DIE ERDE – Journal of the Geographical Society of Berlin
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Anthropogenically altered runoff processes in a waterlogged headwater catchment within the National Park Hunsrück-Hochwald, Germany
Get PDFThis study is concerned with an initial investigation of anthropogenically altered runoff processes in a headwater catchment within the National Park Hunsrück-Hochwald (Germany) that is characterized by slope bogs and waterlogged soils. The examined area is crossed by a dense network of trenches, which were established in the course of forestry operations in order to utilize these waterlogged areas. An evaluation of the drainage network’s influence on runoff processes is attempted using water gauges and GIS-based analyses of the subcatchments. Results of the water year 2016 and a heavy rainfall event show that gauges in the study area react quickly to precipitation inputs and that water is retained only for a short time. The magnitude of runoff recession even in short dry spells permits the conclusion that the already merely residual slope bogs are endangered. The partial results of this study can serve as an instrument for rewetting actions as they allow spatially and temporally high resolved statements about the influence of drainage networks. Furthermore, this study is embedded in a long-term monitoring of hydrological processes and represents a first component of a detailed process-measurement taking place
Implications of hydraulic anisotropy in periglacial cover beds for flood simulation in low mountain ranges (Ore Mountains, Germany)
Get PDFThe simulation of floods with conceptual rainfall-runoff models is a frequently used method for various applications in flood risk management. In mountain areas, the identification of the optimum model parameters during the calibration is often difficult because of the complexity and variability of catchment properties and hydrological processes. Central European mountain ranges are typically covered by Pleistocene periglacial slope deposits. The hydraulic conductivity of the cover beds shows a high degree of anisotropy, so it is important to understand the role of this effect in flood models of mesoscale mountain watersheds. Based on previous field work, the study analyses the sensitivity of the NASIM modeling system to a variation of vertical and lateral hydraulic conductivity for the Upper Flöha watershed (Ore Mountains, Germany). Depending on the objective function (Nash-Sutcliffe coefficient, peak discharge), two diametric parameter sets were identified both resulting in a high goodness-of-fit for total discharge of the flood events, but only one reflects the hydrological process knowledge. In a second step, the knowledge of the spatial distribution of the cover beds is used to investigate the potential for a simplification of the model parameterisation. The soil types commonly used for the spatial discretisation of rainfall-runoff models were aggregated to one main class (periglacial cover beds only). With such a simplified model, the total flood discharge and the runoff components were simulated with the same goodness of fit as with the original model. In general, the results point out that the anisotropy in the unsaturated zone, which is intensified by periglacial cover beds, is an important element of flood models. First, a parameter set corresponding to the hydraulic anisotropy in the cover beds is essential for the optimum reproduction of the flood dynamics. Second, a discretisation of soil types is not necessarily required for flood modeling in Central European mountain areas
Plant species diversity of pastures in the Naryn Oblast (Kyrgyzstan)
Get PDFTraditional pastoral practices in Kyrgyzstan have been transformed into more intensive forms of pastoral land use during the Soviet colonial period, and once again modified after independence in 1991. Kyrgyz winter pastures close to settlements are subject to degradation processes, while remote summer pastures are less affected. It is largely unknown to what extent current grazing regimes, repeatedly modified during the post-Soviet transformation process, have influenced plant species diversity of mountain pastures. This paper aims to analyze inventory (α) and differentiation (β) diversity of pastures in the Naryn Oblast, where winter pastures are subject to increased grazing pressure. We used a non-asymptotic approach in order to infer Hill numbers, i.e. the effective number of species at different levels of q (where q = 0: species richness, q = 1: Shannon diversity, q = 2: Simpson diversity) to make fair comparisons among assemblages of winter and summer pastures. We established sample-size-based rarefaction (interpolation) and prediction (extrapolation) curves, and assessed beta diversity by implementing an ANOSIM and by calculating Jaccard and Sørensen indices. We also inspected the occurrence of rare endemic plants, which might play a key role in local ecosystem processes and are important for biodiversity conservation. Increased grazing pressure on winter pastures mainly results from abandoned seasonal livestock migration and unbalanced grazing intensity between seasonal pastures. Our results show that inventory diversity is higher on summer pastures and that species composition between summer and winter pastures differs significantly. Winter pastures are less species-rich but have a higher percentage of rare endemic species
