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Abstract

The article presents the possible methods for determining biological or statistically significant differences between taxocenoses compared with respect to biodiversity. To obtain a complete description of biological differences between the compared hypothetical communities, the following indices were calculated: S (taxon richness), H (the Shannon index), Hmax (the maximum value of the Shannon index for the richness of taxa represented by the same number of individuals), Vd (a percentage value of covering the structural capacity of community, “evenness deficiency”), E (the MacArthur index - a taxon number (S) in a community for which the observed value of H equals Hmax), and Ps (a taxon richness shortage in percents). Moreover, a graphic profile method (Дд, Tj, and Lj profiles) was used for comparing the diversity of the communities. To obtain information about statistically significant differences in biodiversity between the analysed communities, rarefaction curves were applied. The curves are based on the null models and the Monte Carlo method. The rarefaction method resulted in determination of the statistical significance of the differences between taxon richness and Shannon's index values for the compared communities. The Vd and Ps indices and the profile method allowed concluding about the significance of the biological differences between taxocenoses, even when their values of Shannon's H indices were numerically similar.

Abstract

This paper assesses the effects of agricultural payments on changes in farmland bird diversity in Slovenia. Diversity was measured by Shannon index, while the impacts were estimated with the first-difference estimator on panel data for municipalities with and without special protection areas for birds. The effects of agricultural payments on farmland biodiversity require that the balance of financial instruments be taken into account when the agricultural policy is being drafted. The effects of payments in municipalities with and without special protection areas indicate the need to consider the landscape perspective and adapt schemes to landscape type while preparing the national agricultural policy.

Abstract

Cultural practices such as tillage used for crop production influence the composition of the weed seed bank in the soil. In order to investigate the effects of different tillage methods on seed bank properties, species diversity and similarity, two laboratory and greenhouse experiments were carried out as randomized complete block design with four replications in 2011. Treatments included: once tillage per year (T1), twice tillage per year (T2), more than twice tillage (T3) and no tillage (T4). Laboratory results showed that the T3 and T4 treatments had the highest and the lowest observed seeds numbers, respectively. Between the laboratory observed weed seeds, the maximum weed seed numbers were Echinochloa crus-galli and Amaranthus retroflexus in the T3 treatment, while Chenopodium album, Polygonum aviculare and Cuscuta campestris had the highest seed numbers in the T2 treatment. At the greenhouse study, Chenopodium album, Amaranthus retroflexus and Hordeum morinum in the T2 treatment were dominant species. The highest diversity was observed in the T2 treatment, and Chenopodium album and Echinochloa crus-galli were dominant species in the T2 and T3 treatments. Maximum species similarity index was achieved from the T1 and T3 treatments. Thereby this study concluded that increasing of tillage number could affect the similarity index of weed seeds and subsequently alters the weed community composition.

Abstract

The aim of this study was to present the relationship between soil properties and biodiversity indexes in upland fir (Abies alba) forest associations (Abietetum albae). Our study was conducted in six areas representing the growth conditions of upland fir forests and the research plots were located in the Roztoczański and Świętokrzyski National Parks as well as Przedbórz, Radomsko, Piotrków and Janów lubelski Forest District. on every plot, the topography was described, soil cores were examined and samples for laboratory analysis were taken. the following characteristics were determined for the soil samples: ph, c, n, ca, Mg, na and K content, particle size, exchangeable acidity, aluminum content and hydrolytic acidity. additionally, enzyme activity in the soil samples (urease and dehydrogenase) was measured. in each test area, the stand characteristics were measured (diameter at breast height and height), floristic characteristics were described and the biodiversity indexes (Shannon, Simpson and Margalef indexes) were calculated. Different soil types (gleysols, Brunic arenosols, gleyic Podzols and hyperdistric cambisols) were recorded for the investigated forest stands and the soils were categorized according to soil texture, c content, enzyme activity and different humus types (moder-mor, moder, moder-mull). the upland mixed coniferous forest sites were characterized by lower biodiversity indexes (2.6 shannon index; 0.72 simpson index; 4.9 Margalef index) while the upland mixed broadleaf forest sites showed higher indexes (3.3 Shannon index; 0.87 Simpson index; 9.4 Margalef index). The site index obtained for the fir stands confirmed these results.

Abstract

For the investigation of fish from Karkheh River, sampling was performed in a six month period from August 2014 to January 2015. All sampled fish were measured for biometrical values (length and weight). General results of the sampling and identification of the fish showed the presence of 14 species from four fish families of Cyprinidae, Mugilidae, Siluridae and Macrostomidae, out of which the Cyprinidae family were the most frequent of the sampled fish. The most significant abundance belongs to Cyprinus carpio. The fish sampled in the present study were: Liza abu, Ctenopharyngodon idella, Barbel sp., Cyprinion macrostomum, Barbus sharpeyi, Hypophthalmichthys molitrix, Barbus esocinus, Barbus barbulus, Barbus luteus, Barbus grypus, Cyprinus carpio, Silurus triostegus, Mastacembelus circumcinctus and Capoeta trutta. Shannon Index results showed that the fish biodiversity in the studyed area followed a uniform path and additionally that the considered area at the studied period has good fish biodiversity.

