During the research of the flora of the river Moravica methodology of ass. Scirpo-Phragmitetum, Koch 1926, subass. typhetosum latifoliae, Pignotti 1953, with differential typa Typha latifolia with related marshy plants was applied. The community is developed as small units in the lower flow of the river Moravica (the part flowing through the town Aleksinac), where the anthropogenic influences are significant due to the empting of the sewage and industrial polluted waters of the town Aleksinac. Many diffuse forms of pollution are also present, particularly in the form of illegal dumps. Waste waters represent serious load on the recipient river and influence qualitative and quantitative content of the phytocenosis. Ecological index of the community shows change in water quality and presence of organic substances (above all nitrogen compounds) in the water and the riverbed ass. Scirpo-Phragmitetum, Koch 1926, subass. typhetosum latifoliae, Pignotti 1953, which indicates the riverbed loaded with organic substances (mezotrophic plants, N=3.50)

Composition of benthic macroinvertebrates and phytoplankton were examined during the period of July-November 2006, for purposes of freshwater quality assessment in protected area of Jegricka water body. Results of research show intensive sedimentation of organic matter in river bed, which is caused by eutrophication processes and small flow velocity in this canalized river of Vojvodina.

Scarce natural resources which are important for development of society or civilization itself are the issue of research for economists from the point of view of their efficient utilization. Theory of natural monopoly asserts that for society is better to treat scarce resources as monopoly than to put them on free market. The assertion is that it is better to invest in development of other markets than into free competition in sphere of some scarce resources. Main aim of this paper is to overview some elements of theory of natural monopoly.

Global expansion and intensification of industrialized agriculture during the last 50 years was facilitated by the replacement of labor by imported chemicals and energy, thus changing the economics and the social fabric of rural communities as well as impairing water, air, and soil resources essential to sustaining food and fiber production in a world with an increasing appetite. To effectively understand and solve complex problems resulting from this agricultural revolution, expanded communications are needed at a variety of levels. It is critical for the technical community to communicate through greater interdisciplinary research among agronomists, soil scientists, hydrologists, ecologists, and others to reduce diffuse pollution from agriculture. Also, more effective translations of technical problems and solutions are needed to influence policy. Accurate advice is needed in spite of the uncertainties that scientists too often use to obscure useful information. Education will be needed for producers and conservationists to gain confidence that promised environmental responses will occur if solutions are to be implemented at more than experimental or demonstration scales. The search for comprehensive solutions to environmental degradation will require understanding the ultimate causes of pollution, not just the proximal causes. The ultimate causes will only be found by examining the systems that facilitate the release of contaminants to the environment such as the wholesale landscape changes that replaced grazing land with annual crops leading to increased leaching and runoff. Research and demonstration projects increasingly need collaborations among agronomists, livestock scientists, soil scientists, hydrologists, economists, sociologists and others who have a stake in the study of diffuse pollution and the outcomes of any proposed solutions. Partnerships developed at the working level where basic principles can be shared will help avoid the pursuit of impractical solutions when viewed from different perspectives.