Vigilance behaviour and fitness consequences: comparing a solitary foraging and an obligate group-foraging mammal

Vigilance behaviour in gregarious species has been studied extensively, especially the relationship between individual vigilance and group size, which is often negative. Relatively little is known about the effect of conspecifics on vigilance in non-obligate social species or the influence of sociality itself on antipredator tactics. We investigated predator avoidance behaviour in the yellow mongoose, Cynictis penicillata, a group-living solitary forager, and compared it with a sympatric group-living, group-foraging herpestid, the meerkat, Suricata suricatta. In yellow mongooses, the presence of conspecifics during foraging—an infrequent occurrence—reduced their foraging time and success and increased individual vigilance, contrary to the classical group-size effect. Comparing the two herpestids, sociality did not appear to affect overt vigilance or survival rates but influenced general patterns of predator avoidance. Whereas meerkats relied on communal vigilance, costly vigilance postures, and auditory warnings against danger, yellow mongooses avoided predator detection by remaining close to safe refuges and increasing “low-cost” vigilance, which did not interfere with foraging. We suggest that foraging group size in herpestids is constrained by species-distinct vigilance patterns, in addition to habitat and prey preference.     

Analysis of brominated flame retardants in house dust

The main objective of this study was to create a robust analytical method to analyse the flame retardants decabromodiphenylether (BDE-209), hexabromocyclododecane (HBCD), and tetrabromobisphenol-A (TBBPA) in house dust in order to estimate the degree of contamination of indoor environment. A liquid chromatography method equipped with a UV-detector and electro spray-tandem mass spectrometry was used to achieve this result. Applying an external calibration for BDE-209, an internal calibration for TBBPA, and a standard addition method for HBCD low limits of quantification were obtained. The analytical procedure was carried out under exclusion of UV-light as the target compounds potentially degrade when being exposed to UV-light. Empirical data were obtained in addition to the dust samples to estimate potential influences of apartment characteristics. A weak correlation between the number of electric devices and TBBPA was found.     

Molecular effects and bioaccumulation of levonorgestrel in the non-target organism Dreissena polymorpha

Bioaccumulation and effects of the contraceptive hormone levonorgestrel were examined in the non-target organism Dreissena polymorpha. Molecular biomarkers of biotransformation, elimination, antioxidant defence and protein damage were analyzed after exposure to increasing concentrations of levonorgestrel in a flow-through system. The lowest concentration (0.312 μg L⁻¹) was 100-fold bioconcentrated within four days. A decrease of the bioconcentration factor was observed within one week for the highest test concentrations (3.12 and 6.24 μg L⁻¹) suggesting enhanced excretory processes. The immediate mRNA up-regulation of pi class glutathione S-transferase proved that phase II biotransformation processes were induced. Disturbance of fundamental cell functions was assumed since the aryl hydrocarbon receptor has been permanently down-regulated. mRNA up-regulation of P-glycoprotein, superoxide dismutase and metallothioneine suggested enhanced elimination processes and ongoing oxidative stress. mRNA up-regulation of heat shock protein 70 in mussels exposed to the two highest concentrations clearly indicated impacts on protein damage.     

Sustainable management of transboundary river basins: a line of reasoning

This paper identifies a line of reasoning based on a number of concepts and tools to facilitate river basin management, which have been applied in a case study. For long-term sustainable river basin management, a balance is needed between the human use of the river and its basin, the ecological functioning of the river and receiving waters, and the river's capacity to supply goods and services. To find such a balance a framework is needed that illustrates and clarifies possible trade-offs between economic use and environmental supply by integrating scientific information on cause–effect chains on a catchment scale. A number of concepts and tools are proposed as a basis for this framework. The tools are: (1) indicators that describe the complex interactions and processes in rivers; (2) a suite of linked models that predict the economic, environmental and ecological effect of management measures; (3) an evaluation framework to rank different management alternatives on the basis of three objectives: economic efficiency, spatial equity in costs and benefits and environmental quality of the river and receiving lakes. The concept of environmental quality defines the potential of the river environment (i.e. natural capital) to contribute to human welfare. The concept of environmental functions is used to identify societal interest in natural capital. The concept and tools have been applied in a case study involving the evaluation of four management strategies on nutrient abatement in the Rhine basin. The result of the case study is that economic efficiency is in conflict with spatial equity and environmental quality. Spatial equity is in agreement with environmental quality. Electronic Publication     

