Assessment of nitrogen leaching from arable land in large river basins: Part II: regionalisation using fuzzy rule based modelling

This study deals with fuzzy rule based modelling of nitrogen (N)-leaching from arable land. Main purpose is the elaboration of a method, which allows dynamical regionalisation of results from process-based models for large regions and can be efficiently included in metamodels or decision support systems for rapid integrated assessment of water resources. The paper is the second part of a two-part paper. In the first paper the distributed ecohydrological model SWIM had been applied to calculate and analyse nitrogen dynamics in arable soils for a set of representative natural and management conditions in the Saale River basin (Ecol. Model. (in press)). Here, in the second paper the results from those simulation experiments are used to define, train and validate fuzzy rule systems for the estimation of N-leaching. Nine fuzzy rule systems, specific for nine soil classes, were created from the simulation experiments, representing the conditions for the whole Saale River basin. The fuzzy rule systems operate on monthly time steps and consist of 15 rules and seven input variables each, which are compiled from time series of precipitation, percolation and evapotranspiration as well as from information about fertilizer and crop specific nitrogen uptake. Simulated annealing as a non-linear discrete optimisation method is used for automatic rule assessment. Validation of the fuzzy rule systems, carried out by split sampling of 30-year simulation period, shows satisfactory performance on an annual basis and good performance on the long-term basis with average correlation between SWIM-simulated and fuzzy rule-estimated N-leaching values of 0.78 and 0.94, respectively.     

Effects of bioenergy policies and targets on European wetland restoration options

The EU is committed to combat climate change and to increase security of its energy supply. Bioenergy from forestry and agriculture plays a key role for both. Concurrently, the EU agreed to halt the loss of biodiversity within its member states. To fulfil the biodiversity target more nature conservation and restoration sites need to be designated. There are arising concerns that an increased cultivation of bioenergy crops will decrease the land available for nature reserves and for “traditional” agriculture and forestry. To assess the role of bioenergy in light of possible negative impacts on ecosystems, the European Forest and Agricultural Sector Optimization Model (EUFASOM) assesses simultaneously economic and environmental aspects of land use. This study contributes to the assessment by analyzing the effect of bioenergy production on European wetland allocations by incorporating the spatial wetland distribution model SWEDI into EUFASOM. Results show that bioenergy targets increase land competition and thus marginal costs of wetland preservation but also of food prices. The designation of national wetland conservation targets, on the other hand, stimulates land use intensification in countries without these targets and here only a transfer of environmental stresses takes place. The model is able to illustrate regional differences of results.     

Low Pathogenic Avian Influenza Viruses (H3N8, H5N6): In Vitro Influence of <Emphasis Type="SmallCaps">d</Emphasis>,<Emphasis Type="SmallCaps">l</Emphasis>-Lactic Acid and Sodium Chloride on Infectivity and Virus Persistence in Short Fermented Raw Poultry Sausage

Since highly pathogenic avian influenza virus H5N1 emerged in 1997, avian influenza is considered one of the most important infectious diseases globally. In respect of virus transmission to humans, the consumption of raw poultry products remains of serious concern. In this study, data about survival time and inactivation kinetics of two low pathogenic avian influenza virus (AIV) strains (H3N8, H5N6) in short fermented raw sausage were obtained. In addition, the impact of the preserving factors d,l-lactic acid and sodium chloride on virus infectivity was evaluated through in vitro studies. Virus infectivity was confirmed in embryonated chicken eggs. Inactivation of H3N8 was seen in d,l-lactic acid solutions (0.15 and 0.20%, pH 4.40–4.70 and pH 3.80–3.91) at both temperatures (20 vs. 4°C) during 3 days of exposure. However, infectious virus particles could still be detected after exposure to 0.1% d,l-lactic acid (pH 5.80–5.99). In all NaCl solutions (2, 6 and 12% w/v), infectivity of the H3N8 strain decreased steadily but reduction of the virus titre increased significantly with higher temperature. In raw sausages, decline in virus titre was observed for both strains during ripening and storage. Thereby, decline of virus infectivity was dependent on time and temperature with a more marked effect at higher temperatures (22 vs. 7°C). At refrigeration (7°C), both viruses maintained infectivity over 14 days. Results indicate that appropriate processing of short fermented raw poultry sausage is likely to reduce risk of virus exposure due to adequate inactivation of AIV during ripening and storage.     

