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ARS Home » Plains Area » Temple, Texas » Grassland Soil and Water Research Laboratory » Research » Publications at this Location » Publication #320763
Title: ANPP-precipitation relationships in multi-year drought experiments in natural ecosystems

Author
item ESIARTE, MARC - Consejo Superior De Investigaciones Cientificas (CSIC)
item VICCA, SARA - University Of Antwerp
item PENUELAS, JOSEP - Consejo Superior De Investigaciones Cientificas (CSIC)
item BAHN, MICHAEL - University Of Innsbruck
item BEIER, CLAUS - Norwegian University
item EMMETT, BRIDGET - Centre For Ecology And Hydrology
item Fay, Philip
item HANSON, PAUL - Oak Ridge National Laboratory
item HASIBEDER, ROLAN - University Of Innsbruck
item KIGEL, JAIME - Hebrew University
item KROEL-DULAY, GYORGY - University Of Hungary
item LARSEN, K - University Of Copenhagen
item LELLEI-KOVACS, ESZTER - University Of Hungary
item LIMOUSIN, JEAN - Cemagref(CENTRE FOR AGRICULTURAL AND ENVIRONMENTAL ENGINEERING RESEARCH)
item OGAYA, ROMA - Consejo Superior De Investigaciones Cientificas (CSIC)
item OURCIVAL, JEAN - Cemagref(CENTRE FOR AGRICULTURAL AND ENVIRONMENTAL ENGINEERING RESEARCH)
item SALA, OSVALDO - Arizona State University
item SCHMIDT, INGER - University Of Copenhagen
item STERNBERG, MARCELO - Tel Aviv University
item TIELBORGER, KATJA - Institute Of Plant Nutrition - Germany
item TIETEMA, ALBERT - University Of Amsterdam
item JANSSENS, IVAN - University Of Antwerp

Submitted to: Ecological Society of America Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/2015
Publication Date: 9/3/2015
Citation: Esiarte, M., Vicca, S., Penuelas, J., Bahn, M., Beier, C., Emmett, B.A., Fay, P.A., Hanson, P.J., Hasibeder, R., Kigel, J., Kroel-Dulay, G., Larsen, K.L., Lellei-Kovacs, E., Limousin, J.M., Ogaya, R., Ourcival, J.M., Sala, O.E., Schmidt, I.K., Sternberg, M., Tielborger, K., Tietema, A., Janssens, I. 2015. ANPP-precipitation relationships in multi-year drought experiments in natural ecosystems [abstract]. 100th Annual Meeting of the Ecological Society of America (ESA). August 9-14, 2015. Baltimore, MD. OOS 58-8.

Interpretive Summary:

Technical Abstract: Background/Question/Methods Predicting the effects of a reduction in precipitations on ecosystem productivity confronts an uncertainty: the relationship between aboveground net primary productivity (ANPP) and precipitation differs if the focus is spatial, driven by the climatic mean annual precipitation (MAP) variability among sites, or temporal, driven by the interannual variability in annual precipitation (AP) within sites. In observational studies, the slope of the spatial fit (the ANPP-MAP relationship) is much stronger than the slope of the temporal fit (the ANPP-AP relationship) in most of ecosystems, indicating higher sensitivity to climate versus weather. The spatial fit reflects the variability in ecosystem states and incorporates the long-lasting effects of structural and functional traits that constrain the ANPP of ecosystems. The temporal fits reflect the reversible adjustments in plant physiology and the transient changes in ecosystems structure and functioning that can recover within one or two years. We analyzed results from eleven multi-year (4 or more years) rainfall reduction experiments to determine whether ANPP responded to drying treatments either differently or as expected from the temporal relationship in the non-manipulated treatment. According to the spatial vs temporal framework, we expect that, should the drying treatment induce a response to precipitation different from the responses under the non-manipulated treatment as described by the temporal fit under control conditions, it would be reflected, according to the spatial fit, by a reduction in the intercept of the temporal fit that would indicate a change in the state of the ecosystem. Results/Conclusions Results show that none of the elevenexperiments presented a lower intercept under the drying treatment, providing no evidence for changes in ecosystem state and indicating that, at annual timescale, effects of reducing experimentally the precipitation are not different from the effects of natural variability in precipitation within the AP ranges covered by the experiments. Past manipulation experiments do not unravel the thresholds beyond which temporal fits under non-manipulated conditions are inadequate. Knowing such thresholds will improve the benchmarks for the validation of productivity in carbon cycle models. Therefore, future experiments should include stronger treatments aiming to cross the precipitation thresholds and disrupt the current ANPP-AP relationships. These treatments may be unrealistic in terms of climate change but will display the mechanisms that contribute to regime shifts in ecosystems.