Abstract

The largest wastewater treatment systems include Sorbulak and Kurty reservoirs, and the small storage ponds were studied in the summer of 2017 and characterized mainly by organic pollution. Phytoplankton communities were represented by species tolerant of organic and toxic pollution. Cyanobacteria dominated in the reservoirs, and dinophyte algae were only in the Kurty Reservoir. According to the results of CCA analysis, only Cr and certain nutrients had a significant effect on the abundance of algae. A statistically positive significant association between the Shannon index and the average algal cell mass was established. The results obtained are a particular example reflecting the non-linearity of changes in plankton communities in the gradient of nutrient loading and eutrophication of aquatic ecosystems.

Abstract

Oribatid mite communities were investigated in southern Italy in litter under yew, pine and cypress trees. These mites achieved the highest density in yew and cypress litter in a park in the inland town of Caserta, and the lowest density in pine litter at the coast of Capo Vaticano. In these mite communities, only 1-4 species were abundant, so the Shannon index H’ was rather low. The density of oribatid mites, species number, and dominance structure depended greatly on the kind of litter. The most abundant and common was Zygoribatula propinqua, but the highest density in yew litter was achieved by Oribatella superbula. In oribatid mite communities, the juveniles usually dominated, but the age structure of species greatly depended on the kind of litter.

Abstract

We compared within-population variability and degree of population differentiation for neutral genetic markers (RAPDS) and eight quantitative traits in Central American populations of the endangered tree, Cedrela odorata. Whilst population genetic diversity for neutral markers (Shannon index) and quantitative traits (heritability, coefficient of additive genetic variation) were uncorrelated, both marker types revealed strong differentiation between populations from the Atlantic coast of Costa Rica and the rest of the species’ distribution. The degree of interpopulation differentiation was higher for RAPD markers (FST = 0.67 for the sampled Mesoamerican range) than for quantitative traits (QST = 0.30). Hence, the divergence in quantitative traits was lower than could have been achieved by genetic drift alone, suggesting that balancing selection for similar phenotypes in different populations of this species. Nevertheless, a comparison of pair-wise estimates of population differentiation in neutral genetic markers and quantitative traits revealed a strong positive correlation (r = 0.66) suggesting that, for C. odorata, neutral marker divergence could be used as a surrogate for adaptive gene divergence for conservation planning. The utility of this finding and suggested further work are discussed.

Abstract

Studies on environmental variables and ecological distribution of ichthyofauna assemblages were conducted in the Calabar River. Surface water and ichthyofauna were sampled in order to provide baseline or reference data on the Calabar River at present as regard its future prospects. Seasonal variation shows significant differences in surface water temperature, pH, DO, BOD, conductivity, TDS and TSS between sampling stations and insignificant differences in heavy metals such as cadmium, chromium, iron and copper between sampling stations. Twenty six species of fish fauna were identified belonging to twenty two families. Mugilidae, Clariidae, Cichlidae, Gobiidae and Sciaenidae were the most abundant for both wet and dry season, while Clupeidae, Bathyclupeidae, Carangidae and Sphyraenidae were low in the wet season but high in the dry season. Chromium, copper, surface water temperature, DO correlate significantly with the presence of E. fimbriata, B. soporator, M. sebae, C. gariepinus, M. loennbergii, C. guentheri and P. babarus. The overall values of biotic diversity indices ranged from 0.0504-0.0745 for Simpson’s Index, 2.770-3.095 for Shannon Index, 2.821-3.105 for Margalef’s Index and 0.8606-0.9498 for equitability. However, the presence of certain fish fauna in polluted and non-polluted parts of the river indicates that they could be used as potential bioindicators in assessment and biomonitoring of the river. The methods used in identifying fish diversity proved their applicability for future studies.

Results of monitoring of the population of Blumeria graminis f.sp. hordei in Latvia in 2009-2010

In 2009-2010, random samples of the causal agent of barley powdery mildew were collected in Daugavpils (south-eastern Latvia, Latgale region), Stende (north-western Latvia, Kurzeme region) and Priekuļi (north-eastern Latvia, Vidzeme region). Virulence frequency, complexity and pathotypes were calculated in the pathogen populations. Significant differences of virulence detected by the genes Va1, Va3 and Va13 occurred among samples of the pathogen population collected in different parts of Latvia. Nei index, Müller's index, Kosman index, Shannon index and Simpson index showed considerably higher diversity in Daugavpils and Stende during 2009-2010. In Daugavpils, the population of Blumeria graminis f.sp. hordei was particularly characterised by high diversity.