University of Oulu

Leffler, A., Beard, K., Kelsey, K., Choi, R., Schmutz, J., Welker, J. (2019) Cloud cover and delayed herbivory relative to timing of spring onset interact to dampen climate change impacts on net ecosystem exchange in a coastal Alaskan wetland, 14 (8), 084030. doi:10.1088/1748-9326/ab1c91

Cloud cover and delayed herbivory relative to timing of spring onset interact to dampen climate change impacts on net ecosystem exchange in a coastal Alaskan wetland

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Author: Leffler, A. Joshua1; Beard, Karen H.2; Kelsey, Katharine C.3;
Organizations: 1Department of Natural Resource Management, South Dakota State, University, Brookings, SD 57006, United States of America
2Department of Wildland Resources, Utah State University and the Ecology Center, Logan, UT 84322-5230, United States of America
3Department of Biological Sciences, University of Alaska-Anchorage, Anchorage, AK 99508, United States of America
4US Geological Survey Alaska Science Center, Anchorage, AK 99508, United States of America
5UArctic, Ecology and Genetics Research Unit, University of Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.8 MB)
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Language: English
Published: IOP Publishing, 2019
Publish Date: 2019-10-07


Rapid warming in northern ecosystems over the past four decades has resulted in earlier spring, increased precipitation, and altered timing of plant–animal interactions, such as herbivory. Advanced spring phenology can lead to longer growing seasons and increased carbon (C) uptake. Greater precipitation coincides with greater cloud cover possibly suppressing photosynthesis. Timing of herbivory relative to spring phenology influences plant biomass. None of these changes are mutually exclusive and their interactions could lead to unexpected consequences for Arctic ecosystem function. We examined the influence of advanced spring phenology, cloud cover, and timing of grazing on C exchange in the Yukon–Kuskokwim Delta of western Alaska for three years. We combined advancement of the growing season using passive-warming open-top chambers (OTC) with controlled timing of goose grazing (early, typical, and late season) and removal of grazing. We also monitored natural variation in incident sunlight to examine the C exchange consequences of these interacting forcings. We monitored net ecosystem exchange of C (NEE) hourly using an autochamber system. Data were used to construct daily light curves for each experimental plot and sunlight data coupled with a clear-sky model was used to quantify daily and seasonal NEE over a range of incident sunlight conditions. Cloudy days resulted in the largest suppression of NEE, reducing C uptake by approximately 2 g C m−2 d−1 regardless of the timing of the season or timing of grazing. Delaying grazing enhanced C uptake by approximately 3 g C m−2 d−1. Advancing spring phenology reduced C uptake by approximately 1.5 g C m−2 d−1, but only when plots were directly warmed by the OTCs; spring advancement did not have a long-term influence on NEE. Consequently, the two strongest drivers of NEE, cloud cover and grazing, can have opposing effects and thus future growing season NEE will depend on the magnitude of change in timing of grazing and incident sunlight.

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Series: Environmental research letters
ISSN: 1748-9318
ISSN-E: 1748-9326
ISSN-L: 1748-9326
Volume: 14
Issue: 8
Article number: 084030
DOI: 10.1088/1748-9326/ab1c91
Type of Publication: A1 Journal article – refereed
Field of Science: 1172 Environmental sciences
Funding: This work was funded by the National Science Foundation (ARC1304523 & ARC1304879) and RC received support from the National Science Foundation under DGE1633756. This research was supported by the South Dakota Agriculture Experiment Station. This research was supported by the Utah Agricultural Experiment Station, Utah State University, and approved as journal paper number 9150.
Copyright information: © 2019 The Author(s). Published by IOP Publishing Ltd. Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.