scholarly journals Factors influencing the number of breeding water birds in Lake Engure, Latvia

2011 ◽  
Vol 65 (5-6) ◽  
pp. 127-137
Author(s):  
Jānis Vīksne ◽  
Māra Janaus ◽  
Aivars Mednis
Keyword(s):  
Water Level ◽  
Natura 2000 ◽  
Vegetation Succession ◽  
Natural Food ◽  
Lake Area ◽  
Nature Protection ◽  
Factors Influencing ◽  
Water Birds ◽  
Indirect Impacts ◽  
The Impact

Factors influencing the number of breeding water birds in Lake Engure, Latvia Lake Engure has attracted great interest since the middle of the 19th century when the water level of the lake was lowered by construction of a canal. The lake area decreased from 90 km2to about 45 km2, and favourable conditions were created for development of emergent vegetation (presently covers 58.6% of area). A nature protection regime was established in 1957. The lake was included in the Important Bird Area list in 1994, in the Ramsar lists in 1995, and as part of the Natura 2000 network in 2004. The present paper deals mostly with data collected by the Laboratory of Ornithology, Institute of Biology, in the period 1948-2011. Direct and indirect impacts of climate, human activities, water level, vegetation succession, anthropogenic and natural food and predation on water birds (coot, waders, ducks, larids and grebes), as well as relationships between these water bird groups, were demonstrated. The impact of vegetation succession via overgrowing of meadows with reed and bushes, merging of the mosaic of small stands of emergents into huge reed dominated massives (thus reducing areas of habitats suitable for water birds) is described. The relation of Black-headed Gull population size with availability/unavailability of anthropogenic food and the associated changes in breeding duck numbers, as well as predation structure are discussed.

scholarly journals Water quality of springs alongside Srebarna lake: preliminary chemical analysis / Jakość wody źródlanej wzdłuż jeziora Srebarna: wstępna analiza chemiczna

2012 ◽  
Vol 19 (4) ◽  
pp. 639-647
Author(s):  
Elka Kraleva ◽  
Milena Pavlova ◽  
Elisa Mazo Bedia ◽  
Petya Borisova ◽  
Luchezar Pehlivanov
Keyword(s):  
Drinking Water ◽  
Ecological Status ◽  
Biosphere Reserve ◽  
Natura 2000 ◽  
Intensive Agriculture ◽  
Natural State ◽  
Lake Ecosystem ◽  
Lake Area ◽  
Natura 2000 Site ◽  
The Impact

Abstract The Srebarna Lake Biosphere Reserve is a protected natural site of national and international significance. It characterizes with extremely high biodiversity, being one of the last wetlands along the Lower Danube preserved in relatively natural state; the lake area is NATURA 2000 site. This study was designed to further research on the impact of intensive agriculture on the lake’s ecological status. First task was to find an evidence for link between intensive agriculture and the loading of the lake with nutrients. The second was a study on the PAH’s penetration into the lake ecosystem. An overview was made on drinking water data for 2 underground (drinking water springs). Dyakova spring’s water displayed good ecological state after measured parameters PO3-4 , NO2-3, NO- 2 and pH. Todorankina spring did not fell within the boundaries of good and very good conditions. Increased nitrate levels in water samples leads us to conclude that agriculture in this part of the surrounding area affect groundwater quality in the biosphere reserve. Results from GC-MS analysis proved, that there is no groundwater contamination, responsible for the existing (although low) concentrations of PAH found in the lake.

scholarly journals Using Multisource Satellite Data to Investigate Lake Area, Water Level, and Water Storage Changes of Terminal Lakes in Ungauged Regions

2021 ◽  
Vol 13 (16) ◽  
pp. 3221
Author(s):  
Chuanhui Zhang ◽  
Aifeng Lv ◽  
Wenbin Zhu ◽  
Guobiao Yao ◽  
Shanshan Qi
Keyword(s):  
Water Level ◽  
Satellite Data ◽  
Water Resource Management ◽  
Water Storage ◽  
Integral Model ◽  
Lake Area ◽  
Terminal Lakes ◽  
The Impact ◽  
Area Data