An index for assessing activity friendliness for children in urban environments of Berlin
Get PDFThe physical environment strongly influences physical activity in urban settings. While walkability is frequently assessed for adults, an approach for mapping the friendliness of urban environments focusing on children’s activities is not available. The aim of the presented approach was to identify supporting and limiting factors of activity friendliness in urban environments and incorporate them into a children’s physical activity index (CAI). We conducted qualitative guided interviews with nine- to ten-year-old children and parents of primary school children in Berlin to identify the factors and their importance for describing activity friendliness. Access to activity and recreational destinations, land use, traffic and road safety, and the social environment were the most prominent factors identified for the activity friendliness for children. The newly developed CAI enables a differentiation in the activity friendliness of urban neighborhoods for children
Comparison of water consumption of three urban greening trees in a typical arid oasis citiy, northwest China
Get PDFIn order to ensure sustainable development of arid oasis cities, close attention must be paid to the rational use of limited water resources. Since urban vegetation is one important user of water, urban greening activities should be adapted to local environmental conditions. In this study, one native (Morus alba L.) and two introduced urban greening tree species (Fraxinus sogdiana Bunge and Platanus acerifolia Willd.) were selected in Aksu – a typical oasis city in northwest China. Their stem sap flow velocity (SFV) was determined and diel water consumption was calculated. In the meantime, meteorological variables were recorded to analyze the water consumption strategy of these tree species. The results show that the average SFV of M. alba, F. sogdiana and P. acerifolia were 4.1±0.3 cm h-1, 10.5±0.7 cm h-1 and 22.3±2.6 cm h-1, respectively. SFV was positively correlated with solar radiation (Rs), air temperature (Ta), vapor pressure deficit (VPD) and wind speed (Ws), and negatively correlated with air humidity (RH). Stepwise analysis showed that VPD had the highest impact on SFV of F. sogdiana (R²=0.987) and M. alba (R²=0.887), while the impact of RH was highest on P. acerifolia (R²=0.937). P. acerifolia had the highest sap flow daily accumulation (104±7 L tree-1), F. sogdiana was second (52±4 L tree-1), and third was M. alba (16±2 L tree-1). The water use efficiency (WUE) was M. alba (3.61 mmol mol-1) > F. sogdiana (3.33 mmol mol-1) > P. acerifolia (2.90 mmol mol-1). This study showed that native tree species developed certain adaptation strategies to the arid environment and thus consumed less water. Therefore, we recommend that in tree species selection by landscape planners as well as other decision makers, native tree species should be given priority in future urban greening projects
Surface runoff of horse grazed pasture – a disregarded hydrological response unit in low mountain ranges
Get PDFAccurate prediction of surface runoff is of vital interest for flood prediction which in turn requires the process knowledge about key factors affecting its temporal and spatial variability. Antecedent soil moisture and grazing intensity have been detected as important factors, but there exists no explicit field study investigating the spatial and temporal variability of surface runoff generation on horse grazed pasture. In our study, for the first time the surface runoff generation on horse grazed pasture was analyzed using a rainfall simulator along with measurements of soil water content and soil physical properties. The results were compared with concurrent investigations on cattle grazed pasture land. The analyses of 8 rainfall simulations on 1 m² plots at a rate of 46.6 mm/h revealed mean runoff coefficients ranging from 0.9% to 50.5%. The most important findings of our study are that the antecedent soil moisture distinctly impacts the amount of surface runoff and the runoff coefficient is significantly higher on horse grazed pasture than on cattle grazed pasture. These results underline the importance of further experimental studies to obtain a broader process knowledge about this specific hydrological response unit, especially in regard to the increasing portion of horse grazing in the low mountain ranges
Heavy metal contamination of soils in China: standards, geographic distribution, and food safety considerations. A review
