Search

A comparative study was undertaken to adopt and evaluate a radiocarbon (14C) preparation procedure for accelerator mass spectrometry (AMS) measurements of cremated bones at our laboratory, including different types of archaeological samples (cremated bone, bone, charcoal, charred grain). All 14C analyses were performed using the EnvironMICADAS AMS instrument at the Hertelendi Laboratory of Environmental Studies (HEKAL) and the ancillary analyses were also performed at the Institute for Nuclear Research (ATOMKI). After the physical and chemical cleaning of cremated bones, CO2 was extracted by acid hydrolysis followed by sealed-tube graphitization and 14C measurement. The supplementary δ13C measurements were also performed on CO2 gas while FTIR was measured on the powder fraction. Based on the FTIR and 14C analyses, our chemical pretreatment protocol was successful in removing contamination from the samples. Good reproducibility was obtained for the 0.2–0.3 mm fraction of blind-tested cremated samples and a maximum age difference of only 150 yr was found for the remaining case studies. This confirms the reliability of our procedure for 14C dating of cremated bones. However, in one case study, the age difference of 300 yr between two cremated fragments originating from the same urn shows that other processes affecting the cremated samples in the post-burial environment can substantially influence the 14C age, so caution must be exercised.

This study summarizes the results of radiocarbon dating and age-depth modelling in four mountain lakes (Brazi, Gales, Bucura and Lia) in the Retezat Mountains. Altogether 69 AMS 14 C measurements were performed on these deposits, mostly on terrestrial plant macrofossils. In several cases, plant macrofossils, aquatic animal remains (Cladoceran eggs) and bulk sediment were measured from the same depth allowing for the comparison of various sediment components in terms of their dating potential. Age-depth models were developed using both Bayesian modelling with the BACON and smooth spline curve fitting with the CLAM software. In this study Bayesian models are applied to identify outlier 14 C dates, while smooth spline models are used to model sediment accumulation age-depth relations, as these are more likely to follow natural deposition time changes of lake sediments. Changes in sediment deposition times (DT) in relation to catchment size and climate are also studied. DT varied considerably in the late glacial (LG) part of the records. The sediment sequence characterised by high deposition rates during the late glacial (DT maximum around 100–110 years cm −1 ) was defined by small catchment size (Lake Brazi, 6 ha; surface area: 0.5 ha). In contrast, much slower LG sediment deposition in the southern slope lake characterised by large catchment area (Lake Lia, 171 ha, 20 years cm −1 ), principally reflecting strong erosion in these catchment areas at times when vegetation cover was scarce. Holocene was characterised again by variable DT values, but only Lake Gales showed extreme values: 62–110 years between 10,900 and 6050 cal yr BP, followed by much slower sediment deposition in the last 6000 years (av. 29 years cm −1 ). Generally, sediment deposition times were largely dependent on the stability and vegetation cover of the slope in the case of high altitude deep lakes, while lower altitude, shallow lakes showed slower sediment deposition time in the early and mid-Holocene, when summer insolation was higher than today. This reflects that in these shallow lakes in-lake organic production probably increased with summer insolation, which was a significant driver in the rate of deposition.

We tested the effect of urbanization on air pollution based on the chlorophyll-a content of Celtis occidentalis leaves along an urbanization gradient (urban, suburban and rural areas) in Debrecen, Hungary. Chlorophyll-a content of Celtis occidentalis, Acer campestre, and Corylus avellana were compared to test which species is the most useful to study the effects of urbanization. Furthermore, the effects of washing solutions (distilled water, tap water, and rainwater) on chlorophyll-a content of tree leaves were also tested during sample preparation. Chlorophyll-a was extracted from leaf samples with acetone, and it was measured using a spectrophotometer. Along the urbanization gradient, chlorophyll-a content of C. occidentalis leaves was the lowest in the urban area; thus, this species proved to be an effective indicator of anthropogenic emission load. Differences were not significant among species in the suburban and rural areas, where the level of air pollution was moderate. We found that effects of the washing solutions on chlorophyll-a content did not differ significantly from each other. Thus, tap water can be used safely to clean the leaf surface, without significant influence on chlorophyll-a. Our study demonstrated that the chlorophyll-a content of leaves was a useful indicator to assess the level of air pollution.

