Extreme drought events have the potential to cause dramatic changes in ecosystem structure and function, but the controls upon ecosystem stability to drought remain poorly understood. Here we used model systems of two commonly occurring, temperate grassland communities to investigate the shortterm interactive effects of a simulated 100-year summer drought event, soil nitrogen (N) availability and plant species diversity (low/high) on key ecosystem processes related to carbon (C) and N cycling. Whole ecosystem CO2 fluxes and leaching losses were recorded during drought and post-rewetting. Litter decomposition and C/N stocks in vegetation, soil and soil microbes were assessed 4 weeks after the end of drought. Experimental drought caused strong reductions in ecosystem respiration and net ecosystem CO2 exchange, but ecosystem fluxes recovered rapidly following rewetting irrespective of N and species diversity. As expected, root C stocks and litter decomposition were adversely affected by drought across all N and plant diversity treatments. In contrast, drought increased soil water retention, organic nutrient leaching losses and soil fertility. Drought responses of above-ground vegetation C stocks varied depending on plant diversity, with greater stability of above-ground vegetation C to drought in the high versus low diversity treatment. This positive effect of high plant diversity on above-ground vegetation C stability coincided with a decrease in the stability of microbial biomass C. Unlike species diversity, soil N availability had limited effects on the stability of ecosystem processes to extreme drought. Overall, our findings indicate that extreme drought events promote post-drought soil nutrient retention and soil fertility, with cascading effects on ecosystem C fixation rates. Data on above-ground ecosystem processes underline the importance of species diversity for grassland function in a changing environment. Furthermore, our results suggest that plant–soil interactions play a key role for the short-term stability of above-ground vegetation C storage to extreme drought events.
Streaming-Dienste galten bisher als neue Antreiber des weltweiten Ausstoßes von CO2. Eine neue Studie im Auftrag des Umweltbundesamtes zeigt jedoch, dass die Auswirkungen aufs Klima geringer sind als befürchtet. <em>Von Christopher Jähnert.</em>
Ex-Umweltminister Klaus Töpfer (CDU) zeigt sich enttäuscht vom Klimapaket der Bundesregierung. Damit könne man die geforderten CO2-Einsparungen bis 2030 niemals erreichen, sagte Töpfer im Dlf. Vielmehr müssten vorhandene Steuern besser dafür genutzt werden. Sie seien zum Teil "klimablind" entstanden.
Der Unterschied zwischen legal und legitim - er könnte in der Auseinandersetzung um die Rodung des Hambacher Walds nicht größer sein, meint Christiane ...
Deutschland ist jedoch weit entfernt von einem solchen Ansatz – vielmehr trägt der Straßenverkehr fast allein die Last, während das übrige Transportwesen, die Industrie, die Gebäude und die Kraftwerke, die Strom erzeugen, kaum Umweltabgaben auf ihre Emissionen zu entrichten haben.
The European Union has been caught trying to undermine any meaningful outcome from the UN climate talks in Paris by instructing its representatives to block discussion of two key mechanisms that could help combat the effects of global warming: the introduction of measures to curb the negative environmental impacts of global trade, and the transfer of technology to help poorer countries in their fight against climate change.
Der Welthandel wächst und bringt Wohlstand. Mit ihm nehmen Emissionen zu: Bis 2050 vervierfacht sich der CO2-Ausstoss durch den internationalen Frachtverkehr, sagt unser Gastautor.
The simulation, which took 75 days to create on a supercomputer at NASA's Goddard Space Flight Center in Greenbelt, Maryland, depicts CO2 emissions from May 2005 to June 2007.
Dank unkonventioneller Fördermethoden könne die Förderung substantiell gesteigert werden, weshalb die CO2-Emission bis 2030 nicht zurückgehen, sondern um mehr als ein Viertel ansteigen werden
This dataset includes U.S. state and national economy-wide emissions of the six major greenhouse gases including CO2, CH4, N2O, and F-Gases (PFCs, HFCs, and SF6) from most major sources and sinks.
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