Lake area, water level, and water storage changes of terminal lakes are vital for regional water resource management and for understanding local hydrological processes. Nevertheless, due to the complex geographical conditions, it is difficult to investigate and analyze this change in ungauged regions. This study focuses on the ungauged, semi-arid Gahai Lake, a typical small terminal lake in the Qaidam Basin. In addition to the scant observed data, satellite altimetry is scarce for the excessively large fraction of outlier points. Here, we proposed an effective and simple algorithm for extracting available lake elevation points from CryoSat-2, ICESat-2 and Sentinel-3. Combining with the area data from Landsat, Gaofen (GF), and Ziyuan (ZY) satellites, we built an optimal hypsographic curve (lake area versus water level) based on the existing short-term data. Cross-validation was used to validate whether the curve accurately could predict the lake water level in other periods. In addition, we used multisource high-resolution images including Landsat and digital maps to extract the area data from 1975 to 2020, and we applied the curve to estimate the water level for the corresponding period. Additionally, we adopted the pyramidal frustum model (PFM) and the integral model (IM) to estimate the long-term water storage changes, and analyzed the differences between these two models. We found that there has been an obvious change in the area, water level, and water storage since the beginning of the 21st century, which reflects the impact of climate change and human activities on hydrologic processes in the basin. Importantly, agricultural activities have caused a rapid increase in water storage in the Gahai Lake over the past decade. We collected as much multisource satellite data as possible; thus, we estimated the long-term variations in the area, water level, and water storage of a small terminal lake combining multiple models, which can provide an effective method to monitor lake changes in ungauged basins.

How to Psychologically Minimize Scratching Impulses

2014 ◽  
Vol 222 (3) ◽  
pp. 140-147 ◽  
Author(s):  
Ariane Sölle ◽  
Theresa Bartholomäus ◽  
Margitta Worm ◽  
Regine Klinger
Keyword(s):  
Cognitive Processes ◽  
Placebo Effect ◽  
Psychological Factors ◽  
Pharmacological Treatments ◽  
Physiological Basis ◽  
Psychological Mechanisms ◽  
Physical Complaints ◽  
Factors Influencing ◽  
The Impact ◽  
Placebo Model

Research in recent years, especially in the analgesic field, has intensively studied the placebo effect and its mechanisms. It has been shown that physical complaints can be efficiently reduced via learning and cognitive processes (conditioning and expectancies). However, despite evidence demonstrating a large variety of physiological similarities between pain and itch, the possible transfer of the analgesic placebo model to itch has not yet been widely discussed in research. This review therefore aims at highlighting potential transfers of placebo mechanisms to itch processes by demonstrating the therapeutic issues in pharmacological treatments for pruritus on a physiological basis and by discussing the impact of psychological mechanisms and psychological factors influencing itch sensations.

Study on Prediction Model of Karstic Large Spring Water Level Dynamic Coupling Multiple Factors in Jinan

2015 ◽  
Vol 8 (1) ◽  
pp. 309-317 ◽  
Author(s):  
Xing Liting ◽  
Zhou Juan ◽  
Zhang Fengjuan ◽  
Wang Song ◽  
Dou Tongwen ◽  
...  
Keyword(s):  
Prediction Model ◽  
Water Level ◽  
Spring Water ◽  
Anthropogenic Factors ◽  
Karst Water ◽  
Multiple Factors ◽  
Factors Influencing ◽  
Heterogeneous Features ◽  
Dry Seasons ◽  
Natural Decay