Get PDFThis article reviews the conditions of heavy metal contamination of China’s soils. The article starts with a discussion of the official environmental standards of soils in China, in terms of heavy metal contamination, and the extent of that contamination. Then, the article discusses the geographic distribution of soil contamination, and the food safety impact. The problem in China is that the provinces with the highest rates of soil contamination are also provinces with the largest amount of food production. This results in high contamination of food, with 13.86 % of grain produced in China being affected by heavy metal contamination. Hunan Province represents the worst conditions: it is responsible for 32.1 % of China’s cadmium (Cd) emissions, 20.6 % of its arsenic (As) emissions, 58.7 % of its mercury (Hg) emissions, and 24.6 % of its lead (Pb) emissions. While Hunan Province produces about 15 % of the total rice output of the country, according to official data, 13 % ofthe total area of the province has been contaminated with waste and heavy metals from mines. In many areas, especially those closer to mines, the agricultural production exceeds the official food safety standards
Change of regulating ecosystem services in the Danube floodplain over the past 150 years induced by land use change and human infrastructure
Get PDFEcosystem services in floodplains are manifold. The regulating services regarding hydrological issues (e.g. flood protection, water purification) are of particular importance along rivers, and depend strongly on size and land use of the floodplain. In this paper, we transfer the commonly known land use changes in floodplains over the last 150 years into significant changes of the amount of different regulating ecosystem services. We investigated a floodplain stretch of 17 km along the Danube in Germany (approx. 90 km²). Thus, we mapped the spatial expansion of the active floodplain and the land use distribution for three different times: the earliest (not the pristine) state of 1869 on the basis of a historical map, 1963 after river regulation and 2013 as navigation channel with a hydropower dam on the basis of aerial photographs. The land use types woodland, grassland, arable land, settlements, and water bodies were distinguished. On the basis of land use as a proxy, we calculated the potential of four ecosystem services (flood retention, nitrogen and phosphorous retention, habitat provision) according to the method of Scholz et al. (2012a). The spatial extension of the active floodplain was continuously reduced from 56 km² (1869) to 18 km² (1963) to 11 km² (2013). The amount of grassland and arable land was reduced significantly in the active floodplain, whereas woodland increased. This entails a decrease of f lood retention (-80%), and nutrient retention (nitrogen: -60%, phosphor: -76%). Likewise, habitat provision was significantly reduced. In total, the potential benefits for humans have been negatively affected over the time by land use change and, above all, by the construction of embankments. Therefore, ecosystem services should be regarded by future floodplain management
Challenges for transboundary river management in Eastern Europe – three case studies
Get PDFThe transboundary river basins shared between Russia, Ukraine and the European Union pose unique challenges for management because of differences regarding not only the legal framework but also related to monitoring practices and water utilization. Using the example of three river basins – the Desna (shared by Russia and Ukraine), the Western Dvina (shared by Russia, Belarus, Lithuania, Estonia and Latvia) and the Western Bug (shared by Ukraine, Belarus and Poland) – this paper provides an analysis of current challenges with respect to transboundary water resources management in Eastern Europe. This assessment is based on a comparison of similarities and disparities concerning the physical and human geography of the basins (and their national sub-basins) as well as specific problems related to water pollution caused by urban, agricultural and industrial water usage both in the recent past and today. All three catchments have a similar size, climate and hydrological characteristics. However, there are different challenges regarding up- and downstream sections of the respective basins: pollution input in the Western Bug originates primarily from upstream sources in Ukraine and Belarus, whereas ecological problems in the Desna and Western Dvina persist principally downstream, i.e. in Ukraine respectively Belarus and Latvia. Despite some differences between the basins, it is concluded that interstate cooperation is an important prerequisite for integrated water resources management (IWRM) in all of the studied basins. This analysis identified several key challenges related to start or continue with IWRM, including pollution mitigation, improved monitoring, appropriate governance, climate change and its effect on water balances in the catchments, capacity development and thorough system understanding