The aim of the study was to specify the current status and direction of transformations of leaf beetle assemblages taking part in the rapid process of succession of vegetation towards the types of forest communities occurring in the Krzemionki Opatowskie reserve. At five sampling sites (in five plant associations) 30 species of Chrysomelidae were recorded. Five typical forest species (Chrysomela populi, Pyrrhalta viburni, Calomicrus pinicola, Altica brevicollis and Cryp-tocephalus labiatus) accounted for 16.67% of the number of species and 12.85% of the number of individuals caught in the reserve. The forest association richest in species (18) was Querco ro-boris-Pinetum (Que_Pin). This was followed by Tilio-Carpinetum association (Til_Car, 15 spp.), and then a mosaic of Tilio-Carpinetum and Querco roboris-Pinetum (Til_Car/Que_Pin), and Peucedano-Pinetum (Peu_Pin) (11 spp. each). The fewest number of species (10) were noted in Potentillo albae-Quercetum (Pot_Que). The most similar were the fauna of Potentillo albae--Quercetum (Pot_Que) and Querco roboris-Pinetum (Que_Pin) (55.08% similarity). The most distinct was the fauna of Peucedano-Pinetum (Peu_Pin). We can conclude that the structure of the leaf beetle assemblages in the forest associations studied in the reserve is at present an adaptive mixture of faunas characteristic of all the intermediate successional stages of vegetation, changing in this area in a relatively short time. The considerable diversity of fauna is the result of an ‘eco-tone in time’, i.e. the continuous presence of open-land species, which until recently had dominated here, accompanied by forest species characteristic of the current habitat types.

The aim of the study was to compare the physical-chemical quality parameters of shallow groundwater quality in peat bogs of the Łęczna-Włodawa Lake District in the context of the occurrence of selected boreal species of plant relics: dwarfbirch (Betula humilis Schrank), downy willow (Salix lapponum L. ) and swamp willow (Salix myrtylloides L. ). Analyzes of shallow groundwater quality parameters included physical-chemical parameters: reaction (pH), electrolytic conductivity(EC), dissolved organic carbon (DOC), total nitrogen (TN), ammonium nitrogen (NH4), nitrite nitrogen (NO2), nitrate nitrogen (NO3), total phosphorus (TP), phosphate (PO4), sulfate (SO2), sodium (Na), potassium (K), calcium (Ca) and mag-nesium (Mg) by certified laboratory tests.

It was found that the natural hydrochemical specification of peat bogs is characterized by fluctuations associated with the dynamics of internal metabolism of peat ecosystems without the visible impact of anthropopressure. This is confirmed by the concentration of nutrients: TNat the study sites were within a broad range of mean values: 16.92–45.31 mg·dm–3; NH4 (0.55–0.76 mg·dm–3); NO2 (0.06–4.33 mg·dm–3); and NO3 did not exceed 0.2 mg·dm–3, and concentration of TP adopted mean values in a range of 0.22–0.42 mg·dm–3.

The studied physical-chemical factors of shallow groundwater were within the habitat preferences of the studied species, but in differentiated qualitative and quantitative ways determined optimal conditions for building the population of the studied species. Particularly values of TP lower than other obtained values in a range of: 0.08–0.32 mg·dm–3; PO4 = 0.1 mg·dm–3; TN = 2.2–21.2 mg·dm–3; NH4 = 0.1–0.46 mg·dm–3; DOC = 24.6–55.9 mg·dm–3, as well as higher than average pH values in a range of: 5.34–5.95 and concentration of Ca = 5.67–28.1 mg·dm–3 and Mg = 0.56–2.41 mg·dm–3, as well as EC = 72.1–142.3 μS·cm–1 can be treated as a condition favouring proper development of the population of dwarf birch. For Salix lapponum: a reduced level of values of nitrogen fractions (TN = 3.01–18.84 mg·dm–3; NH4 = 0.1–0.41 mg·dm–3), a reduced level of values of phosphorus fractions (TP = 0.09–0.44 mg·dm–3; PO4 = 0.1–0.44 mg·dm–3), part of ions (Ca = 4.39–19.63 mg·dm–3; Mg = 0.77–3.37 mg·dm–3), pH = 5.9–6.4, EC = 124–266 μS·cm–1 and DOC = 24.1–57.5 mg·dm–3. For the equally studied Salix myrtylloides, such conditions were met by: TP = 0.1–0.41 mg·dm–3; PO4 = 0.1–0.18 mg·dm–3, DOC = 27.5–50.9 mg·dm–3, pH = 5.3–5.94 andEC = 62.2–139.3 μS·cm–1.

The study objective was to analyse the number of tourists present in the shore zone and bathing areas of lakes with regard to their tourist carrying capacity and the amount of biogenic substances potentially entering the ecosystem from the beach and bathing areas. The procedures from project between the EU and Poland, in the module “Development of the sanitary supervision of water quality” were used in three categories: physiological substances – sweat and urine; water-soluble and insoluble organic compounds; and biogenic elements – nitrogen and phosphorus. The research was conducted in two model mesotrophic lakes, Piaseczno and Zagłębocze, located in the Łęczna- Włodawa Lakeland (eastern Poland). The data were analysed in reference to biological trophic status indices defining the limnological status of lakes in the summer of 2014 and 2016. Analyses of gross primary production of phytoplankton using the light and dark bottles method and the analysis of chlorophyll a concentration were applied using the laboratory spectrophotometric method. The relatively small number of tourists recorded in the shore zone of both lakes did not exceed their tourist carrying capacity, and their potential contribution of biogenic substances to the lake ecosystems was small. Biological trophic indices for both lakes indicated that they had been continually late- mesotrophic for decades. The amount of biogenic substances directly linked to beach tourism usually has a minor effect on the limnological status of mesotrophic lakes. Due to the specific character of lake ecosystems, however, even small amounts of these substances can contribute to the destabilisation of the biocenotic system.