Ecological benefits of the alley cropping agroforestry system in sensitive regions of Europe

Alley cropping is an agroforestry system that offers a promising land use alternative for the temperate zone. On the same field, the sustainable production of food and biomass is possible, while simultaneously, especially in marginal areas, the ecological function of the landscape can be improved. Thus, alley cropping corresponds with the increasing demand for renewable energy resources and for a specific adaptation to the predicted changes of climatic conditions within Central Europe.However, presently, little knowledge exists regarding the effects of alley cropping on the environment. In this study a literature survey was undertaken to provide an overview of the different ecological benefits arising from alley cropping systems within temperate Europe. Abiotic factors (nutrient cycle, microclimate), biotic factors (biodiversity) and the effects on the carbon cycle are discussed in detail.Summarising, the results showed that alley cropping may be an ecologically advantageous land use system for sustainable food and biomass production in comparison with conventional agricultural practices. As a very flexible, but low-input system, alley cropping can supply biomass resources in a sustainable way and at the same time provide ecological benefits.     

Sequentielle Schwermetallextraktion aus Staubniederschlägen und Stra\ensedimenten

For the application of our method for the sequential extraction of heavy metals from microsamples presented in part 1 (“Sequentielle Schwermetallextraktion von Mikroproben” — “Sequential Extraction of Heavy Metals from Micro Samples”) an investigation was carried out to evaluate airborne dust fallout and street sediments at two urban sites where different heavy metal immission rates occur due to traffic influence. In the street sediments the total concentrations of zinc, copper and lead was three to fivefold higher in the silt and clay fraction (< 63 μm) than in the particle size fraction (< 1,12 mm), but showed nearly the same mobilisation behaviour. The dust samples showed equal mobilisation behaviour as the street sediments for copper and lead, while zinc was considerably more mobile in the dust samples: In extraction steps I–IV (I: mobile fraction; II: easily deliverable fraction; III: fraction bound to manganese oxides; IV: fraction bound organic to matter) zinc, copper and lead in street sediments, as well as copper and lead in dust samples, were dissolved to 40–70%, whereas about 80% of zinc in the dust samples was already dissolved in extraction step I.     

Memory dynamics and foraging strategies of honeybees

Summary The foraging behavior of a single bee in a patch of four electronic flower dummies (feeders) was studied with the aim of analyzing the informational components in the choice process. In different experimental combinations of reward rates, color marks, odors and distances of the feeders, the behavior of the test bee was monitored by a computer in real time by several devices installed in each feeder. The test bee optimizes by partially matching its choice behavior to the reward rates of the feeders. The matching behavior differs strongly between stay flights (the bee chooses the feeder just visited) and shift flights (the bee chooses one of the three alternative feeders). The probability of stay and shift flights depends on the reward sequence and on the time interval between successive visits. Since functions describing the rising probability of stay flights with rising amounts of sucrose solution just experienced differ for the four feeders, it is concluded that bees develop feeder-specific memories. The choice profiles of shift flights between the three alternative feeders depend on the mean reward rate of the feeder last visited. Good matching is found after visits to the low-reward feeders and poor matching following departure from the high-reward feeders. These results indicate that bees use two different kinds of memories to guide their choice behavior: a transient short-term working memory that is not feeder-specific, and a feeder-specific long-term reference memory. Model calculations were carried out to test this hypothesis. The model was based on a learning rule (the difference rule) developed by Rescorla and Wagner (1972), which was extended to the two forms of memories to predict this operant behavior. The experiments show that a foraging honeybee learns the properties of a food source (its signals and rewards) so effectively that specific expectations guide the choice behavior. Correspondence to: R. Menzel     

Accumulation of orally administered cadmium by the eel (Anguilla anguilla)

Eels were fed on gammarids (Amphipoda: Crustacea) containing high levels of cadmium for 30 days, then the cadmium distribution in the various organs of the fish was investigated. A retention value was calculated for liver + kidney and for whole-body.