The reproducibility of extraction of residues from spiked soil samples and from soils containing incurred residues was tested with 14C-labeled test compounds of different physical-chemical properties. Nearly 100% of the compounds added to the sample before extraction could be recovered with an average reproducibility relative standard deviation (CV) of 5.4%. The additional steps of the determination process (cleanup, evaporation, etc.) contributed to the major part of the variability of the results (CV = 10–20%). The incurred residues were most efficiently extracted with acetone for 30 min followed by the mixture of acetone/ethyl acetate 1:1 for additional 30 min. However, they could only be recovered at various extent (64–90% of total residues), underlying the importance of testing the efficiency of extraction. The residues were identified and quantified by gas chromatography applying thermionic detector. The performance parameters of the method complied with the international method validation g...

Background. The Amur sleeper, Perccottus glenii Dybowski, 1877, is the most invasive alien fish species in the native aquatic communities in central Europe. Although the accelerated invasion of P. glenii has been well documented, there is little information on the ecological and growth parameters of non-native populations in this region. The aim of this study was to describe the growth features of the population of P. glenii in a shallow oxbow lake in the Carpathian Basin. Materials and methods. Our study sample consisted of 1239 individuals (628 ♂ + 611 ♀) collected from an oxbow lake near the Tisza River in the same month for three years (2013–2015). The length, weight, age structure, sex-dependent growth rate, and the condition factor of the collected specimens were determined. Results. The sex ratio was 0.49 (♀ ÷ (♀ + ♂)). The standard length and weight of the collected P. glenii specimens ranged from 20.7 to 127.7 mm and from 0.3 to 75.8 g, respectively. The length–weight relations (SL–W) were allometrically negative for the males (W = 3.2 × 10–5SL2.960), females (W = 3.8 × 10–5SL2.921), and both sexes (W = 3.5 × 10–5SL2.940), without significant differences between males and females. According to the length-frequency analysis, five age groups were differentiated. The von Bertalanffy growth models were L∞ = 138.87 mm, k = 0.21, t0 = –0.54 (♂), L∞ = 174.21 mm, k = 0.17, t0 = –0.33 (♀), L∞ = 154.01 mm, k = 0.19, t0 = –0.45 (♂ + ♀). The growth performance parameters were Ф′ = 3.61 (♂), Ф′ = 3.71 (♀), Ф′ = 3.65 (♂ + ♀), respectively. Conclusion. Due to unequal investment in reproduction, there was a significant difference in the growth rate between males and females. The literature data showed that invasive gobies and odontobutids (e.g., P. glenii) exhibit more opportunistic reproduction strategy in newly colonized areas, which may contribute to the invasion success. This strategy (e.g., earlier maturation, longer spawning period, etc.) results in slower growth rate due to energetic trade-off between reproduction and somatic growth. The observed growth rate of invasive Amur sleeper population (especially in the older age groups) was slower than that of native and more established naturalized populations in Eurasia.

We have developed a chromium speciation and preconcentration method with the use of the graphite furnace atomic absorption spectrometry (GFAAS) technique. This method is based on single-drop microextraction (SDME) technique. Nowadays the microextractions have become popular, because low amount of organic solvent needs to be used for the separation. The sample was introduced into the extraction cell with a single chloroform droplet. For the separation and enrichment of chromium species, an ion-pair forming compound was used. After the extraction, the chromium content of the droplet was determined by GFAAS. The analytical sensitivity of the standard SDME technique was improved by increasing the volume of organic phase and by sample recirculation. Because of the increased contact area and the developed extraction device, the stability of droplet was markedly increased. As an application we have determined the Cr(VI) content of sea water by the GFAAS technique using these separation/enrichment methods. Under the optimized extraction conditions, the linear range, detection limit (S/N = 3) and precision (RSD, n = 3) for Cr(VI) were 0.14 – 5.00 μg/L, 0.042 μg/L, and ≤ 3.0%, respectively. The advantages of this method are the following: cost efficiency, the high enrichment of chromium species and easy usage with the GFAAS technique. Therefore the concentration of the chromium species can be determined at the ng/L level.

