Spruce budworm defoliation influences greenhouse gas concentrations in streams
Abstract
One of the most significant natural disturbances in the Canadian boreal and hemiboreal forest is tree defoliation by eastern spruce budworm (SBW), which may increase nutrient and carbon inputs to catchment soils, and in runoff. Closely connected to catchments, headwater streams are known to be significant emitters of greenhouse gases (GHGs); however, how insect defoliation influences stream GHG concentrations remains unknown. To fill this knowledge gap, we measured the carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) concentrations in 12 headwater streams along a gradient of ongoing defoliation in the Gaspé Peninsula, Québec. Streams were sampled 11 times between June and October in 2023 and 2024, and we assessed the role of cumulative defoliation and tree mortality, as well as physical‐chemical, and climatic drivers in explaining GHG variability. We found that CH4 and N2O …
abstract: “One of the most significant natural disturbances in the Canadian boreal and hemiboreal forest is tree defoliation by eastern spruce budworm (SBW), which may increase nutrient and carbon inputs to catchment soils, and in runoff. Closely connected to catchments, headwater streams are known to be significant emitters of greenhouse gases (GHGs); however, how insect defoliation influences stream GHG concentrations remains unknown. To fill this knowledge gap, we measured the carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) concentrations in 12 headwater streams along a gradient of ongoing defoliation in the Gaspé Peninsula, Québec. Streams were sampled 11 times between June and October in 2023 and 2024, and we assessed the role of cumulative defoliation and tree mortality, as well as physical‐chemical, and climatic drivers in explaining GHG variability. We found that CH4 and N2O …” authors:
- Sandrine Ouimet
- E_Emilson
- Michael Stastny
- Lisa Galantini
- Roxane Maranger featured: false projects: [] publication: ‘Journal of Geophysical Research: Biogeosciences’ publication_short: '' publication_types:
- “2” date: ‘2026-02-01T00:00:00Z’ publishDate: ‘2026-04-01’ title: ‘Spruce budworm defoliation influences greenhouse gas concentrations in streams’ url_pdf: “https://agupubs.onlinelibrary.wiley.com/doi/pdfdirect/10.1029/2025JG009152" url_source: “https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2025JG009152"
Erik J.S. Emilson
Research Scientist, Watershed Ecology Team Lead, Associate Editor CJFR
I am interested in how forests support freshwater ecosystem services. My research combines microbial and molecular approaches to undertand how forest productivity and disturbances affect ecosystem functions in headwater streams and lakes.