In karst regions, due to the heterogeneous features of karst medium, the characteristics of the groundwater flow turn to be of high complexity. Researchers have been seeking proper forecasting methods for karst water dynamic for many years. This paper, taking the spring in Jinan as an example, using regression analysis, analyzed the factors influencing spring water dynamic, and quantitatively evaluated the influencing coefficients of spring water level concerning rainfall, exploitation and recharge as well as the natural decay coefficient of spring water in dry seasons. The prediction model coupling multiple factors was built by investigating natural and anthropogenic factors influencing groundwater level, which could be used for forecasting dynamic of spring water in Jinan. The calculated value of model was highly coincided with the observed value. In consideration of the characteristics of uneven precipitation in Jinan, the suitable zones and volume of artificial recharge were investigated finally, which could help to sustain the spewing of Jinan springs significantly.

scholarly journals Impact of Entrepreneurship Extracurricular Activities and Inspiration on Entrepreneurial Intention: Mediator and Moderator Effect

SAGE Open ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 215824402110321
Author(s):  
Thuy Thu Nguyen ◽  
Linh Thi Phuong Nguyen ◽  
Hoa Thi Thanh Phan ◽  
Anh Trong Vu
Keyword(s):  
Extracurricular Activities ◽  
Structural Equation ◽  
Entrepreneurial Intention ◽  
Equation Modeling ◽  
Moderator Effect ◽  
Technical Students ◽  
Research Findings ◽  
Direct And Indirect Impacts ◽  
Indirect Impacts ◽  
The Impact

This empirical study proposed a comprehensive model testing the direct and indirect impacts of entrepreneurship extracurricular activities and entrepreneurship inspiration on students’ entrepreneurial intention. With the sample consisting of 640 students from 11 universities in Vietnam, the study used structural equation modeling analysis approach. The results revealed that entrepreneurship extracurricular activities and entrepreneurship inspiration are significantly related to students’ entrepreneurial intention, and entrepreneurship self-efficacy partially mediates these relations. The impact of entrepreneurship education on entrepreneurial intention differs across the field of study. Technical students generally get more benefits from entrepreneurship educational activities than business and economics students do. The research findings recommended some implications for fostering graduates’ entrepreneurship in emerging countries.

scholarly journals Assessing Stream-Aquifer Connectivity in a Coastal California Watershed

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 416
Author(s):  
Bwalya Malama ◽  
Devin Pritchard-Peterson ◽  
John J. Jasbinsek ◽  
Christopher Surfleet
Keyword(s):  
Time Series ◽  
Spectral Analysis ◽  
Water Level ◽  
Time Series Data ◽  
Series Data ◽  
Low Permeability ◽  
Pumping Tests ◽  
Stream Flows ◽  
The Impact

We report the results of field and laboratory investigations of stream-aquifer interactions in a watershed along the California coast to assess the impact of groundwater pumping for irrigation on stream flows. The methods used include subsurface sediment sampling using direct-push drilling, laboratory permeability and particle size analyses of sediment, piezometer installation and instrumentation, stream discharge and stage monitoring, pumping tests for aquifer characterization, resistivity surveys, and long-term passive monitoring of stream stage and groundwater levels. Spectral analysis of long-term water level data was used to assess correlation between stream and groundwater level time series data. The investigations revealed the presence of a thin low permeability silt-clay aquitard unit between the main aquifer and the stream. This suggested a three layer conceptual model of the subsurface comprising unconfined and confined aquifers separated by an aquitard layer. This was broadly confirmed by resistivity surveys and pumping tests, the latter of which indicated the occurrence of leakage across the aquitard. The aquitard was determined to be 2–3 orders of magnitude less permeable than the aquifer, which is indicative of weak stream-aquifer connectivity and was confirmed by spectral analysis of stream-aquifer water level time series. The results illustrate the importance of site-specific investigations and suggest that even in systems where the stream is not in direct hydraulic contact with the producing aquifer, long-term stream depletion can occur due to leakage across low permeability units. This has implications for management of stream flows, groundwater abstraction, and water resources management during prolonged periods of drought.

