caa a22 4500 467885397 CHVBK 20180406152732.0 cr unu---uuuuu 170328e20061101xx s 000 0 eng 10.1007/s10021-005-0082-x doi (NATIONALLICENCE)springer-10.1007/s10021-005-0082-x Response of Net Ecosystem Productivity of Three Boreal Forest Stands to Drought [Elektronische Daten] [N. Kljun, T. Black, T. Griffis, A. Barr, D. Gaumont-Guay, K. Morgenstern, J. McCaughey, Z. Nesic] In 2001-03, continuous eddy covariance measurements of carbon dioxide (CO2) flux were made above mature boreal aspen, black spruce, and jack pine forests in Saskatchewan, Canada, prior to and during a 3−year drought. During the 1st drought year, ecosystem respiration (R) was reduced at the aspen site due to the drying of surface soil layers. Gross ecosystem photosynthesis (GEP) increased as a result of a warm spring and a slow decrease of deep soil moisture. These conditions resulted in the highest annual net ecosystem productivity (NEP) in the 9 years of flux measurements at this site. During 2002 and 2003, a reduction of 6% and 34% in NEP, respectively, compared to 2000 was observed as the result of reductions in both R and GEP, indicating a conservative response to the drought. Although the drought affected most of western Canada, there was considerable spatial variability in summer rainfall over the 100−km extent of the study area; summer rainfalls in 2001 and 2002 at the two conifer sites minimized the impact of the drought. In 2003, however, precipitation was similarly low at all three sites. Due to low topographic position and consequent poor drainage at the black spruce site and the coarse soil with low water-holding capacity at the jack pine site almost no reduction in R, GEP, and NEP was observed at these two sites. This study shows that the impact of drought on carbon sequestration by boreal forest ecosystems strongly depends on rainfall distribution, soil characteristics, topography, and the presence of vegetation that is well adapted to these conditions. Springer Science+Business Media, Inc., 2006 boreal forest nationallicence carbon dioxide nationallicence drought nationallicence eddy correlation nationallicence Fluxnet Canada Research Network nationallicence international climate variability nationallicence soil moisture content nationallicence Kljun N. Biometeorology Group, Faculty of Land and Food Systems, University of British Columbia, V6T 1Z4, Vancouver, British Columbia, Canada aut Black T. Biometeorology Group, Faculty of Land and Food Systems, University of British Columbia, V6T 1Z4, Vancouver, British Columbia, Canada aut Griffis T. Department of Soil, Water, and Climate, University of Minnesota, 1991 Upper Buford Circle, 55108, St. Paul, Minnesota, USA aut Barr A. Meteorological Service of Canada, 11 Innovation Blvd., S7N 3H5, Saskatoon, Saskatchewan, Canada aut Gaumont-Guay D. Biometeorology Group, Faculty of Land and Food Systems, University of British Columbia, V6T 1Z4, Vancouver, British Columbia, Canada aut Morgenstern K. Biometeorology Group, Faculty of Land and Food Systems, University of British Columbia, V6T 1Z4, Vancouver, British Columbia, Canada aut McCaughey J. Department of Geography, Queen's University, K7L 3N6, Kingston, Ontario, Canada aut Nesic Z. Biometeorology Group, Faculty of Land and Food Systems, University of British Columbia, V6T 1Z4, Vancouver, British Columbia, Canada aut Ecosystems Springer-Verlag; www.springer-ny.com 9/7(2006-11-01), 1128-1144 1432-9840 9:7<1128 2006 9 10021 https://doi.org/10.1007/s10021-005-0082-x text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10021-005-0082-x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kljun N. Biometeorology Group, Faculty of Land and Food Systems, University of British Columbia, V6T 1Z4, Vancouver, British Columbia, Canada aut NATIONALLICENCE 700 1- Black T. Biometeorology Group, Faculty of Land and Food Systems, University of British Columbia, V6T 1Z4, Vancouver, British Columbia, Canada aut NATIONALLICENCE 700 1- Griffis T. Department of Soil, Water, and Climate, University of Minnesota, 1991 Upper Buford Circle, 55108, St. Paul, Minnesota, USA aut NATIONALLICENCE 700 1- Barr A. Meteorological Service of Canada, 11 Innovation Blvd., S7N 3H5, Saskatoon, Saskatchewan, Canada aut NATIONALLICENCE 700 1- Gaumont-Guay D. Biometeorology Group, Faculty of Land and Food Systems, University of British Columbia, V6T 1Z4, Vancouver, British Columbia, Canada aut NATIONALLICENCE 700 1- Morgenstern K. Biometeorology Group, Faculty of Land and Food Systems, University of British Columbia, V6T 1Z4, Vancouver, British Columbia, Canada aut NATIONALLICENCE 700 1- McCaughey J. Department of Geography, Queen's University, K7L 3N6, Kingston, Ontario, Canada aut NATIONALLICENCE 700 1- Nesic Z. Biometeorology Group, Faculty of Land and Food Systems, University of British Columbia, V6T 1Z4, Vancouver, British Columbia, Canada aut NATIONALLICENCE 773 0- Ecosystems Springer-Verlag; www.springer-ny.com 9/7(2006-11-01), 1128-1144 1432-9840 9:7<1128 2006 9 10021 Metadata rights reserved Springer special CC-BY-NC licence nationallicence SWISSBIB 462653609 BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer