Impact of agricultural expansion on water footprint in the Amazon under climate change scenarios.

Agricultural expansion and intensification are main drivers of land-use change in Brazil. Soybean is the major crop under expansion in the area. Soybean production involves large amounts of water and fertiliser that act as sources of contamination with potentially negative impacts on adjacent water bodies. These impacts might be intensified by projected climate change in tropical areas. A Water Footprint Assessment (WFA) serves as a tool to assess environmental impacts of water and fertiliser use. The aim of this study was to understand potential impacts on environmental sustainability of agricultural intensification close to a protected forest area of the Amazon under climate change. We carried out a WFA to calculate the water footprint (WF) related to soybean production, Glycine max, to understand the sustainability of the WF in the Tapajós river basin, a region in the Brazilian Amazon with large expansion and intensification of soybean. Based on global datasets, environmental hotspots - potentially unsustainable WF areas - were identified and spatially plotted in both baseline scenario (2010) and projection into 2050 through the use of a land-use change scenario that includes climate change effects. Results show green and grey WF values in 2050 increased by 304% and 268%, respectively. More than one-third of the watersheds doubled their grey WF in 2050. Soybean production in 2010 lies within sustainability limits. However, current soybean expansion and intensification trends lead to large impacts in relation to water pollution and water use, affecting protected areas. Areas not impacted in terms of water pollution dropped by 20.6% in 2050 for the whole catchment, while unsustainability increased 8.1%. Management practices such as water consumption regulations to stimulate efficient water use, reduction of crop water use and evapotranspiration, and optimal fertiliser application control could be key factors in achieving sustainability within a river basin.

An assessment of the impact of climate adaptation measures to reduce flood risk on ecosystem services.

Measures of climate change adaptation often involve modification of land use and land use planning practices. Such changes in land use affect the provision of various ecosystem goods and services. Therefore, it is likely that adaptation measures may result in synergies and trade-offs between a range of ecosystems goods and services. An integrative land use modelling approach is presented to assess such impacts for the European Union. A reference scenario accounts for current trends in global drivers and includes a number of important policy developments that correspond to on-going changes in European policies. The reference scenario is compared to a policy scenario in which a range of measures is implemented to regulate flood risk and protect soils under conditions of climate change. The impacts of the simulated land use dynamics are assessed for four key indicators of ecosystem service provision: flood risk, carbon sequestration, habitat connectivity and biodiversity. The results indicate a large spatial variation in the consequences of the adaptation measures on the provisioning of ecosystem services. Synergies are frequently observed at the location of the measures itself, whereas trade-offs are found at other locations. Reducing land use intensity in specific parts of the catchment may lead to increased pressure in other regions, resulting in trade-offs. Consequently, when aggregating the results to larger spatial scales the positive and negative impacts may be off-set, indicating the need for detailed spatial assessments. The modelled results indicate that for a careful planning and evaluation of adaptation measures it is needed to consider the trade-offs accounting for the negative effects of a measure at locations distant from the actual measure. Integrated land use modelling can help land use planning in such complex trade-off evaluation by providing evidence on synergies and trade-offs between ecosystem services, different policy fields and societal demands.

The growth response of plants to elevated CO2 under non-optimal environmental conditions.

Under benign environmental conditions, plant growth is generally stimulated by elevated atmospheric CO2 concentrations. When environmental conditions become sub- or supra-optimal for growth, changes in the biomass enhancement ratio (BER; total plant biomass at elevated CO2 divided by plant biomass at the current CO2 level) may occur. We analysed literature sources that studied CO2×environment interactions on the growth of herbaceous species and tree seedlings during the vegetative phase. For each experiment we calculated the difference in BER for plants that were grown under 'optimal' and 'non-optimal' conditions. Assuming that interactions would be most apparent if the environmental stress strongly diminished growth, we scaled the difference in the BER values by the growth reduction due to the stress factor. In our compilation we found a large variability in CO2×environment interactions between experiments. To test the impact of experimental design, we simulated a range of analyses with a plant-to-plant variation in size common in experimental plant populations, in combination with a number of replicates generally used in CO2×environment studies. A similar variation in results was found as in the compilation of real experiments, showing the strong impact of stochasticity. We therefore caution against strong inferences derived from single experiments and suggest rather a reliance on average interactions across a range of experiments. Averaged over the literature data available, low soil nutrient supply or sub-optimal temperatures were found to reduce the proportional growth stimulation of elevated CO2. In contrast, BER increased when plants were grown at low water supply, albeit relatively modestly. Reduced irradiance or high salinity caused BER to increase in some cases and decrease in others, resulting in an average interaction with elevated CO2 that was not significant. Under high ozone concentrations, the relative growth enhancement by elevated CO2 was strongly increased, to the extent that high CO2 even compensated in an absolute way for the harmful effect of ozone on growth. No systematic difference in response was found between herbaceous and woody species for any of the environmental variables considered.

Gaseous ammonia counteracts the response of Scots pine needles to elevated atmospheric carbon dioxide.

Four-year-old saplings of Scots pine (Pinus sylvestris L.) were exposed for 8 wk in controlled-environment chambers to charcoal-filtered air (FA), FA supplemented with 754 mg m-3 (650 µl 1-1 )CO2 , FA supplemented with l00 µ m13 NH3 and FA+CO2 +NH3 . Elevated CO2 induced a significant increase in the concentrations of NH4 + and NO3 in the soil solution, while exposure to NH3 enhanced the soil NH4 - concentration. Elevated CO2 significantly increased needle biomass and area, and decreased specific leaf are (SLA) and N concentration in the needle. The activity of peroidase (POD) was decreased, while the activities of glutamine synthetase (GS) and glutamate dehydrogenase (GDH) were only slightly affected. Gaseous NH3 enhanced the concentration of N. soluble proteins and the GS activity in the needless, while it decreased the POD and GDH activities. The effects of elevated CO2 + NH3 on needle biomass production, N Metabolism and POD activity were smaller than the effects of single exposures to elevated CO2 or NH3 . Suggesting that elevated CO2 and NH3 counteract each other and disturb needle physiology. The possible mechanisms underlying the negative interactions of elevated CO2 and NH3 and discussed. The expected stimulation of biomass production by elevated CO2 my be reduced in the presence of atmospheric NH3 .