Lake and inland dunes as interconnected Systems: The story of Lake Tresssee and an adjacent dune field (Schleswig-Holstein, North Germany)

The Holocene ◽  
2020 ◽  
pp. 095968362098168
Author(s):  
Christian Stolz ◽  
Magdalena Suchora ◽  
Irena A Pidek ◽  
Alexander Fülling
Keyword(s):  
Water Level ◽  
Bronze Age ◽  
Environmental Changes ◽  
High Water ◽  
Alluvial Fan ◽  
Water Levels ◽  
Lake Area ◽  
Dune Field ◽  
The North ◽  
Sand Drift

The specific aim of the study was to investigate how four adjacent geomorphological systems – a lake, a dune field, a small alluvial fan and a slope system – responded to the same impacts. Lake Tresssee is a shallow lake in the North of Germany (Schleswig-Holstein). During the Holocene, the lake’s water surface declined drastically, predominately as a consequence of human impact. The adjacent inland dune field shows several traces of former sand drift events. Using 30 new radiocarbon ages and the results of 16 OSL samples, this study aims to create a new timeline tracing the interaction between lake and dunes, as well, as how both the lake and the dunes reacted to environmental changes. The water level of the lake is presumed to have peaked during the period before the Younger Dryas (YD; start at 10.73 ka BC). After the Boreal period (OSL age 8050 ± 690 BC) the level must have undergone fluctuations triggered by climatic events and the first human influences. The last demonstrable high water level was during the Late Bronze Age (1003–844 cal. BC). The first to the 9th century AD saw slightly shrinking water levels, and more significant ones thereafter. In the 19th century, the lake area was artificially reduced to a minimum by the human population. In the dunes, a total of seven different phases of sand drift were demonstrated for the last 13,000 years. It is one of the most precisely dated inland-dune chronologies of Central Europe. The small alluvial fan took shape mainly between the 13th and 17th centuries AD. After 1700 cal. BC (Middle Bronze Age), and again during the sixth and seventh centuries AD, we find enhanced slope activity with the formation of Holocene colluvia.

scholarly journals Modelling natural regeneration of European beech in Saxony, Germany: identifying factors influencing the occurrence and density of regeneration

2021 ◽  
Author(s):  
Maximilian Axer ◽  
Sven Martens ◽  
Robert Schlicht ◽  
Sven Wagner
Keyword(s):  
Natural Regeneration ◽  
Negative Binomial ◽  
European Beech ◽  
Seed Source ◽  
Permanent Plots ◽  
Forest Conversion ◽  
Ecological Knowledge ◽  
Statistical Tool ◽  
Factors Influencing ◽  
The Impact

AbstractThe potential utilisation of natural regeneration of European beech (Fagus sylvatica L.) for forest conversion has received little attention to date. Ecological knowledge is necessary to understand and predict successful natural regeneration of beech. The objective of this study was to improve understanding of what drives the occurrence of beech regeneration and, once regeneration is present, what drives its density. In the study, we utilised a forest inventory dataset provided by Sachsenforst, the state forestry service of Saxony, Germany. The dataset was derived from 8725 permanent plots. Zero-altered negative binomial models (ZANB) with spatial random effects were used to analyse factors influencing occurrence and density simultaneously. The results provided by the spatial ZANB models revealed that the probability of the occurrence of beech regeneration is highly dependent on seed availability, i.e. dependent on source trees in close proximity to a plot. The probability of beech regeneration rises with the increasing diameter of a potential seed tree and decreases with increasing distance to the nearest potential seed source. The occurrence of regeneration is affected by overstorey composition and competition exerted by spruce regeneration. Where sites are affected by groundwater or temporary waterlogging, the impact on the occurrence of regeneration is negative. Although distance to the nearest potential seed source has an influence on occurrence, this variable exerts no influence on density. A high regeneration density arises in conjunction with a high beech basal area in the overstorey. Beech regeneration density, but not occurrence, is negatively affected by browsing intensity. These variables can be used to predict the occurrence and density of beech regeneration in space to a high level of precision. The established statistical tool can be used for decision-making when planning forest conversion using natural regeneration.

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