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Phenological transition dictates the seasonal dynamics of ecosystem carbon exchange in a desert steppe
Author(s) -
Huang Gang,
Li Yan
Publication year - 2015
Publication title -
journal of vegetation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 115
eISSN - 1654-1103
pISSN - 1100-9233
DOI - 10.1111/jvs.12236
Subject(s) - ecosystem , phenology , environmental science , perennial plant , biomass (ecology) , steppe , abiotic component , ecosystem respiration , ecology , photosynthetically active radiation , atmospheric sciences , primary production , biology , photosynthesis , botany , geology
Question There are large variations in ecosystem carbon (C) exchange in desert ecosystems; however, few studies have examined the effects of community phenological staging on seasonal variations of ecosystem C exchange. We asked whether factors that control temporal changes in net ecosystem C exchange ( NEE ) vary with an obvious community transition from spring annuals to summer annuals and perennials in a temperate desert steppe. Location South margin of the Gurbantunggute Desert, northwestern China. Methods Ecosystem C and water exchange were measured regularly using closed static chambers and analysed at daily and seasonal intervals. Soil moisture and temperature, photosynthetically active radiation ( PAR ) and plant biomass were also investigated. Results Soil temperature had a dominant influence on C release into the atmosphere from the ecosystem during the snowmelting phase (mid‐March to early April). In the spring annual dominant phase (mid‐April to early June), the diurnal pattern of NEE was consistent with the pattern of PAR . The ecosystem became a weak C resource (0.16 ± 0.03 μmol CO 2 m −2 ·s −1 ) and NEE was positively correlated with community biomass during this phase. In the summer annual and perennial dominant phase (late June to late September), NEE showed relatively large C release (0.74 ± 0.03 μmol CO 2 m −2 ·s −1 ) and was negatively correlated with soil temperature. Conclusion Our results indicate that the primary abiotic factor controlling NEE varies throughout the year, and NEE is determined by the interaction of a plant functional group with precipitation and temperature.