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Mass occurrence of nuisance algal species Gonyostomum semen is observed in European humic lakes since 1970s, initially in the Scandinavian countries, then in eastern, central and western part of the continent. In 2002 mass appearances of this flagellate were found in three of 12 investigated humic lakes situated in the Eastern Poland. Lakes with Gonyostomum were situated within small geographical area. The biomass of algae was usually higher than 1 mg dm⁻³ and during summer its distribution was frequently uneven with higher values found in deeper layers. Based on this research we conclude, that G. semen during its spreading on the new area had preferred 6–8 m deep and small lakes with thermal and oxygen stratification as well as with low calcium content, slightly acidic to slightly alkaline pH and moderate color of water.
The present study investigates the genetic structure of 12 roe deerCapreolus capreolus Linnaeus, 1758 population samples from Serbia, by screening a total of 334 individuals. We examined whether genetic differentiation exists in local populations in Serbia, and addressed the question whether management policies may affect genetic structure. The populations were analysed by multilocus protein electrophoresis, with 33 protein loci examined. Screening of 20 enzymes and one group of general proteins revealed polymorphism at the following 12 loci: Sdh, Mdh-1, Me-1, Idh-2, 6-Pgd-1,αGpd, Ak, Pgm-1, Pgm-2, Ca, Mpi andGpi. Among samples, the proportion of polymorphic loci varied between 3–15.2% (mean 11.9%), while the average gene diversity was in the range of 1.1–4.2%. The overall genetic differentiation was low (θ = 0.03). The comparison of two regional population groups (northern-southern, separated by the Danube River) showed an absence of genetic differentiation between regions. Gene flow was estimated at 8.96 migrants per generation, and was higher in the lowland than in the highland group. Three loci (Ca, 6-Pgd andGpd-1) showed clinal variation along a geographical gradient. Additional five alleles of four loci (Ak, Pgm-1, Gpi, 6-Pgd) showed significant spatial autocorrelation. Genetic distances were small (D = 0–0.004). Northern and southern populations clustered separately. For at least three populations game management practices provide evidence for outlying genetic parameters. The observed heterogeneity in the inbreeding level was deemed more under the influence of non-random mating strengthened by game management, than by overall selective pressure.
The influence of habitat factors on macrophytes distribution was studied along the Hron river – one of the longest Slovakian rivers (length 298 km; average flow rate – 56 m³ s⁻¹ near the outfall into the Danube) and important tributary of the Danube river. Along the river bed, 19 sections were selected according to approximately regular distances and with and without apparent industrial or agricultural influence. Each river section was 500 m in lenght, and was divided into 5 subsections with a constant length of 100 m. In each subsection, the abundance of all macrophytes was assessed using a five-level scale, from rare to very abundant (Plant Mass Estimate, PME), and habitat factors were measured or assessed. Only one side of river bed was assessed except the upper part, where plants occur across the river bed and therefore the whole river bed was assessed. PME data were transformed into “plant quantity” using the function y = x³ (y – “plant quantity”, x – PME; cf. Kohler and Janauer 1995) and their numerical derivatives were calculated for each river section. These are: the Relative Plant Mass – RPM (percentage of “plant quantity” of each species weighted by the river section length, formula (1) and the Mean Mass Total – MMT (index of mean PME of each species with regard to the full length of the river section, formula (2). Species richness of macrophytes (hydrophytes) is low; only 11 species were found. More than 50% of river sections contain only filamentous algae, Rhynchostegium riparioides (Hedw.) Cardot, and Myriophyllum spicatum L. According to the RPM, taxa can be ordered as follows: Batrachium penicillatum Dumort. (RPM ≈ 65%), Myriophyllum spicatum (RPM > 19%), filamentous algae (RPM ≈ 6%), Fontinalis antipyretica Hedw. (RPM > 5%), Rhynchostegium riparioides (RPM > 3%) and other species RPM ≈ 0.6%. Canonical correspondence analysis (forward selection) showed 6 habitat factors with significant effect on macrophyte vegetation pattern in the river: the distance from river outfall (river km), temperature and conductivity of water, the width of the river bed, bed material, and human land-use in the surrounding landscape. A direct impact of agricultural or industrial agglomerations was manifested more/less only in the increase of species diversity (H´ ranging from 0.99 to 1.28). Some macrophytes significantly react on habitat changes by changing the MMT. The MMT of filamentous algae, Batrachium penicillatum and partly Rhynchostegium riparioides, increased with altitude, distance from the outfall of the river, and flow velocity, but decreased with the width of the river, conductivity of water, average air and water temperature. An obviously contrasting trend was revealed for Myriophyllum spicatum. Fontinalis antipyretica slightly prefers colder water and Batrachium penicillatum shows a positive correlation with pH.