RED RIVER OF THE NORTH BASIN,MINNESOTA, NORTH DAKOTA,AND SOUTH DAKOTA1

ABSTRACT: The environmental setting of the Red River of the North basin within the United States is diverse in ways that could significantly control the areal distribution and flow of water and, therefore, the distribution and concentration of constituents that affect water quality. Continental glaciers shaped a landscape of very flat lake plains near the center of the basin, and gently rolling uplands, lakes, and wetlands along the basin margins. The fertile, black, fine-grained soils and landscape are conducive to agriculture. Productive cropland covers 66 percent of the land area. The principal crops are wheat, barley, soybeans, sunflowers, corn, and hay. Pasture, forests, open water, and wetlands comprise most of the remaining land area. About one-third of the 1990 population (511,000) lives in the cities of Fargo and Grand Forks, North Dakota and Moorhead, Minnesota. The climate of the Red River of the North basin is continental and ranges from dry subhumid in the western part of the basin to subhumid in the eastern part. From its origin, the Red River of the North meanders northward for 394 miles to the Canadian border, a path that is nearly double the straight-line distance. The Red River of the North normally receives over 75 percent of its annual flow from the eastern tributaries as a result of regional patterns of precipitation, evapotranspiration, soils, and topography. Most runoff occurs in spring and early summer as a result of rains falling on melting snow or heavy rains falling on saturated soils. Lakes, prairie potholes, and wetlands are abundant in most physiographic areas outside of the Red River Valley Lake Plain. Dams, drainage ditches, and wetlands alter the residence time of water, thereby affecting the amount of sediment, biota, and dissolved constituents carried by the water. Ground water available to wells, streams, and springs primarily comes from sand and gravel aquifers near land surface or buried within 100 to 300 feet of glacial drift that mantles the entire Red River of the North basin. Water moves through the system of bedrock and glacial-drift aquifers in a regional flow system generally toward the Red River of the North and in complex local flow systems controlled by local topography. Many of the bedrock and glacial-drift aquifers are hydraulically connected to streams in the region. The total water use in 1990, about 196 million gallons per day, was mostly for public supply and irrigation. Slightly more than one half of the water used comes from ground-water sources compared to surface-water sources. Most municipalities obtain their water from ground-water sources. However, the largest cities (Fargo, Grand Forks and Moorhead) obtain most of their water from the Red River of the North. The types and relative amounts of various habitats change among the five primary ecological regions within the Red River of the North basin. Headwater tributaries are more diverse and tend to be similar to middle-reach tributaries in character rather than the lower reaches of these tributaries for the Red River of the North. Concentrations of dissolved chemical constituents in surface waters are normally low during spring runoff and after thunderstorms. The Red River of the North generally has a dissolved-solids concentration less than 600 milligrams per liter with mean values ranging from 347 milligrams per liter near the headwaters to 406 milligrams per liter at the Canadian border near Emerson, Manitoba. Calcium and magnesium are the principal cations and bicarbonate is the principal anion along most of the reach of the Red River of the North. Dissolved-solids concentrations generally are lower in the eastern tributaries than in the tributaries draining the western part of the basin. At times of low flow, when water in streams is largely from ground-water seepage, the water quality more reflects the chemistry of the glacial-drift aquifer system. Ground water in the surficial aquifers commonly is a calcium bicarbonate type with dissolved-solids concentration generally between 300 and 700 milligrams per liter. As the ground water moves down gradient, dissolved-solids concentration increases, and magnesium and sulfate are predominant ions. Water in sedimentary bedrock aquifers is predominantly sodium and chloride and is characterized by dissolved-solids concentrations in excess of 1,000 milligrams per liter. Sediment erosion by wind and water can be increased by cultivation practices and by livestock that trample streambanks. Nitrate-nitrogen concentrations also can increase locally in surficial aquifers beneath cropland that is fertilized, particularly where irrigated. Nitrogen and phosphorous in surface runoff from cropland fertilizers and nitrogen from manure can contribute nutrients to lakes, reservoirs, and streams. Some of the more persistent pesticides, such as atrazine, have been detected in the Red River of the North. Few data are available to conclusively define the presence or absence of pesticides and their break-down products in Red River of the North basin aquifers or streams. Urban runoff and treated effluent from municipalities are discharged into streams. These point discharges contain some quantity of organic compounds from storm runoff, turf-applied pesticides, and trace metals. The largest releases of treated-municipal wastes are from the population centers along the Red River of the North and its larger tributaries. Sugar-beet refining, potato processing, poultry and meat packing, and milk, cheese, and cream processing are among the major food processes from which treated wastes are released to streams, mostly in or near the Red River of the North.     

