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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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. |
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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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1681057078266822656 |