The purpose of the present study was to examine the relative influence of different habitat factors on otters Lutra lutra (Linnaeus, 1758) and to develop a predictive model to better understand the distribution of the otter in Denmark. During the National Otter Survey in 1991 data were collected on 19 variables which reflected aspects of habitat structure, composition, organic pollution and human disturbance. Multiple logistic regression analysis was used to estimate probabilities of the presence of otters as a function of one or more explanatory variables. Six variables (county, pH, water depth, presence of trees, bottom substrate and Saprobien-Index) were identified. In Denmark, otter habitat typically consists of water courses with depths > 1 m over a varied bottom, with pH > 7.0, Saprobien-Index on II-III to III (indicating slight organic pollution) with no trees on the banks. Some of these variables reflect highly productive waters. The use of the otter as an indicator of good water quality and/or aquatic habitat should be used with care.
Non-forest woody vegetation (scattered greenery) is currently a common feature of the rural European landscape and provides important ecosystem services. This study presents the statistically based classification of non-forest woody vegetation at the local level according to its structural characteristics mapped in the field. Using hierarchical agglomerative cluster analysis, four groups (clusters) of non-forest woody vegetation were detected. Relation of groups of non-forest woody vegetation to altitude, slope gradient and distance from settlements was found, although differences in these factors between groups are small. Moreover, differences in spatial structure in terms of landscape ecology among groups of non-forest woody vegetation were examined and considerable differences among groups were recognized when comparing basic landscape metrics. Presented classification covers unique local or sub-regional groups of non-forest woody vegetation, but it is not sufficient for the national level. For this purpose, it is advocate advised that additional data be collected and official evidence of existing non-forest woody vegetation be generated.
The study presents the results on the dynamics and structure of the litter fall in the beech stand in two years (1995 - seed year and 1996 - barren year) overgrowing the northern slopes of the "Góra Chełmowa" located in Ojców National Park in two fertility variants. The total litter fall mass during the seed year was on average 4067.3 kg/1 ha and was different by 1260.15 kg from the results obtained during the following year. The greatest part of the litter fall are leaves, which make about 67.6% of the litter fall mass during the seed year and as much as 95.9% in the following year. The fertile habitat had a stimulating effect on the litter fall biomass production such as leaves, seeds, and seed cupules.
In experiments located in Prusy (Kraków voivodship) at Wierzbica (Katowice voivodship) at the end of vegetative growth in the fall 6 empiricaly determined features characterizing young red clever plants grown in pure stand and undersown in spring barley were analysed. These were following features refering to a single plant: fresh and dry weight, the length of tops and roots, diameter of the root crown and number of shoots. Based on these features 4 indirect indicators were constructed. In 1993-1994 total of 420 plants were analysed. For direct and indirect indicators means and standard deviations were callculated taking into account the influence of given year, location and method of sowing. Least squares and phenotypic correlations between investigated features were also evaluated. In 1994 average values for analysed plant features of red clever were higher than in 1993. The effect of location (of the experiment) was not visible. Better plants were formed when red clever was undersown in spring barley than when grown in pure stand (without the cover crop). Alls features measured directly showed very high variability between these features were observed. Correlation between the fresh and dry weight need to be emphasized. Also interactions between years and method of sowing, and between location and method of sowing turned out to be significant.
W pracy omówiono rolę najważniejszych czynników siedliska jak: gleba, ukształtowanie, terenu, stosunki wodne, opady z punktu widzenia poziomu plonów. Na przykładzie wieloletnich doświadczeń polowych wykazano możliwość specjalizacji płodozmianów w kierunku zwiększenia zasiewów zbóż. Udział zbóż w strukturze zasiewów w płodozmianie na poziomie 75% obniżał plony w granicach 3-12%. Wielkość tej obniżki zależała od jakości gleb oraz doboru następstwa gatunków roślin zbożowych.
W latach 1988 - 1991 przeprowadzono badania nad wpływem nawożenia azotowego i czynników siedliskowych na wzrost roślin truskawek. W doświadczeniu badano dwie odmiany: Dukat i Senga Sengana. Zastosowano 8 kombinacji nawozowych: dwie kontrole (z obornikiem i bez obornika) oraz dawki azotu 30-60-90 kg N/ha stosowanego corocznie lub tylko w pierwszym roku badań. Kombinacje nawozowe z azotem były również z obornikiem. W wyniku przeprowadzonych badań stwierdzono, że czynniki meteorologiczne, a szczególnie mała ilość opadów, miały duży wpływ na wzrost i fenofazy roślin. Wysoki poziom nawożenia azotowego (60 i 90 kg N/ha) stosowanego corocznie oraz obornik miały dodatni wpływ na przyrost liści na roślinie, a także na wysokość roślin. Rośliny odmiany Dukat były wyższe, lecz miały mniej liści niż rośliny odmiany Senga Sengana.
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