The diets of common and Brünnich's guillemots Uria aalge and U. lomvia in the Barents Sea region

Guillemots Uria spp. account for ca. 70% of the total harvest of prey taken by seabirds breeding in the Barents Sea region. This paper presents guillemot chick diet data collected recently at four localities (Finnmark, Murman, Bjørnøya and Spitsbergen) and collates all the data found by the authors in the literature and in the archives of Tromsø Museum, the Norwegian Polar Institute and Kandalaksha State Nature Reserve. Guillemots consume a wide variety of prey and, in comparison to the harvest by predatory fish and marine mammals, their impact on the Barents Sea ecosystem is considered to be minimal. We point out the need for more systematic collection of data from different regions and at different times of the year before a final impact assessment can be made.     

The water-ecological problems of territorial development

The resolution of the issues related to the prevention of ecological problems having a technogenic as well as a natural character relies on a knowledge of the formation patterns of hydrological processes, which makes it possible to rationally manage water resources, ecologically transform landscapes, and minimize the consequences of socio-economic development of the territory. The theoretical foundations of landscape-hydrological analysis, combined with the principles of instrumental landscape planning, determine the system of basin management, and some methods for tackling the water-ecological problems.     

Neural network modelling of planform geometry of headland-bay beaches

The shoreline of beaches in the lee of coastal salients or man-made structures, usually known as headland-bay beaches, has a distinctive curvature; wave fronts curve as a result of wave diffraction at the headland and in turn cause the shoreline to bend. The ensuing curved planform is of great interest both as a peculiar landform and in the context of engineering projects in which it is necessary to predict how a coastal structure will affect the sandy shoreline in its lee. A number of empirical models have been put forward, each based on a specific equation. A novel approach, based on the application of artificial neural networks, is presented in this work. Unlike the conventional method, no particular equation of the planform is embedded in the model. Instead, it is the model itself that learns about the problem from a series of examples of headland-bay beaches (the training set) and thereafter applies this self-acquired knowledge to other cases (the test set) for validation. Twenty-three headland-bay beaches from around the world were selected, of which sixteen and seven make up the training and test sets, respectively. As there is no well-developed theory for deciding upon the most convenient neural network architecture to deal with a particular data set, an experimental study was conducted in which ten different architectures with one and two hidden neuron layers and five training algorithms – 50 different options combining network architecture and training algorithm – were compared. Each of these options was implemented, trained and tested in order to find the best-performing approach for modelling the planform of headland-bay beaches. Finally, the selected neural network model was compared with a state-of-the-art planform model and was shown to outperform it.     

Epiphytic diatoms as flood indicators

The hydroecology of floodplain lakes is strongly regulated by flood events. The threat of climate warming and increasing human activities requires development of scientific methods to quantify changes in the frequency of short-lived flood events, because they remain difficult to identify using conventional paleolimnological and monitoring approaches. We developed an approach to detect floods in sediment records by comparing the abundance and composition of epiphytic diatom communities in flooded and non-flooded ponds of the Peace-Athabasca Delta (PAD), Canada, that grew on submerged macrophytes (Potamogeton zosteriformis, P. perfoliatus) and an artificial substrate (polypropylene sheets) during the open-water season of 2005. Analysis of similarity tests showed that epiphytic diatom community composition differs significantly between flooded and non-flooded ponds. After accounting for the “pond effect,” paired comparisons of the three substrates determined that variation in community composition between the artificial substrate and macrophytes was similar to that between the macrophyte taxa. Similarity percentage analysis identified diatom taxa that discriminate between flooded and non-flooded ponds. The relative abundance of ‘strong flood indicator taxa’ was used to construct an event-scale flood record spanning the past 180 years using analyses of sedimentary diatom assemblages from a closed-drainage pond (PAD 5). Results were verified by close agreement with an independent paleoflood record from a nearby flood-prone oxbow pond (PAD 54) and historical records. Comparison of epiphytic diatoms in flooded and non-flooded lakes in this study provides a promising approach to detect changes in flood frequency, and may have applications for reconstructing other pulse-type disturbances such as hurricanes and pollutant spills.     

