PeichlSonnentagNilsson2014

Référence

Peichl, M., Sonnentag, O. and Nilsson, M.B. (2014) Bringing Color into the Picture: Using Digital Repeat Photography to Investigate Phenology Controls of the Carbon Dioxide Exchange in a Boreal Mire. Ecosystems, 18(1):115-131. (Scopus )

Résumé

Mire vegetation phenology is closely linked to the ecosystem carbon cycle but rarely monitored and quantified with high temporal resolution. In this study, we use digital repeat photography to explore phenology as a control of the carbon dioxide (CO2) exchange measured by eddy covariance (EC) in a minerogenic boreal mire in northern Sweden over 2 years (2011–2012). Strong correlations and seasonal hysteresis effects were observed between the green chromatic coordinate (gcc) derived from the digital image archive and leaf area index, day length, and growing degree-day sum (GDDS). Differences in GDDS between the 2 years were the main control on the between-year variations in the spring patterns of gcc. Periods with lower water table level coincided with an increase of the red chromatic coordinate. The onset and magnitudes of EC-derived photosynthetic CO2 uptake (that is, gross ecosystem production, GEP) and net ecosystem CO2 exchange (NEE) during the spring green-up of vascular plants were more closely related to those of gcc than to those of air temperature and photosynthetically active radiation. In contrast, abiotic variables controlled GEP during the summer period when vascular plant canopy cover was fully developed. Stepwise regression analysis suggested that gcc contributed substantially in explaining variations in GEP during spring and autumn. Over both growing seasons, gcc was well correlated with GEP (r2 = 0.68), NEE (r2 = 0.58), and ecosystem respiration (r2 = 0.50). Overall, we show that digital repeat photography provides an inexpensive and effective method for the continuous quantification of the phenological patterns of the vascular plant community in mire ecosystems. Our results suggest that vegetation phenology is an important control of the mire CO2 exchange and should be considered in both experimental and modeling studies to better account for the separate effects of phenology and abiotic drivers on mire carbon dynamics. © 2014, Springer Science+Business Media New York.

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@ARTICLE { PeichlSonnentagNilsson2014,
    AUTHOR = { Peichl, M. and Sonnentag, O. and Nilsson, M.B. },
    TITLE = { Bringing Color into the Picture: Using Digital Repeat Photography to Investigate Phenology Controls of the Carbon Dioxide Exchange in a Boreal Mire },
    JOURNAL = { Ecosystems },
    YEAR = { 2014 },
    VOLUME = { 18 },
    NUMBER = { 1 },
    PAGES = { 115-131 },
    NOTE = { cited By 21 },
    ABSTRACT = { Mire vegetation phenology is closely linked to the ecosystem carbon cycle but rarely monitored and quantified with high temporal resolution. In this study, we use digital repeat photography to explore phenology as a control of the carbon dioxide (CO2) exchange measured by eddy covariance (EC) in a minerogenic boreal mire in northern Sweden over 2 years (2011–2012). Strong correlations and seasonal hysteresis effects were observed between the green chromatic coordinate (gcc) derived from the digital image archive and leaf area index, day length, and growing degree-day sum (GDDS). Differences in GDDS between the 2 years were the main control on the between-year variations in the spring patterns of gcc. Periods with lower water table level coincided with an increase of the red chromatic coordinate. The onset and magnitudes of EC-derived photosynthetic CO2 uptake (that is, gross ecosystem production, GEP) and net ecosystem CO2 exchange (NEE) during the spring green-up of vascular plants were more closely related to those of gcc than to those of air temperature and photosynthetically active radiation. In contrast, abiotic variables controlled GEP during the summer period when vascular plant canopy cover was fully developed. Stepwise regression analysis suggested that gcc contributed substantially in explaining variations in GEP during spring and autumn. Over both growing seasons, gcc was well correlated with GEP (r2 = 0.68), NEE (r2 = 0.58), and ecosystem respiration (r2 = 0.50). Overall, we show that digital repeat photography provides an inexpensive and effective method for the continuous quantification of the phenological patterns of the vascular plant community in mire ecosystems. Our results suggest that vegetation phenology is an important control of the mire CO2 exchange and should be considered in both experimental and modeling studies to better account for the separate effects of phenology and abiotic drivers on mire carbon dynamics. © 2014, Springer Science+Business Media New York. },
    AFFILIATION = { Department of Forest Ecology and Management, Swedish University of Agricultural Sciences Umeå, Umeå, Sweden; Département de géographie, Université de Montréal, Montreal, QC, Canada },
    AUTHOR_KEYWORDS = { boreal landscape; canopy greenness; carbon cycle; climate; digital repeat photography; eddy covariance; peatland; phenology; RGB chromatic coordinates },
    DOCUMENT_TYPE = { Article },
    DOI = { 10.1007/s10021-014-9815-z },
    SOURCE = { Scopus },
    URL = { https://www.scopus.com/inward/record.uri?eid=2-s2.0-84925533905&doi=10.1007%2fs10021-014-9815-z&partnerID=40&md5=63b5bc6fdcb73ba8ce60d2e561501f2a },
}

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