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Soil organic matter (SOM) is an essential soil constituent. The deficiency of SOM is an essential problem in many regions in Poland. Diversity of organic matter and the environment create varying structures and compositions, and thus differences in properties of humic substances (HS) especially humic acids (HAs). It was found that soil amendment with organic matter resulted in improving of soil and HAs properties compared with non-treatment ones. The results obtained provided the following evidences. With respect to HAs: an increasing content of carboxylic groups in HAs from amended soils; a major content of aromatic ring systems; higher carbon, nitrogen, hydrogen, and sulphur and lower oxygen contents comparing to the control; the addition of straw caused an increase of carbon content in HAs particles and, consequently a decrease of the C:H ratio; higher content of oxygen functional groups compared with non-treated ones. Organic matter from straw is more resistant to fast decomposition as compared to compost and it shows higher long-term sorption capacity. Therefore, straw may be an equivalent to natural sources of SOM in terms of agriculture and ecosystems protection.
Water dependent ecosystems are habitats most vulnerable to urbanization pressure. There are not many such habitats in Warsaw. Those which remained are mostly dewatered sites existing within green areas such as parks. Habitats with peat and moorsh soils have a unique value, thus there is a rational need for detailed research and evaluation to preserve them. This paper is a case-study of two different water dependent ecosystems, localized within the boundaries of Poland’s capital city, both remaining under strong urbanization pressure. Different actions were undertaken to preserve those habitats, with differing results. We examined tendencies of vegetation during recent 20–30 years, basing on fl oristical data. In the areas, where water regime has been disrupted, like Natural Landscape Complex “Olszyna” a significant decline of plants rare in the scale of Warsaw is being noticed. Habitats not disturbed by human interference like ”Zakole Wawerskie” do not suffer significant changes, even an increase of rare plants was marked. Presence of water dependent ecosystems is also correlated with population density. In the areas of highest population density these habitats occur seldom, are of a small size and have simplified border zones. The only areas within Warsaw borders where water dependent ecosystems maintained are the urban parks. In the last decades a progressive decline of wetlands is being noticed, which was also confirmed in this study. The only real chance for further preservation of this areas is to create biodiversity hotspots and good recreation infrastructure.
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Chemical criteria in the critical loads concept

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The critical loads concept has been developed under the Convention on Long-Range Transboundary Air Pollution as a scientific basis for the negotiations of its environmentally effect-oriented protocols. The basic idea of this concept is to balance the atmospheric depositions which a given ecosystem is exposed to with the capacity of this ecosystem to buffer the input in the system. Accordingly, a critical loads approach to control acidic emissions in relation to their ecological effects has been introduced. Critical load is defined as "a quantitative estimate of an exposure to one or more pollutants below which significant harmful effects on specified sensitive elements of the environment do not occur according to present knowledge". In this study, the critical loads approach has been applied to the problem of forest ecosystem acidification resulting from sulfur and nitrogen emission. There are several criteria that may be used as critical chemical limits in forest soil solution. These are critical pH, critical Al concentration, critical BC/A1 ratio and Al depletion criterion. The reliability of the calculated critical loads is strongly influenced by the quality of the chemical criteria applied. For abiotic aspects like soil chemistry or ground water quality the critical limits are clear because the dose-effect relations are quite well understood. For biotic indicators like root damage it is more difficult to find critical limits which can be used as threshold levels below which effects are negligible. The process of root damage is quite a complex one and a combination of side factors like droughts and adverse soil chemical condition may contribute to it. So, when a single critical limit such as the ВС/Al ratio is used, this will inherently lead to a considerable uncertainty in the value of this critical limit. Critical limits are based on laboratory experiments during a limited period of time in which sample roots are subject to constantly elevated BC/A1 ratios. One of major problems in applying this kind of criteria is the interpretation of the laboratory bioassay results in relation to field conditions. The aim of this paper is to summarize the current knowledge and to formulate the major questions that should be answered to abate the existing uncertainty in relating the anthropogenically modified soil chemistry and the reaction of forest ecosystems.
The paper presents a review of research on functioning of agricultural landscape, mainly on protection of ecosystem services, carried out by the Institute for Agricultural and Forest Environment, Polish Academy of Sciences in Turew in the period of 1970-2009. The paper concentrates on water balance and water pollution control and the protection of biodiversity in an agricultural landscape. The results of the researches show that the best way for maintenance ecosystem services is development of landscape complexity. Introduction of non-productive elements like shelterbelts, strips of meadows, small ponds allows for improvement of water balance, reduction of groundwater pollution even by 90% and enhancement of biodiversity.
The Baltic Sea covers an area of 415 000 km2. A typical brackish sea, it is very sensitive to anthropogenic activities. Inorganic nutrients, trace metals, chlorinated hydrocarbons and crude oil products are contaminants studied in the Baltic Monitoring Programme of HELCOM. The data collected by the riparian countries forms the basis for the periodic assessments of the state of the marine environment of the Baltic Sea Area produced by HELCOM every five years. Since 1992 marine nature conservation has been part of the HELCOM convention. According to the third status report issued in 1996, it was the first time that HELCOM could strike a positive balance with regard to the decreasing environmental load. This is also reflected in lower concentrations of harmful substances in fish, marine mammals and seabirds in the Baltic Sea Area. The reasons for this progress are the protective actions initiated by HELCOM and the economic collapse in some of the former East Bloc countries, the latter resulting in an abrupt fall in industrial and agricultural production. Although the restoration of the Baltic ecosystem has only just begun, the protective measures introduced to achieve this aim can serve as an example of how to solve similar problems in other semi-enclosed basins and shelf seas.
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