## 4 Results  
A total of 235 species of vascular plants (233 species in 2015 and 225 species in 2018) from 56 families, representing four botanic classes, were indentified in plant communities of shores of Lake Piaseczno in 2015 and 2018. In class MAGNOLIOPSIDA, the highest species richness concerned families Asteraceae (25 species); Rosaceae (17 species); Plantaginaceae (11 species); Lamiaceae (11 species); and Cariophyllaceae and Salicaceae (10 species each). In class LILIOPSIDA, the highest species richness concerned Peaceae (26 species) and Cyperaceae (19 species). The remaining families in all classes were represented much less abundantly (compare Table 3). The tree, shrub and small tree vegetation included 35 species from 10 families belonging to two botanical classes. The most abundant representation concerned families Salicaceae (10 species) and Rosaceae (8 species), and the least abundant representation concerned families Adoxaceae, Oleaceae, Sapindaceae and Pinaceae (1 species each). For both study years, the sector with the highest number of species was the recreational-agricultural sector (RA, 138 species in 2015 and 135 species in 2018). In 2015, the lowest number of species was identified in the recreational sector (R, 115 species), and in 2018 in the forest-recreational sector (FR, 109 species), where an almost 7% decrease in the number of species was recorded in comparison to the previous study year (Table 3). The occurrence of 29 species permanently present in all sectors for both study seasons was determined: _Achillea millefolium, Bidens tripartita, Eupatorium cannabinum, Hieracium pilosella, Hieracium murorum, Tussilago farfara, Myostis palustris, Stellaria graminea, Calluna vulgaris, Lotus conriculatus, Mentha arensis, Prunella vulgaris, Rumex acetosa, Rumex acetosella, Ranunculus flanmuula, Potentilla erecta, Galium plaustre, Urtica dioica, Alisma plantago-aquatica, Carex flava, Juncus conglomeratus, Agrostis capillaries and Holcus lanatus, and among tree and shrub vegetation: _Quercus robur_, _Populus tremula_, _Salix aurita_, _Salix cinerea_, _Salix pentandra_ and _Pinus sylvestris_. A total of 59 species of plants occurring in only one study sector was also identified. The highest number of such species occurred in the peathog-forest-recreational sector (PFR, 27 species) and forest-recreational sector (FR, 24 species). The remaining study sectors showed less varied character: recreational-agricultural sector (RA, four species); recreational sector (R, zero species). Part of a species occurring in only one sector was found in only one study year, namely 2015 (FR: _Aegopodium podagaria_, _Mycelis muralis_, _Knauttia arensis_, _Scirpus sylvaticus_, _Bromus hordaecus_, _Festuca altissima_; PFR: _Vicia angustifolia_, _Polygonum lapathifolium_, _Rumex crispus_, _Carex riparian_, _Carex rostrata_; RA: _Chelidonium majus_); and in 2018, only _Capsella bursa-pastoris_ in FR and _Cerastium holostenoides_ in RA (Table 3). In terms of life forms according to [PERSON], for both study years, plant communities of shore sectors of Lake Piaseczno were dominated by hemicryptophytes (H), reaching almost a 60% contribution. Geophytes (G) and terophytes (T) showed more than a 14% share in phytocoenoses. Hydrohyptes and helophytes (Hy) reached 11%, megaphanerophytes (M) and nanophanerophytes (N) 7-8%, and green chamaephytes (C) and woody chamaephytes (Ch) showed a maximum of several percent participation in the shore communities of Piaseczno. Low representation also concerned lianas (li, two species) and semi-parasites (pp, one species) (Table 4). In the phytosociological context, sector PFR was dominated by plant species from the classes Molinio-Arhenathereeta, Oxycocco-Sphagnetea, Phragmiteeta and Scheuzierio-Caricetea nigrae; sectors R and RA were dominated by plant species from the classes Phragmiteeta and Molinio-Arhenathereeta; and sector FR was dominated by plant species from the classes Phragmiteeta, Querco roboris-Pinetum and Nardo-Callunetea.