Vascular plant-mediated controls on atmospheric carbon assimilation and peat carbon decomposition under climate change.

Climate change can alter peatland plant community composition by promoting the growth of vascular plants. How such vegetation change affects peatland carbon dynamics remains, however, unclear. In order to assess the effect of vegetation change on carbon uptake and release, we performed a vascular plant-removal experiment in two Sphagnum-dominated peatlands that represent contrasting stages of natural vegetation succession along a climatic gradient.

Tropical soils degraded by slash-and-burn cultivation can be recultivated when amended with ashes and compost.

In many tropical regions, slash-and-burn agriculture is considered as a driver of deforestation; the forest is converted into agricultural land by cutting and burning the trees. However, the fields are abandoned after few years because of yield decrease and weed invasion. Consequently, new surfaces are regularly cleared from the primary forest.

Winter ecology of a subalpine grassland: Effects of snow removal on soil respiration, microbial structure and function.

Seasonal snow cover provides essential insulation for mountain ecosystems, but expected changes in precipitation patterns and snow cover duration due to global warming can influence the activity of soil microbial communities. In turn, these changes have the potential to create new dynamics of soil organic matter cycling. To assess the effects of experimental snow removal and advanced spring conditions on soil carbon (C) and nitrogen (N) dynamics, and on the biomass and structure of soil microbial communities, we performed an in situ study in a subalpine grassland in the Austrian Alps, in conjunction with soil incubations under controlled conditions.

Links between soil microbial communities and plant traits in a species-rich grassland under long-term climate change.

Climate change can influence soil microorganisms directly by altering their growth and activity but also indirectly via effects on the vegetation, which modifies the availability of resources. Direct impacts of climate change on soil microorganisms can occur rapidly, whereas indirect effects mediated by shifts in plant community composition are not immediately apparent and likely to increase over time. We used molecular fingerprinting of bacterial and fungal communities in the soil to investigate the effects of 17 years of temperature and rainfall manipulations in a species-rich grassland near Buxton, UK.

Loss of testate amoeba functional diversity with increasing frost intensity across a continental gradient reduces microbial activity in peatlands.

Soil microbial communities significantly contribute to global fluxes of nutrients and carbon. Their response to climate change, including winter warming, is expected to modify these processes through direct effects on microbial functions due to osmotic stress, and changing temperature regimes. Using four European peatlands reflecting different frequencies of frost events, we show that peatland testate amoeba communities diverge among sites with different winter climates, and that this is reflected through contrasting functions.

An unexpected role for mixotrophs in the response of peatland carbon cycling to climate warming.

Mixotrophic protists are increasingly recognized for their significant contribution to carbon (C) cycling. As phototrophs they contribute to photosynthetic C fixation, whilst as predators of decomposers, they indirectly influence organic matter decomposition. Despite these direct and indirect effects on the C cycle, little is known about the responses of peatland mixotrophs to climate change and the potential consequences for the peatland C cycle.

Evaluation of dissolved organic carbon as a soil quality indicator in national monitoring schemes.

Background: Monitoring the properties of dissolved organic carbon (DOC) in soil water is frequently used to evaluate changes in soil quality and to explain shifts in freshwater ecosystem functioning.

Methods: Using >700 individual soils (0-15 cm) collected from a 209,331 km(2) area we evaluated the relationship between soil classification (7 major soil types) or vegetation cover (8 dominant classes, e.g.

Diminished soil functions occur under simulated climate change in a sup-alpine pasture, but heterotrophic temperature sensitivity indicates microbial resilience.

The pressure of climate change is disproportionately high in mountainous regions, and small changes may push ecosystem processes beyond sensitivity thresholds, creating new dynamics of carbon and nutrient cycling. Given that the rate of organic matter decomposition is strongly dependent upon temperature and soil moisture, the sensitivity of soil respiration to both metrics is highly relevant when considering soil-atmosphere feedbacks under a changing climate. To assess the effects of changing climate in a mountain pasture system, we transplanted turfs along an elevation gradient, monitored in situ soil respiration, incubated collected top-soils to determine legacy effects on temperature sensitivity, and analysed soil organic matter (SOM) to detect changes in quality and quantity of SOM fractions.