Biogeochemical C and N cycles in urban soils

The percentage of urban population is projected to increase drastically. In 2030, 50.7 to 86.7% of the total population in Africa and Northern America may live in urban areas, respectively. The effects of the attendant increases in urban land uses on biogeochemical C and N cycles are, however, largely unknown. Biogeochemical cycles in urban ecosystems are altered directly and indirectly by human activities. Direct effects include changes in the biological, chemical and physical soil properties and processes in urban soils. Indirect effects of urban environments on biogeochemical cycles may be attributed to the introductions of exotic plant and animal species and atmospheric deposition of pollutants. Urbanization may also affect the regional and global atmospheric climate by the urban heat island and pollution island effect. On the other hand, urban soils have the potential to store large amounts of soil organic carbon (SOC) and, thus, contribute to mitigating increases in atmospheric CO(2) concentrations. However, the amount of SOC stored in urban soils is highly variable in space and time, and depends among others on soil parent material and land use. The SOC pool in 0.3-m depth may range between 16 and 232 Mg ha(-1), and between 15 and 285 Mg ha(-1) in 1-m depth. Thus, depending on the soil replaced or disturbed, urban soils may have higher or lower SOC pools, but very little is known. This review provides an overview of the biogeochemical cycling of C and N in urban soils, with a focus on the effects of urban land use and management on soil organic matter (SOM). In view of the increase in atmospheric CO(2) and reactive N concentrations as a result of urbanization, urban land use planning must also include strategies to sequester C in soil, and also enhance the N sink in urban soils and vegetation. This will strengthen soil ecological functions such as retention of nutrients, hazardous compounds and water, and also improve urban ecosystem services by promoting soil fertility.     

Phthalates in house dust

The main objective of this study was to generate a fast analytical method to determine the five phthalates benzylbutylphthalate (BBP), dibutylphthalate (DBP), di-(2-ethylhexyl)-phthalate (DEHP), di-isodecylphthalate (DIDP), and di-isononylphthalate (DINP) in house dust. To achieve this liquid chromatography electrospray tandem mass spectrometry (LC–ESI–MS/MS) was used for measurement. The risk of lab- and cross-contamination was nearly eliminated completely as a very short and fast sample preparation including a sieving step and an ultrasonic extraction for the analytes from the dust samples was used. Quantification through internal standard calibration resulted in low limits of determination (DEHP 4 mg kg^? 1 to DBP 14 mg kg^? 1). A potential interaction between the analytes DIDP and DINP during chromatographic measurement could be excluded while performing a two level factorial design. Furthermore it was examined to what extend carpet and plastic materials respectively have influence on the total amount of phthalates in dust. It could be shown that apartments in which a minimum of both of these sources appeared revealed the lowest total amount of sum of phthalates in dust (median 362 mg kg^? 1).