Re-Meandering German Lowland Streams: Qualitative and Quantitative Effects of Restoration Measures on Hydromorphology and Macroinvertebrates

We investigated the effects of two river restoration projects on hydromorphology and macroinvertebrate fauna in two German lowland rivers, the Schwalm and the Gartroper Mühlenbach. The stream channels were re-meandered and the floodplain levels were lowered to better connect the streams to their floodplains. The restoration was performed 10 years ago in the Schwalm and 2 years ago in the Gartroper Mühlenbach. We compared the restored reaches to nearby anthropogenically straightened reaches. Twenty-five hydromorphological parameters were recorded on twenty transects; between nine and 23 substrate-specific macroinvertebrate samples were taken per reach. Several hydromorphological parameters, such as the number and width of channel features and the number of substrate types, were significantly higher in the restored reaches compared to nearby anthropogenically straightened reaches. Total numbers of invertebrate families, genera, and taxa were also higher in the restored reaches than in the anthropogenically straightened reaches. Biotic substrates like dead wood or macrophytes were more abundant in the restored reaches, and these substrates hosted 28 taxa not found in the straightened reaches. While diversity was high in both restored reaches, overall abundance increased only in the river that was restored 10 years ago. Using NMS-analysis, substrate-specific faunistic samples of the restored reaches were compared to those of the straightened reaches. Our results revealed different invertebrate communities on the same substrates in the recently restored river. In the 10-year-old restoration, however, the same substrates were similarly inhabited. This comparable colonization of substrates may reflect succession in the macroinvertebrate community. The results are discussed according to the re-colonization potentials of the upstream and downstream reaches and the dispersal capacity of taxa.     

Conceptualising disaster social capital: what it is,why it matters,and how it can be enhanced

Social capital discourse occupies an important place in disaster studies. Scholars have adopted various inflections of social capital to explain how those with greater amounts of this crucial resource are generally more resilient to disasters and experience speedier recovery. Disaster scholars have also discovered that people typically display altruistic tendencies in the wake of disasters and develop novel networks of mutual support, known as ‘communitas’, which is also seen to build resilience and boost recovery. In this paper, we use the work of Pierre Bourdieu to synthesise these literatures, conceptualising communitas as ‘disaster social capital’. We offer a fleshed-out definition of disaster social capital to distinguish it from regular social capital and discuss the barriers to, and the enablers of, its formation. While primarily a conceptual discussion, we believe that it has practical and policy value for disaster scholars and practitioners interested in inclusive disaster risk reduction as well as full and just recoveries.     

A decade of monitoring at Swiss Long-Term Forest Ecosystem Research (LWF) sites: can we observe trends in atmospheric acid deposition and in soil solution acidity?

Trends in atmospheric acid deposition and in soil solution acidity from 1995 or later until 2007 were investigated at several forest sites throughout Switzerland to assess the effects of air pollution abatements on deposition and the response of the soil solution chemistry. Deposition of the major elements was estimated from throughfall and bulk deposition measurements at nine sites of the Swiss Long-Term Forest Ecosystem Research network (LWF) since 1995 or later. Soil solution was measured at seven plots at four soil depths since 1998 or later. Trends in the molar ratio of base cations to aluminum (BC/Al) in soil solutions and in concentrations and fluxes of inorganic N (NO(3)-N + NH(4)-N), sulfate (SO(4)-S), and base cations (BC) were used to detect changes in soil solution chemistry. Acid deposition significantly decreased at three out of the nine study sites due to a decrease in total N deposition. Total SO(4)-S deposition decreased at the nine sites, but due to the relatively low amount of SO(4)-S load compared to N deposition, it did not contribute to decrease acid deposition significantly. No trend in total BC deposition was detected. In the soil solution, no trend in concentrations and fluxes of BC, SO(4)-S, and inorganic N were found at most soil depths at five out of the seven sites. This suggests that the soil solution reacted very little to the changes in atmospheric deposition. A stronger reduction in base cations compared to aluminum was detected at two sites, which might indicate that acidification of the soil solution was proceeding faster at these sites.     

