The role of surface runoff from forested areas in chemical cycling and freshwater ecology is still not completely understood. Changes in total precipitation and increase in heavy rainfalls may, however, in some regions promote the effect of runoff in aquatic environments. In this study, we aimed to investigate the physicochemical properties of the surface runoff occurring within the wooded catchment area of a through-flow lake (Poland, Europe). Samples were collected over a 2-year period from slopes overgrown by the monoculture of Scots pine (Pinus sylvestris) or mixed forest dominated by European beech (Fagus sylvatica) and Scots pine. At the same time, the chemical properties of littoral and pelagic zones were analysed. Waters overflowing both slopes were found to have low pH, high colour and relatively high content of dissolved organic carbon and nutrients. Compared to coniferous site, the runoff from mixed forest was represented by significantly higher concentrations of organic matter, nitrogen, phosphorus and calcium ions. The greatest changes of the studied chemical parameters were noted in runoff occurring during heavy rainfall and snow melting (coniferous slope) or after shedding of leaves (the mixed forest slope). Surface runoff was revealed to be less important source of chemical loads in basins with direct river inflow but for more isolated basins it may be a significant factor affecting water quality.

The paper presents the results of an examination of the phycical-chemical parameters of water together with an analysis of the chlorophyll a concentration of 12 small water bodies situated within urban and suburban areas of the city of Poznań (mid-west Poland)-typical midforest, strongly anthropogenically modified in the urban landscape, strongly antropogenically modified in an agricultural area and clay-pits. There were zones of open water (Unvegetated Zone) as well as zones of rush and aquatic vegetation (Vegetated Zone) distinguished in the examined ponds. The influence of the rush vegetation, nymphaeids and elodeids on the abiotic parameters of an aquatic environment was examined. Water samples were taken during the summer of 2004 from 12 stations within the open water and 24 within macrophytes. The plant matter was randomly collected in triplicate from the central part of the vegetated stand. The influence of macrophytes on the abiotic features of water was estimated using the parameter of the plant length (cm l -1 ) and the plant biomass (g l -1 ). In the studied ponds 12 aquatic macrophyte communities were distinguished. A salient feature of submerged macrophytes was a great density of plant stems along with considerebly low biomass, however, the rush vegetation (Phragmitetum communis, Typhetum latifoliae) when compared to nymphaeids (Polygonetum natantis, Potametum natantis) and elodeids (Potametum lucentis) was characterised by lower stem densities and higher biomass. The water bodies were alkaline and of pronounced hardness. In most of them high trophy conditions were found with especially high concentrations of phosphorus (96 lg l -1 on average). There was significant differentiation in the water chemistry (mainly in respect to mineral compounds) between the Vegetated and Unvegetated Zones as well as between particular aquatic macrophyte communities.

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In order to determine whether using indicators of zooplankton diversity and macrophyte parameters (density and biomass) could be a useful tool for diagnosing the water quality of ponds we hypothesised that in various trophic types of shallow water bodies parameters of a macrophyte habitat will reflect zooplankton diversity. Thus, 439 stations (open water, helophytes, elodeids) were studied among 274 pastoral ponds (mid-west Poland). In each trophic state of waters a key predictor of zooplankton diversity was biomass of macrophytes attributed to a variety of ecological types or various species of macrophytes. A shift from the high importance of elodeids (e.g. Myriophyllum, Ceratophyllum demersum) in structuring zooplankton diversity in mesotrophic waters to helophytes (Typha angustifolia, Phragmites australis, Schoenoplectus lacustris) in hypereutrophic ponds was recorded. Hypereutrophy proved to be extremely unfavourable for zooplankton, as reflected in its lowest diversity; rotifers reached their optimum in eutrophy and crustaceans in mesotrophy. Adverse environmental conditions in hypereutrophic waters caused the elimination of macrophyte-dominated refuges, thereby lowering the macrophyte-site share, which ranged from 47% in eutrophy, 40% in mesotrophy to only 20% in hypereutrophy. Therefore, we assume that zooplankton diversity and macrophyte occurrence can be used for quality assessment of small water bodies.

Understanding the influence of environmental factors on the hydrobiota structure of small aquatic ecosystems is essential for effective landscape management. In this study of 165 small water bodies situated in the lowland high-productive agricultural landscape of western Poland we evaluate the effect of catchment, buffer zone, water body and water quality parameters on macrophyte functional groups (nymphaeids, elodeids, pleustophytes, helophytes) and zooplankton diversity. The potential pressure of the catchment on ponds was high (mean Ohle index 140). For macrophytes, shore length and depth of pond were highly significant and, subsequently the type of catchment and buffer, while for zooplankton, apart from water depth, trophic features of the habitat were decisive. Cluster analysis was used to identify functional types of water bodies on the basis of catchment and buffer zone attributes. Regardless of physicogeographical macroregion, water bodies of arable catchments with herbage buffer prevailed in a landscape. For protection and prevention of ecological deterioration of ponds and stability of trophic conditions the optimal situation is a buffer which is created by shrubs and trees around the pond.

The aim of the study was to evaluate the trophic conditions of the waters of twelve small ponds based on the analysis of their physical and chemical parameters according to Carlson's Trophic State Index and OECD. Great differentiation in the trophic status of ponds located in different varieties of landscape was observed and ranged from mesotrophic to weak eutrophic conditions in mid-forest ponds and clay-pits, eutrophic conditions in pastoral ponds, and hypertrophic conditions in urban water bodies. Throughout the analysis, a number of limitations in the classification methods of trophic conditions in the examined water bodies were noted. The specific problems were the shallow depth of ponds, which often corresponded with the depth of the Secchi disc transparency, or the complete overgrowing of the pond water column by macrophytes.

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