Guiding principles for rewilding

There has been much recent interest in the concept of rewilding as a tool for nature conservation, but also confusion over the idea, which has limited its utility. We developed a unifying definition and 10 guiding principles for rewilding through a survey of 59 rewilding experts, a summary of key organizations’ rewilding visions, and workshops involving over 100 participants from around the world. The guiding principles convey that rewilding exits on a continuum of scale, connectivity, and level of human influence and aims to restore ecosystem structure and functions to achieve a self-sustaining autonomous nature. These principles clarify the concept of rewilding and improve its effectiveness as a tool to achieve global conservation targets, including those of the UN Decade on Ecosystem Restoration and post-2020 Global Biodiversity Framework. Finally, we suggest differences in rewilding perspectives lie largely in the extent to which it is seen as achievable and in specific interventions. An understanding of the context of rewilding projects is the key to success, and careful site-specific interpretations will help achieve the aims of rewilding.     

On the choice of farm management practices after the reform of the Common Agricultural Policy in 2003

The Common Agricultural Policy (CAP) was fundamentally reformed in 2003. From 2005, farmers will receive decoupled income support payments instead of production premiums if basic standards for environment, food safety, animal health and welfare are met. Farmers are likely to adjust production and management practices to the new policy framework. We describe how this reform fits into the EU strategy of making agricultural production more environmentally friendly by concentrating on the financial aspects of the reforms. Using an agricultural sector model for Austria, we show that the reform will further decrease agricultural outputs, reduce farm inputs, lessen nitrogen surpluses and make environmentally friendly management practices more attractive for farmers.     

Examination of the impact of photoexcited NO2 chemistry on regional air quality

Impact of the excited nitrogen dioxide (NO₂¹) chemistry on air quality in the U.S. is examined using the Community Multiscale Air Quality (CMAQ) model for a summer month. Model simulations were conducted with and without the NO₂¹ chemistry. The largest impact of the NO₂¹ chemistry in the eastern U.S. occurred in the northeast and in the western U.S. occurred in Los Angeles. While the single largest daily maximum 8-h ozone (O₃) increased by 9 ppbv in eastern U.S. and 6 ppbv in western U.S., increases on most days were much lower. No appreciable change in model performance statistics for surface-level O₃ predictions relative to measurements is noted between simulations with and without the NO₂¹ chemistry. Based on model calculations using current estimates of tropospheric emission burden, the NO₂¹ chemistry can increase the monthly mean daytime hydroxyl radicals (OH) and nitrous acid (HONO) by a maximum of 28% and 100 pptv, respectively.     

Energy consumption in the Norwegian fisheries

Energy use is of great concern within fisheries, due to both associated environmental effects and the cost of fuel to fishermen. This article explores the scale of energy consumed by most segments of the Norwegian fishing fleet for gadoid fish and for parts of the pelagic fleet for the period 1980–2005. Fuel use is assigned to the different species caught and different fishing gears using economic and mass-based allocation, where data permit. Correlations between variations in energy use and changing catch rates, quotas and oil prices are found. Inverse correlations are found between fuel consumption per kilogram of fish and catch rates on a yearly basis and between fuel consumption and oil prices on a longer term basis. A long term trend towards increased fuel consumption and reduced real prices is observed from the mid 1980s until 2000. This may indicate that low fuel prices do not motivate the development of energy efficient technology in the long run. Increased fuel use may further be used as an indication of over fishing as the correlation between low catch rates and increased fuel consumption is rather strong. Possible means of reducing energy use and emissions are discussed including changing operational strategies, hull forms and the use of alternative energy carriers. A comparison with measures taken in connection with the previous oil crisis around 1980 is done.     

Ozone and forests in South-Western Europe--What have we learned?

Monitoring of forest condition and ozone (O3) at 83 sites in France, Italy, Luxenbourg, Spain and Switzerland resulted in a number of findings in relation to the knowledge of O3 exposure (concentration and cumulative AOT40), feasibility of the assessment of stomatal O3 flux and relationships between O3 and crown defoliation of beech and visible symptoms on native vegetation. However, the project provides evidence of issues to be addressed within the current monitoring system (data quality, validation sites and response indicators) and indications as to how the monitoring of O3 risk in the context of an effect-oriented monitoring program can be improved.     

Evaluation of the Community Multiscale Air Quality (CMAQ) model version 4.5: Sensitivities impacting model performance: Part I—Ozone

This study examines ozone (O₃) predictions from the Community Multiscale Air Quality (CMAQ) model version 4.5 and discusses potential factors influencing the model results. Daily maximum 8-h average O₃ levels are largely underpredicted when observed O₃ levels are above 85 ppb and overpredicted when they are below 35 ppb. Using a clustering approach, model performance was examined separately for several different synoptic regimes. Under the most common synoptic conditions of a typical summertime Bermuda High setup, the model showed good overall performance for O₃, while associations have been identified here between other, less frequent, synoptic regimes and the O₃ overprediction and underprediction biases. A sensitivity test between the CB-IV and CB05 chemical mechanisms showed that predictions of daily maximum 8-h average O₃ using CB05 were on average 7.3% higher than those using CB-IV. Boundary condition (BC) sensitivity tests show that the overprediction biases at low O₃ levels are more sensitive to the BC O₃ levels near the surface than BC concentrations aloft. These sensitivity tests also show the model performance for O₃ improved when using the global GEOS-CHEM BCs instead of default profiles. Simulations using the newest version of the CMAQ model (v4.6) showed a small improvement in O₃ predictions, particularly when vertical layers were not collapsed. Collectively, the results suggest that key synoptic weather patterns play a leading role in the prediction biases, and more detailed study of these episodes are needed to identify further modeling improvements.     

Relationship between metal speciation in soil solution and metal adsorption at the root surface of ryegrass

The total metal content of the soil or total metal concentration in the soil solution is not always a good indicator for metal availability to plants. Therefore, several speciation techniques have been developed that measure a defined fraction of the total metal concentration in the soil solution. In this study the Donnan Membrane Technique (DMT) was used to measure free metal ion concentrations in CaCl(2) extractions (to mimic the soil solution, and to work under standardized conditions) of 10 different soils, whereas diffusive gradients in thin-films (DGT) and scanning chronopotentiometry (SCP) were used to measure the sum of free and labile metal concentrations in the CaCl(2) extracts. The DGT device was also exposed directly to the (wetted) soil (soil-DGT). The metal concentrations measured with the speciation techniques are related to the metal adsorption at the root surface of ryegrass (Lolium perenne L.), to be able to subsequently predict metal uptake. In most cases the metal adsorption related pH-dependently to the metal concentrations measured by DMT, SCP, and DGT in the CaCl(2) extract. However, the relationship between metal adsorption at the root surface and the metal concentrations measured by the soil-DGT was not-or only slightly-pH dependent. The correlations between metal adsorption at the root surface and metal speciation detected by different speciation techniques allow discussion about rate limiting steps in biouptake and the contribution of metal complexes to metal bioavailability.     

Ozone and forests in South-Western Europe

The paper provides basic information about background, objectives and structure of O3SWE (Ozone at the permanent monitoring plots in South-Western Europe), an international co-operative project aimed at evaluating O3 concentrations, cumulative exposure, uptake and effects on forest vegetation in four countries of South-Western Europe (France, Italy, Luxenbourg, Spain and Switzerland). The project covers a total of 83 permanent plots of the EU and UN/ECE intensive forest monitoring programme and span over three years of investigation (2000-2002). The O3SWE project aims to demonstrate how, using data collected routinely in an intensive forest monitoring network, O3 exposure, flux and effects can be assessed and exceedances critically evaluated.