire and the dominant vegetation on ecosystem properties, including nutrient stocks and concentrations. Effects of time since fire independent of vegetation composition mostly involved an increase in the thickness of the organic layer and in nitrogen concentration in both soil and leaves. Domination by black spruce had strong negative effects on nutrient concentrations andwas associated with a shift towardmore fungi and Gram-positive bacteria in the soil microbial community. Path modeling showed that phosphorus concentration was inversely related to organic layer thickness, which was in turn related to both time since fire and black spruce abundance,whilenitrogen was more directly related to time since fire and the composition of the overstory. We conclude that discriminating between the effects of vegetation and time since fire is necessary for better understanding and predicting the long-term changes that occur in forest nutrient availability and ecosystem properties. This work was financed by Wallenberg Scholars award to DAW, and an NSERC discovery grant to YB. We thank all field assistants that made it possible to collect all this data, as well as the Ministe`re du De´veloppement durable, de l’Environnement et de la Lutte contre les changements climatiques du Que´bec for granting access to protected islands. 2020-10-12T08:33:22Z 2020-10-12T08:33:22Z 2018 Journal Article Cavard, X., Bergeron, Y., Paré, D., Nilsson, M.-C., & Wardle, D. A. (2019). Disentangling effects of time since fire, overstory composition and organic layer thickness on nutrient availability in Canadian boreal forest. Ecosystems, 22(1), 33-48. doi:10.1007/s10021-018-0251-3 1432-9840 https://hdl.handle.net/10356/144071 10.1007/s10021-018-0251-3 1 22 33 48 en Ecosystems © 2018 Springer Science+Business Media, LLC, part of Springer Nature. All rights reserved.
institution Nanyang Technological University
building NTU Library
country Singapore
collection DR-NTU
language English
topic Social sciences::Geography::Environmental sciences
Black Spruce
Chronosequence
spellingShingle Social sciences::Geography::Environmental sciences
Black Spruce
Chronosequence
Cavard, Xavier
Bergeron, Yves
Paré, David
Nilsson, Marie-Charlotte
Wardle, David A.
Disentangling effects of time since fire, overstory composition and organic layer thickness on nutrient availability in Canadian boreal forest
description Wildfire is the primary abiotic disturbance in the boreal forest, and its long-term absence can lead to large changes in ecosystem properties, including the availability and cycling of nutrients. These effects are, however, often confounded with the effects of successional changes in vegetation toward nutrientconservative species. We studied a system of boreal forested lake islands in eastern Canada, where time since last fire ranged from 50 to 1500 years, and where the relative abundance of the most nutrientconservative tree species, black spruce, was largely independent of time since last fire. This allowed us to disentangle the effects of time since fire and the dominant vegetation on ecosystem properties, including nutrient stocks and concentrations. Effects of time since fire independent of vegetation composition mostly involved an increase in the thickness of the organic layer and in nitrogen concentration in both soil and leaves. Domination by black spruce had strong negative effects on nutrient concentrations andwas associated with a shift towardmore fungi and Gram-positive bacteria in the soil microbial community. Path modeling showed that phosphorus concentration was inversely related to organic layer thickness, which was in turn related to both time since fire and black spruce abundance,whilenitrogen was more directly related to time since fire and the composition of the overstory. We conclude that discriminating between the effects of vegetation and time since fire is necessary for better understanding and predicting the long-term changes that occur in forest nutrient availability and ecosystem properties.
author2 Asian School of the Environment
author_facet Asian School of the Environment
Cavard, Xavier
Bergeron, Yves
Paré, David
Nilsson, Marie-Charlotte
Wardle, David A.
format Article
author Cavard, Xavier
Bergeron, Yves
Paré, David
Nilsson, Marie-Charlotte
Wardle, David A.
author_sort Cavard, Xavier
title Disentangling effects of time since fire, overstory composition and organic layer thickness on nutrient availability in Canadian boreal forest
title_short Disentangling effects of time since fire, overstory composition and organic layer thickness on nutrient availability in Canadian boreal forest
title_full Disentangling effects of time since fire, overstory composition and organic layer thickness on nutrient availability in Canadian boreal forest
title_fullStr Disentangling effects of time since fire, overstory composition and organic layer thickness on nutrient availability in Canadian boreal forest
title_full_unstemmed Disentangling effects of time since fire, overstory composition and organic layer thickness on nutrient availability in Canadian boreal forest
title_sort disentangling effects of time since fire, overstory composition and organic layer thickness on nutrient availability in canadian boreal forest
publishDate 2020
url https://hdl.handle.net/10356/144071
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