Past environmental change and seawater intrusion into coastal Lake Lilaste,Latvia

Diatoms, organic matter and magnetic susceptibility in a 10-m-long sediment sequence from coastal Lake Lilaste, Latvia, were analysed to evaluate Holocene environmental changes related to past sea-water intrusions. Lake Lilaste is located ~1 km from the present sea coast in an area with a low uplift rate and a threshold altitude of 0.5 m a.s.l. It was thus considered to be an appropriate site to study the influence of past sea level fluctuations on the lake and its sediments. Variations in diatom community composition, along with sediment lithostratigraphy, show that a shallow, nutrient-rich freshwater lake existed there during the early Holocene. The first brackish-water diatoms appeared concurrent with a sea level rise ca. 8700 ± 50 cal a BP, but long-term, intermittent inputs of brackish water were observed between 6700 ± 40 and 4200 ± 80 cal a BP. During those time spans, diatoms indicate increased nutrient concentrations and high conductivity, a consequence of occasional mixing of brackish and freshwater that promoted biological productivity. Lilaste was isolated from the sea at 4200 ± 80 cal a BP, after which a stable freshwater environment, dominated by planktonic diatoms such as Aulacoseira ambigua, A. granulata, A. islandica and A. subarctica, was established. At 400 ± 50 cal a BP, planktonic diatoms were gradually replaced by Fragilaria spp., indicating the beginning of anthropogenic impact. The reconstructed relative water-level curve from the lake coincides with the eustatic sea level curve from 6800 ± 40 cal a BP onwards. There was a distinct increase in abundance of brackish-water diatoms when the sea level reached the threshold of Lilaste, which at that time was probably about 3 m lower than the present sea level. According to radiocarbon-dated shifts in the diatom community composition, the Litorina Sea transgression was a long-lasting event (ca. 2200 years) in the southern part of the Gulf of Riga, where the land uplift rate was near zero. It culminated more than 1000 years later than at other sites with higher uplift, in the northern part of the Baltic Sea.     

Accommodation of ecological and economic interests in placer gold mining

An attempt is made to find the answer to the question as to why the measures of the environmental institutions of Russia are ineffective for the avoidance and prevention of the degradation of aquatic ecosystems in placer gold mining. It is established that the size of payments to be made by companies engaged in placer gold mining are such that they almost cannot stimulate any nature conservation initiatives. Moreover, they even cannot be the argument for observance of environmental legislation. It is shown that the high transaction costs borne by the State, with minor expenditures of nature resource users connected with the protection of environmental natural systems fail to achieve the objectives imposed upon the supervising institutions. It is established that local authorities are directly interested in increasing placer gold mining as well as in gaining the loyalty of artels implying registration of the enterprise in this region, because these tax proceeds are exceptionally important for municipal formations facing a chronic financial deficit, a budgetary uncertainty and a dependence on regional and federal subsidies and transfers. Finance flows were calculated and analyzed to show that a very important problem for Russia’s eastern regions that involves reconciling the economic and ecological interests in placer gold mining is not resolved through “cosmetic changes” in organs of state supervision. It is concluded that there is a need for new institutional solutions in order to create and increase incentives for users of mineral resources and local authorities for observance of environmental regulations, the preservation and restoration of disturbed ecosystems, and for the ecologization of production processes.     

Forecasting metropolitan and urban subregional population changes and their resource use implications: methodology and example--Sydney,Australia

This paper is concerned with the methodology of forecasting population change and structures of large cities and their major subregions. "The model isolates quantifiable base populations and their growth, and international, inter-state and city-hinterland migration streams and the national increase attributable to each, and intra-urban mobility, as components of growth and change." The model is applied to data for Sydney, Australia, and its applicability to other urban systems is considered.