Landscapes and environments on the island of Ouessant,Brittany, France: From traditional maintenance to the management of abandoned areas

For about 50 years the desertion of areas by traditional activities has led to an important evolution of landscapes and environments on the island of Ouessant. The study of this evolution has been undertaken at different spatial and temporal scales. On one part of the island, a scientific investigation carried out at the scale of the parcel enabled the form of the landscape in 1850 to be compared with that of 1985. On the whole island, the evolution of spatial organization and land use was compared between 1950 and 1985. For each of three main ecological environments, vegetational successions after the decrease of agriculture have been studied along with their future potential changes. This work highlights some considerations about the present management of the environment in relation to the major objectives of island environmental policies.     

Interpretation of analytical data on n-alkanes and polynuclear aromatic hydrocarbons in Arbacia lixula from the coasts of Tenerife (Canary Islands, Spain) by multivariate data analysis

The hydrocarbons contents (n-alkanes, polycyclic aromatic hydrocarbons) were determined in the sea urchin Arbacia lixula. Multivariate data analysis as principal component analysis, factor analysis and, cluster analysis were applied to elucidate sources of pollution. PCA and FA were performed to establish the relationships between variables (hydrocarbons), samples (sea urchin) and sources of pollution.     

Feeding habits of marine cladocerans in the Inland Sea of Japan

Natural food items of five species of marine cladocerans, Evadne nordmanni, E. tergestina, Penilia avirostris, Podon leuckarti and P. polyphemoides, were investigated in the Inland Sea of Japan between April 1986 and May 1987. Gut content examination with SEM (scanning electron microscopy) revealed that feeding was largely limited to centric diatoms and a few exceptions of pennate diatoms and dinoflagellates. No animal remains were detected, and some unidentified materials were also found. Phytoplankton smaller than 35 m in size (cell diameter in centric diatoms and longest dimension in others) was found most frequently in the gut of cladocerans. The role of grazing of marine cladocerans in trophodynamic pathways of the pelagic realm is discussed.     

Trace Element Patterns and Seasonal Variability of Dust Precipitation in a Low Polluted City – The Example of Karlsruhe/Germany

Urban areas of different land uses can be distinguished by their specific patterns of atmospheric dust and trace element precipitation. Dusts emitted from industrial areas with fossil fuel processing, for instance, are enriched in V, Ni and Co. Cluster analysis groups sampling sites based on their specific element patterns. The resulting groups correspond to the surrounding land use: Urban sampling sites were identified showing similar patterns of dust and trace element precipitation as a reference site; dusts of other urban sites were influenced by diffuse pollution (caused by non-point and dispersed pollution sources), or by specific industrial emissions. Cluster analysis was also used to characterize the chemical dust composition. Three clusters of typical element associations were distinguished. These clusters represent the dust matrix, diffuse urban pollution and pollution due to fossil fuel processing. Dust precipitation and chemical dust composition show seasonal variations. Dust precipitation and concentrations of trace elements in the precipitated dust are negatively correlated during the annual courses. The highest concentrations of trace elements occur during winter, whereas the highest precipitations of dust were found during summer. This finding stresses that both, precipitation and concentration have to be addressed for the environmental assessment of urban dusts.     

Chromium (III) recovery from waste acid solution by ion exchange processing using Amberlite IR-120 resin: batch and continuous ion exchange modelling

The use of ion exchange technology was studied to remove chromium (III) from acidic waste solution by Amberlite IR-120 resin. Batch and column experimental tests were conducted to provide data for theoretical models and verify the system performance of the adsorption process. Results of batch equilibrium tests indicated that Langmuir isotherm describes well the adsorption process, whereas experimental data also provide evidence that, under the present experimental conditions, chromium (III) adsorption by Amberlite IR-120 resin is film-diffusion controlled; on the other hand, the theoretical model used in the present investigation was found to predict reasonably well the ion exchange breakthrough performance.     

The ecological relevance of current approaches for environmental protection from exposure to ionising radiation

This paper discusses the current approaches to environmental protection from ionising radiation from an ecological perspective, highlighting the need to understand fully what we are trying to protect. Ecologically relevant endpoints for environmental protection are discussed along with the need to integrate protection from ionising radiation with the approaches adopted for non-radioactive contaminants. A possible integrated assessment approach is outlined.     

