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EN
From 1979 to 1981 investigations of breeding birds communities were conducted in four oak-hornbeam reserves situated in Pilica Forest. In the „Błogie” and „Gaik” reserves the abundance of breeding birds was determined by using mapping technique in two subsequent breeding seasons. A total of 66 breeding bird species within the area of this reserves was recorded. The highest number 61 species was found in the „Błogie” reserve and lower number 48, 44 and 31 in the „Jeleń”, „Gaik” and „Spała” reserves respectively. The density of pairs ranged from 92 to 122 per 10 ha. The group of dominant species always consisted of five bird species: Sturnus vulgaris, Fringilla coelebs, Erithacus rubecula, Phylloscopus sibilatrix, Parus major.
EN
In 2010 in the City of Łódź, Central Poland, electrofishing was carried out at 15 sites in the Dobrzynka, Jasień, Olechówka, Łódka and Jasieniec Streams in the Ner/Odra system. Fourteen fish species were recorded (13 species in the Olechówka and altogether 7 species in the remaining streams), of which six were limnophilic and only two rheophilic. Sunbleak Leucaspius delineatus, gudgeon Gobio gobio and stoneloach Barbatula barbatula constituted 90% of all the fish in samples. Over 100 specimens were caught at each site in the Olechówka Stream, while only 1 -11 specimens were recorded at each of the remaining sites (except one fishless site in the Jasieniec Stream). The fish distribution was determined by water purity strongly connected with the type (combined/separate) of urban sewage system functioning in a given stream basin. The condition of ichthyofauna in 2010 was slightly better than during electrofishing conducted in 2001. The Jasień and Łódka Streams were fishless in 2001 while in 2010 several fish specimens at each site belonging to the total of 3 and 4 species, respectively were recorded. In the Olechówka, in 2010 five new species were caught and the total fish abundance was over 3 times higher than in 2001.
EN
In 2010 in the City of Łódź, Central Poland, electrofishing was carried out at 12 sites in the Miazga, Bzura, Sokołówka and Lagiewniczanka Streams in the Vistula system. Eight fish species were recorded, of which two were alien (giebel Carassius gibelio and topmouth gudgeon Pseudorasbora parva) and only two were rheophilic (ide Leuciscus idus and gudgeon Gobio gobio). Roach Rutilus rutilus and three-spined stickleback Gasterosteus aculeatus constituted 64% of all the fish in samples. Stone loach Barbatula barbatula, usually common in other similar streams, was absent. The fish distribution and abundance was significantly determined by the stream regulation. In the Sokołówka electrofishing was conducted earlier at the same six sites in 2002. Seven species were recorded in both terms; in 2010 ide (coming from stocking) was captured instead of the previously recorded crucian carp Carassius carassius. The total fish abundance was over twice lower than in 2002.
EN
In the City of Łódź there are 29 streams and rivers of various sizes, 18 of them named and 11 unnamed, whose total length is 125 km. The aim of the present study was gaining initial knowledge of the abundance and diversity of aquatic macroinvertebrates in water courses in the City of Łódź. Collected aquatic macroinvertebrates were represented by 18 taxons. The highest occurrence was recorded for Dipterans (Chironomidae) (present in all samples), Oligochaeta, Ephemeroptera and Gastropoda. The distribution of macroinvertebrates along the investigated streams varied very much. The Jasień and Łódka Streams turned out least abundant and taxonomically diverse in macroinvertebrates. The opposite were the Bzura and Łagiewniczanka Streams. It confirmed that usually the differences in macroinvertebrate distribution and diversity resulted from pollution of the running waters with domestic and industrial sewage, transforming of certain water courses into sewage-storm canals, regulation including covering of river beds and banks with concrete.
EN
In 2010 electrofishing was conducted at four sites located in the Ner River section flowing across the City of Łódź. Two species co-dominated in abundance: perch (36.1%) and roach (34.2%). The site downstream from the Stefańskiego Ponds was most abundant in fish. Among 13 species represented by almost 3 thousand specimens captured there perch and roach (36.9% and 32.6%, respectively) were dominants, while ruffe (16.5%) was a subdominant. The most human-impacted site was located downstream from the Dobrzynka Stream inflow, where no fish were caught. A comparison of the present state of fish fauna with that of monitoring studies carried out during the recent decade in the river’s section flowing across the City of Łódź indicated no significant changes in fish assemblage structure. The species composition and assemblage structure of the section is positively influenced by the recreational ponds, which feed their adjacent reaches of the river with fish. Unfortunately, in two of the sampling sites the situation of fish remains critical, which is testified to by almost total lack of them. The reason of this situation is low water quality and isolation (chemical barrier) of the upper Ner River system from the Warta River.
EN
On the basis of the so far collected and/or published data on the White Stork of central Poland (the Łódź Upland) the authors undertook an attempt to explain the spatial and tem poral distribution of breeding efficiency, population density as well as nests localization and nest distribution in relation to human settlements. The efficiency of White Stork breeding depends on biotopic conditions and interspecific competition. Precipitation in spring has a positive while precipitation and low temperatures in June a negative impact on interspecific competition. Habitat conditions of the White Stork have begun to display a constant tendency to decrease in quality, mainly due to land draining. The interspecific competition depends on biotopic conditions and on density. Optimal habitat conditions, including weather ones, may largely neutralize the impact of the intraspecific competition, which enables the population an increase in density, leading even to the appearance of aggregations and colonies. A deterioration in habitat conditions increases interspecific competition, which decreases breeding success to a lower extent than that which could be expected, caused decomposition of aggregations and decrease in the density of breeding pairs. The appearance of a nest outside of the settlement area is a result of interspecific competition.
EN
The White Stork (Ciconia ciconia) bred in the former district of Kutno in 1985 at a density of 5.33 pairs/100 km 2. The mean number of nestlings per nest occupied by a pair was 2.24 and the mean number of nestlings per nest with nestlings was 2.73. 93% of the nests were situated on trees (mainly poplar trees) and 92% were up to 100 m from buildings. Storks nesting in the eastern part of the former Kutno district show a regular distribution of nests, while those from the western part a contagious one. The mean number of nestlings was statistically significantly higher in the eastern part, which can be explained by better foraging conditions there due to many river valleys.
EN
Having analysed materials collected in the Łowicz District in 1968 1970, 1974, 1975, 1983 and 1984 the author proved the occurrence of a continuous increase in the number of nests which were not occupied by pairs and nests which had no breeding success. Since 1970 the total number of nestlings which left their nests has also been on the decrease. Between 1970 and 1975 the density of pairs calculated for 100 km2 increased from 11.37 to 14.00 and then decreased to 10.39 in 1984. Positive changes in density were preceded by a high efficiency of breeding, while negative ones by a low efficiency. Since 1970 an increase in the number of nests built on the poles of electric traction has been observed. The author has proved that in places where groupings of nests (HP) consisted of more than 5 ones and when the distances between nearest ones did not exceed 1.5 km, intraspecific competition was the most significant factor limiting the efficiency of breeding.
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