7 documents found, page 1 of 1
Terpenoid emissions of two mediterranean woody species in response to drought s...
Haberstroh, Simon; Kreuzwieser, Jurgen; Lobo-do-Vale, Raquel; Caldeira, M.C.; Dubbert, Maren; Werner, ChristianeDrought is a major environmental constrain affecting plant performance and survival, particularly in Mediterranean ecosystems. Terpenoids may play a protective role under these conditions, however, observations of drought effects on plant terpenoid emissions are controversial ranging from decreased emissions to unaffected or increased release of terpenoids. In the present study we investigated terpenoid emissio...
Synergy of extreme drought and shrub invasion reduce ecosystem functioning and ...
Caldeira, M.C.; Lecomte, Xavier; David, Teresa S.; Pinto, Joaquim G.; Bugalho, Miguel N.; Werner, ChristianeExtreme drought events and plant invasions are major drivers of global change that can critically affect ecosystem functioning and alter ecosystem-atmosphere exchange. Invaders are expanding worldwide and extreme drought events are projected to increase in frequency and intensity. However, very little is known on how these drivers may interact to affect the functioning and resilience of ecosystems to extreme ev...
Effects of an extremely dry winter on net ecosystem carbon exchange and tree ph...
Costa-e-Silva, Filipe; Correia, Alexandra C.; Piayda, Arndt; Dubbert, Maren; Rebmann, Corinna; Cuntz, Matthias; Werner, Christiane; David, Jorge SoaresIn seasonally dry climates, such as the Mediterranean, lack of rainfall in the usually wet winter may originate severe droughts which are a main cause of inter-annual variation in carbon sequestration. Leaf phenology variability may alter the seasonal pattern of photosynthetic uptake, which in turn is determined by leaf gas exchange limitations. The current study is based on the monitoring of an extremely dry w...
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...