Higher sensitivity of gross primary productivity than ecosystem respiration to experimental drought and warming across six European shrubland ecosystems

Qiaoyan Li; Albert Tietema; Sabine Reinsch; Inger Kappel Schmidt; Giovanbattista de Dato; Gabriele Guidolotti; Eszter Lellei-Kovács; Gillian Kopittke; Klaus Steenberg Larsen

doi:10.1016/j.scitotenv.2023.165627

Higher sensitivity of gross primary productivity than ecosystem respiration to experimental drought and warming across six European shrubland ecosystems

Sci Total Environ. 2023 Nov 20:900:165627. doi: 10.1016/j.scitotenv.2023.165627. Epub 2023 Jul 24.

Authors

Qiaoyan Li¹, Albert Tietema², Sabine Reinsch³, Inger Kappel Schmidt⁴, Giovanbattista de Dato⁵, Gabriele Guidolotti⁶, Eszter Lellei-Kovács⁷, Gillian Kopittke², Klaus Steenberg Larsen⁴

Affiliations

¹ Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark. Electronic address: qli@ign.ku.dk.
² Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, the Netherlands.
³ UK Centre for Ecology & Hydrology, Environment Centre Wales, Bangor, United Kingdom.
⁴ Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark.
⁵ CREA Council for Agricultural Research and Economics, Research Centre for Forestry and Wood, Arezzo, Italy.
⁶ Research Institute on Terrestrial Ecosystems (IRET), National Research Council (CNR), Porano, TR, Italy.
⁷ Institute of Ecology and Botany, Centre for Ecological Research, Hungary.

PMID: 37495128
DOI: 10.1016/j.scitotenv.2023.165627

Abstract

Shrubland ecosystems across Europe face a range of threats including the potential impacts of climate change. Within the INCREASE project, six shrubland ecosystems along a European climatic gradient were exposed to ecosystem-level year-round experimental nighttime warming and long-term, repeated growing season droughts. We quantified the ecosystem level CO₂ fluxes, i.e. gross primary productivity (GPP), ecosystem respiration (R_eco) and net ecosystem exchange (NEE), in control and treatment plots and compared the treatment effects along the Gaussen aridity index. In general, GPP exhibited higher sensitivity to drought and warming than R_eco and was found to be the dominant contributor to changes in overall NEE. Across the climate gradient, northern sites were more likely to have neutral to positive responses of NEE, i.e. increased CO₂ uptake, to drought and warming partly due to seasonal rewetting. While an earlier investigation across the same sites showed a good cross-site relationship between soil respiration responses to climate over the Gaussen aridity index, the responses of GPP, R_eco and NEE showed a more complex response pattern suggesting that site-specific ecosystem traits, such as different growing season periods and plant species composition, affected the overall response pattern of the ecosystem-level CO₂ fluxes. We found that the observed response patterns of GPP and R_eco rates at the six sites could be explained well by the hypothesized position of each site on site-specific soil moisture response curves of GPP/R_eco fluxes. Such relatively simple, site-specific analyses could help improve our ability to explain observed CO₂ flux patterns in larger meta-analyses as well as in larger-scale model upscaling exercises and thereby help improve our ability to project changes in ecosystem CO₂ fluxes in response to future climate change.

Keywords: Drought; Ecosystem respiration (R(eco)); Gross primary productivity (GPP); Net ecosystem exchange (NEE); Shrubland; Warming.

MeSH terms

Carbon Cycle
Carbon Dioxide / analysis
Droughts*
Ecosystem*
Respiration
Seasons
Soil

Substances

Carbon Dioxide
Soil