title: Colonization of a Deglaciated Moraine: Contrasting Patterns of Carbon Uptake and Release from C3 and CAM Plants.
abstract: BACKGROUND
  Current glacier retreat makes vast mountain ranges available for vegetation establishment and growth. As a result, carbon (C) is accumulated in the soil, in a negative feedback to climate change. Little is known about the effective C budget of these new ecosystems and how the presence of different vegetation communities influences CO2 fluxes.
  
  
  METHODS
  On the Matsch glacier forefield (Alps, Italy) we measured over two growing seasons the Net Ecosystem Exchange (NEE) of a typical grassland, dominated by the C3 Festuca halleri All., and a community dominated by the CAM rosettes Sempervivum montanum L. Using transparent and opaque chambers, with air temperature as the driver, we partitioned NEE to calculate Ecosystem Respiration (Reco) and Gross Ecosystem Exchange (GEE). In addition, soil and vegetation samples were collected from the same sites to estimate the Net Ecosystem Carbon Balance (NECB).
  
  
  RESULTS
  The two communities showed contrasting GEE but similar Reco patterns, and as a result they were significantly different in NEE during the period measured. The grassland acted as a C sink, with a total cumulated value of -46.4±35.5 g C m-2 NEE, while the plots dominated by the CAM rosettes acted as a source, with 31.9±22.4 g C m-2. In spite of the different NEE, soil analysis did not reveal significant differences in carbon accumulation of the two plant communities (1770±130 for F. halleri and 2080±230 g C m-2 for S. montanum), suggesting that processes often neglected, like lateral flows and winter respiration, can have a similar relevance as NEE in the determination of the Net Ecosystem Carbon Balance.
authors.affiliation: Faculty of Science and Technology, Free University of Bozen/Bolzano, Bolzano, Italy.|Institute of Biology and Chemistry, University of Hildesheim, Hildesheim, Germany.
authors.forename: Elisa
authors.initials: E
authors.lastname: Varolo
authors.affiliation: Faculty of Science and Technology, Free University of Bozen/Bolzano, Bolzano, Italy.
authors.forename: Damiano
authors.initials: D
authors.lastname: Zanotelli
authors.affiliation: Faculty of Science and Technology, Free University of Bozen/Bolzano, Bolzano, Italy.|Forest Services, Autonomous Province of Bolzano, Bolzano, Italy.
authors.forename: Leonardo
authors.identifier: http://orcid.org/0000-0003-2957-9071
authors.initials: L
authors.lastname: Montagnani
authors.affiliation: Faculty of Science and Technology, Free University of Bozen/Bolzano, Bolzano, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Tagliavini
authors.affiliation: Faculty of Science and Technology, Free University of Bozen/Bolzano, Bolzano, Italy.
authors.forename: Stefan
authors.initials: S
authors.lastname: Zerbe
mesh_terms: D001692:Biological Transport; D002244:Carbon / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D057231:Climate Change; D017753:Ecosystem; D046448:Ice Cover / Q000737:chemistry*; D008962:Models, Theoretical; D010788:Photosynthesis; D010944:Plants / Q000378:metabolism*; D012621:Seasons; D013472:Sunlight
chemical_list: D002245:Carbon Dioxide; D002244:Carbon