7 documents found, page 1 of 1
Species-specific adaptations explain resilience of herbaceous understorey to in...
Jongen, Marjan; Hellmann, Christine; Unger, StephanTo date, the implications of the predicted greater intra-annual variability and extremes in precipitation on ecosystem functioning have received little attention. This study presents results on leaf-level physiological responses of five species covering the functional groups grasses, forbs, and legumes in the understorey of a Mediterranean oak woodland, with increasing precipitation variability, without alterin...
Resilience of montado understorey to experimental precipitation variability fai...
Jongen, Marjan; Unger, Stephan; Fangueiro, David; Cerasoli, Sofia; Silva, João M.N.; Pereira, J.S.tFuture climate scenarios for the Iberian Peninsula predict increasingly variable precipitation regimes,challenging key ecosystem processes in the Mediterranean biome. This study presents a large-scale watermanipulation experiment, exposing the understorey vegetation in a Mediterranean oak woodland to sim-ulations of precipitation variability. We hypothesized that, with no net changes in rainfall quantity, larg...
The impact of changes in the timing of precipitation on the herbaceous understo...
Jongen, Marjan; Lecomte, Xavier; Unger, Stephan; Pintó-Marijuan, Marta; Pereira, J.S.Climate change scenarios for the Iberian Peninsula predict increasing temperatures and increasingly variable precipitation regimes, which will challenge the sustainability and biodiversity of Mediterranean ecosystems such as the semi-natural evergreen oak woodlands. To assess the effects of precipitation variability on productivity, species composition and vegetation gas exchange of the understorey vegetation i...
Interpreting post-drought rewetting effects on soil and ecosystem carbon dynami...
Unger, Stephan; Máguas, Cristina; Pereira, João Santos; David, Teresa S.; Werner, ChristianeA transient increase in soil carbon dioxide efflux after rewetting of previously dry soils, termed the Birch effect, can significantly influence the ecosystem carbon balance. This has generally been related to increased soil microbial respiration in response to a temporal increase in labile soil carbon. In order to quantify ecosystem carbon losses by the Birch effect and to trace the underlying biogeochemical p...
Disentangling drought-induced variation in ecosystem and soil respiration using...
Unger, Stephan; Máguas, Cristina; Pereira, João S.; Aires, Luis M.; David, Teresa S.; Werner, ChristianeCombining C flux measurements with information on their isotopic composition can yield a process-based understanding of ecosystem C dynamics. We studied the variations in both respiratory fluxes and their stable C isotopic compositions (δ13C) for all major components (trees, understory, roots and soil microorganisms) in a Mediterranean oak savannah during a period with increasing drought. We found large drought...
Partitioning carbon fluxes in a Mediterranean oak forest to disentangle changes...
Unger, Stephan; Máguas, Cristina; Pereira, João S.; M. Aires, Luis; S. David, Teresa; Werner, Christiane; Igreja Aires, Luis MiguelNet carbon flux partitioning was used to disentangle abiotic and biotic drivers of all important component fluxes influencing the overall sink strength of a Mediterranean ecosystem during a rapid spring to summer transition. Between May and June 2006 we analyzed how seasonal drought affected ecosystem assimilation and respiration fluxes in an evergreen oak woodland and attributed variations in the component flu...
Partitioning carbon fluxes in a Mediterranean oak forest to disentangle changes...
Unger, Stephan; Máguas, Cristina; Pereira, João Santos; Aires, Luis M.; David, Teresa S.; Werner, ChristianeNet carbon flux partitioning was used to disentangle abiotic and biotic drivers of all important component fluxes influencing the overall sink strength of a Mediterranean ecosystem during a rapid spring to summer transition. Between May and June 2006 we analyzed how seasonal drought affected ecosystem assimilation and respiration fluxes in an evergreen oak woodland and attributed variations in the component flu...