Toward Adaptive Management: The Impacts of Different Management Strategies on Fish Stocks and Fisheries in a Large Regulated Lake

We applied the adaptive management approach to analyze the demand and feasibility of adaptive management of fish stocks in a large regulated lake, Oulujärvi, in northern Finland. The process consisted of four phases: (1) analysis of the current state of the fisheries system (fishers, related markets and industry, fisheries researches and authorities, related organizations, etc.); (2) analysis of the objectives of different stakeholders; (3) the composition of alternative management strategies and assessment of their impacts; and (4) recommendations for future management. We used catch statistics from the period 1973–1995 to analyze fish stocks and fishing. Fish species involved were brown trout (Salmo trutta L.), whitefish [Coregonus lavaretus (L.) sl.], vendace (Coregonus albula L.); and pikeperch (Stizostedion lucioperca L.). Questionnaires and interviews were applied to ascertain the opinions of different groups of fishermen. Several models and cost–benefit analysis were used to assess the ecological, economic, and social impacts of three alternative management strategies. The results emphasize that when determining stocking levels and fishing regulations, the system should be considered as a whole, and impacts on major fish species and different groups of fishermen should be assessed. The stocking policy and fishing regulations should also be flexible to accommodate changing biotic and societal conditions. The key questions in applying the adaptive management process in Oulujärvi fisheries are how to determine clear objectives for fisheries management, find a fisheries management structure that provides workable interactions between different stakeholders, and arrange cost-effective monitoring. The lessons learned from the Oulujärvi experience and recommendations for fisheries management are relevant to other lakes with conflicting objectives of different stakeholders.     

Modeling flow and nitrate fate at catchment scale in Brittany (France)

In the intensive pig-farming (Sus scrofa) area of Brittany (western France), many surface and subsurface water resources are contaminated by nitrate (NO3) with concentrations that chronically exceed the European Community 50 mg L(-1) drinking standard. To ensure sustainable water supply, the fate of NO3 must be considered in both surface water and ground water. The fate of N was investigated in a Britain catchment, the Co?t-Dan watershed, with an integrated management tool: the hydrological SWAT model coupled with the ground water model MODFLOW, and its companion contaminant and solute transport model MT3DMS. The model was validated with respect to water quantity during a 6-yr period and for the NO3 concentration during a 44-mo period, at two gauging stations in the catchment. The coupled models reproduced accurately the measurements. At the basin outlet, the Nash-Sutcliffe coefficients were 0.88 for monthly flow for the entire period and 0.87 for monthly N load. Alternative scenarios were simulated and showed potential benefits of decreasing manure application from 210 to 170 kg N ha(-1) as required by the European Commission Nitrates Directive.     

Agricultural Land Use Effects on Sediment Loading and Fish Assemblages in Two Minnesota (USA) Watersheds

We examined the relationship between water quality and fish communities within two agricultural areas using a computer simulation model. Our analyses focused on a coolwater stream, Wells Creek in southeastern Minnesota, and a warmwater stream, the Chippewa River in western Minnesota. We used the Agricultural Drainage and Pesticide Transport (ADAPT) model in relation to land use to calculate instream suspended sediment concentrations using estimates of sediment delivery, runoff, baseflow and streambank erosion, and quantified the effects of suspended sediment exposure on fish communities. We predicted the effects of agricultural practices on stream fish communities under several possible land use scenarios, with reference to current conditions. Land use changes led to reductions in sediment loading of up to 84% in Wells Creek and 49% in the Chippewa River. The reduction in sediment loading across scenarios may be directly related to a reduction in runoff by about 35% in both study areas. We found a 98% decrease in lethal concentrations of suspended sediment on fish in Wells Creek with an increase in conservation tillage, riparian buffers, and permanent vegetative cover. However, the effects of suspended sediment did not significantly decrease in the Chippewa River. This difference between study areas was likely due to differences in tolerance to suspended sediment between coolwater and warmwater fish communities and differences in topography, runoff and bank erosion between the two streams. The Minnesota Cooperative Fish and Wildlife Research Unit is jointly sponsored by the US Geological Survey, the University of Minnesota, the Minnesota Department of Natural Resources, and the Wildlife Management Institute.