Comparison of Two Parametric Methods to Estimate Pesticide Mass Loads in California’s Central Valley1

Saleh, Dina K., David L. Lorenz, and Joseph L. Domagalski, 2010. Comparison of Two Parametric Methods to Estimate Pesticide Mass Loads in California’s Central Valley. Journal of the American Water Resources Association (JAWRA) 00(0):1‐11. DOI: 10.1111/j.1752‐1688.2010.00506.x Abstract: Mass loadings were calculated for four pesticides in two watersheds with different land uses in the Central Valley, California, by using two parametric models: (1) the Seasonal Wave model (SeaWave), in which a pulse signal is used to describe the annual cycle of pesticide occurrence in a stream, and (2) the Sine Wave model, in which first‐order Fourier series sine and cosine terms are used to simulate seasonal mass loading patterns. The models were applied to data collected during water years 1997 through 2005. The pesticides modeled were carbaryl, diazinon, metolachlor, and molinate. Results from the two models show that the ability to capture seasonal variations in pesticide concentrations was affected by pesticide use patterns and the methods by which pesticides are transported to streams. Estimated seasonal loads compared well with results from previous studies for both models. Loads estimated by the two models did not differ significantly from each other, with the exceptions of carbaryl and molinate during the precipitation season, where loads were affected by application patterns and rainfall. However, in watersheds with variable and intermittent pesticide applications, the SeaWave model is more suitable for use on the basis of its robust capability of describing seasonal variation of pesticide concentrations.     

The potential of spatial information in human biomonitoring by example of two German environmental epidemiology studies

This study aimed at statistically investigating the association between the internal exposure of children and young adults to uranium (U) and epidemiologically relevant external determinants of exposure. The investigation was performed with data from two studies within the framework of the German health-related environmental monitoring program: The German Environmental Survey for Children (GerES IV) conducted by the Federal Environment Agency (Umweltbundesamt) with data on 1,780 children 3–14 years of age and their home environment and the German Environmental Specimen Bank (ESB, section: human specimens) with data on 2,253 students 20–29 years of age. Both studies provided data on the U levels in human urine for all probands. GerES IV furthermore provided an extensive environmental and demographic database on, e.g., U levels in drinking water. The data from GerES IV and ESB were linked by GIS to spatially relevant exposure information, including background values of U in stream sediments and in upper and lower soils, U levels in mosses and particulate matter in the lower atmosphere, precipitation and elevation as well as forest density. Bivariate correlation analysis and two decision tree models showed moderate but significant associations between U in human urine and U levels in drinking water, stream sediments and upper and lower soils. Future investigations considering additional epidemiologically relevant data sets may differentiate the results. Furthermore, the sample design of future environmental epidemiology studies should take the spatial evaluation of the data into greater account.     

Determination of benzotriazoles in dishwasher tabs from Germany and estimation of the discharge into German waters

A method was developed for the determination of benzotriazoles (BTs) in dishwasher tabs. BTs consist of 1H-benzotriazole and/or tolyltriazole, i.e., a technical mixture of the two isomers 4-methylbenzotriazole and 5-methylbenzotriazole (5-MBT). The method consisted of weighing of an aliquot of the tab, addition of the internal standard 5-MBT, precipitation of the soaps with CaCl₂ and KOH, derivatization of the filtrate with acetic acid anhydride in a two-phase system, and analysis of the organic toluene layer by gas chromatography with mass spectrometry in the selected ion monitoring mode. Eleven of 12 different dishwasher tabs from the German market were tested positive with BTs ranging from 2 to 66 mg/tab. Dishwashing experiments were performed to show that at least 99 % of the BT amount used in the dishwasher did not remain on the dishes but was released into the wastewater treatment system. The annual release of BTs into the water system was estimated to be ~80 tons. Since 70 % or less of the BTs can be degraded in wastewater treatment plants, at least 24 tons are annually released into rivers in Germany.