This paper reports the preliminary results from the studies on the scanning electron microscopical studies on chrysophycean cysts collected in ponds and streams of King George Island (South Shetlands). The cysts play an important role as the survival developmental stages. Fifteen morphotypes are described, six of which are new for science. Particular attention has been paid to the anatomy of the pore, collar structure and to the ornamentation of the cyst surface.
One of the most interesting and relatively little-known water acosystems of ”Lasy Janowskie” Natural Landscape Park is its old ponds which have been in most cases excluded from intensive fisheries for many decades. Four of them were studied in 1996, 2005 and 2013, regarding their planktonic rotifer assemblages. The total of 60 rotifer taxa were observed in the plankton. The number of their species in individual reservoirs ranged from 7 to 21, while their density amounted to 33–775 ind. dm-3. As many as 21 of the species observed in individual water bodies and study periods belonged to dominants. While watching the changes occurring in the plankton during the period of 17 years , we were trying to determine which of those tiny reservoirs were inhabited by more sustainable rorifer assemblages and which ecological qualities were more closely related to such sustainability: species richness, its diversity, density, bio-mass, composition or domination structure. The results of the studies revealed slight variability of ecological properties in planktonic rotifer assemblages in the ponds composing large reservoir groups, and significantly higher variability of those qualities in ”single” ponds, not belonging to large complexes.
The aim of study was to evaluate the richness and distribution of the aquatic macrophytes in ponds. . Studies were carried out in July 2013 and July 2014 on the six largest and oldest ponds (functioning since the First World War) in the Łęczna-Włodawa Lake District – Sosnowica ponds. Studies have shown that despite the fishing use of ponds, they can provide valuable habitat for aquatic plants biodiversity. Distribution of plants in the ponds was typical mosaic. Phytolittoral often developed from one bank to another. Macrophyte beds occupied a significantly large percentage of the studied pond areas. Emergent macrophytes were dominant group of macrophytes in investigated ponds.
The species diversity, density and similarity of Gastrotrich fauna of bottom sediments to epiphytic fauna in three farm ponds were investigated. In the studied habitats 31 species of Gas-trotricha belonging to the family of Chaetonotidae were found altogether. In bottom sediments of the ponds there were 29 and on plants 17 species of Gastrotricha. Three species (Heterolepido-derma gracile Rmane, 1927, Chaetonotus disjunctus Greuter, 1917 and Ch. oculifer Kisielewski, 1981) were found to be dominants in bottom sediments with the dominance over 10.0%. H. gracile and Ch. oculifer also occur on vegetation, but their dominance is significantly lower. In turn three species (H. macrops Kisielewski, 1981, H. ocellatum (Mečnikow, 1865) and Lepidodermella squamata (Dujardin, 1841) proved to be dominant on water vegetation, with the dominance over 10.0% in all studied ponds. The value of species diversity index H’ including the number of spe-cies and uniformity of their dominance is from 2.76 to 2.93 for bottom sediments and from 2.60 to 2.72 for plants. The total density of gastrotrich fauna in bottom sediments fluctuated from 350.0 to 920.0 103 indiv. m-2 and on elodeids from 520 to 1110 103 indiv. m-2. The density of gastrotrich fauna of elodeids was higher than in bottom sediments in all the studied ponds. In each of the ponds examined, the differences are statistically significant. The similarity between bottom sediment fauna and epiphytic fauna in each of the studied ponds, cal-culated according to the homogeneity index, was very low and ranged from 44% to 48%.
In two fish ponds in Lasy Janowskie Landscape Park 48 water mite species were caught. In the pond Momoty Duże, situated in the Lasy Janowskie reserve, more species (38), higher species diversity (3.88), and a larger share of lake fauna (33.2%) were observed than in Momoty Małe (33, 3.67 and 22.6% respectively). In the combined collected material small water body species were dominant (70.6%). Similarity between the Hydrachnidia assemblages of the two ponds was 50.1%. The large number of species and individuals caught and the high values for the species diversity index confirm the significant role of fish ponds as a habitat for water mites. A characteristic trait of the ponds was the very small percentage of vernal species and of tyrphobiontic and tyrphophilic species. Although more species and a larger share of lake fauna were found in the pond situated in the reserve (Momoty Duże) than in the pond outside the reserve (Momoty Małe), the differences in the structure of the fauna were slight. The lack of pronounced differences between the two ponds was due to their similar habitat characteristics and similar use.
Water reservoirs are very valuable floristic sites in Poland. Among them, the most im-portant for preservation of biodiversity of flora are fishponds. The long-term process of human pressure on habitats of this type caused disturbance of their biological balance. Changes in the water regime, industrial development and chemisation of agriculture, especially in the period of last two centuries, led to systematic disappearance of localities of many plant species and plant communities. Gnaphalio uliginosi-Eleocharitetum acicularis Passarge 1999, of Isoëto-Nanojuncetea class Br.-Bl. et Tx. 1943, was firstly described in Germany. This association grows on sandy or sandy-gravely banks of rivers and in old river beds. In Poland, Gnaphalio uliginosi-Eleocharitetum acicularis has not been found so far. The patches of this type have been described many times, but otherwise classified acording to syntakxonomical system. During current vegetation research the association Gnaphalio uliginosi-Eleocharitetum acicularis was found in seven fish-breeding ponds in south-western Poland. Fieldworks were conducted in 2000–2016.