The involvement of ecological theory in habitat restoration has significantly increased in the past decade. However, despite the fact that the field of restoration ecology has grown academically strong in recent years, there are still visible gaps between the advancing discipline of theoretical ecology and current approaches of habitat restoration. We propose bridging these gaps by linking recent developments in theoretical plant ecology with the main questions every restoration practitioner should ask, namely: Q1) How to identify target species and baseline conditions for restoration of the selected habitat?; Q2) When can one count on spontaneous dispersal and when are additional efforts required for facilitating dispersal of desired species?; Q3) Which factors determine the successful establishment of target species and assembly of target communities?; and Q4) What time-scale needs to be considered for the evaluation of species colonisation and restoration success? Knowledge and experience accumulated in practical restoration can considerably benefit theoretical ecology for example by improving the understanding on (i) temporal changes in community, (ii) species assembly, (iii) species dispersal and establishment and (iv) landscape-scale dynamics of biodiversity. We emphasise that to improve joint thinking of practical restoration and theoretical ecology, restoration-problem-driven theoretical research is necessary. We suggest either (i) to translate and link the current findings of theoretical ecology to restoration strategies; and/or (ii) to summarise practical restoration needs by formulation of questions and testable hypotheses based on theory.

KA

Several hundred tons of windblown dust material are lifted into the atmosphere and are transported every year from Saharan dust source areas towards Europe having an important climatic and other environmental effect also on distant areas. According to the systematic observations of modern Saharan dust events, it can be stated that dust deflated from North African source areas is a significant constituent of the atmosphere of the Carpathian Basin and Saharan dust deposition events are identifiable several times in a year. Dust episodes are connected to distinct meteorological situations, which are also the determining factors of the different kinds of depositional mechanisms. By using the adjusted values of dust deposition simulations of numerical models, the annual Saharan dust flux can be set into the range of 3.2–5.4 g/m2/y. Based on the results of past mass accumulation rates calculated from stratigraphic and sedimentary data of loess–paleosol sequences, the relative contribution of Saharan dust to interglacial paleosol material was quantified. According to these calculations, North African exotic dust material can represent 20–30% of clay and fine silt-sized soil components of interglacial paleosols in the Carpathian Basin. The syngenetic contribution of external aeolian dust material is capable to modify physicochemical properties of soils and hereby the paleoclimatic interpretation of these pedogene stratigraphic units.

LB

To investigate treeline and timberline dynamics in the Retezat Mountains (Romanian Carpathians), late glacial and Holocene sediment sequences from four lakes were studied. The south and north slopes of the mountain range were compared using two lakes from the north flank (Lake Brazi, 1740 m a.s.l. and Lake Gales, 1990 m a.s.l) and two from the south flank (Lake Lia, 1910 m a.s.l. and Lake Bucura, 2040 m a.s.l.). Macrofossil and stomata analyses were performed to assess changes in the local vegetation, supplemented by pollen, charcoal and loss-on-ignition analyses. Our results show that treeline reached Lake Brazi on the northern side during the late glacial (ca. 14,000 cal yr BP) and then Lake Gales between 11,000 and 10,800 cal yr BP. During the early Holocene the upper limit of closed forest, the timberline, reached and passed Lake Brazi and has stayed above it since, but it has never reached Lake Gales at 1990 m a.s.l. The expansion of Larix decidua in the late glacialand early Holocene around Lake Brazi is unique. Stomata and macrofossils of Abies alba are also more abundant in the northern records. On the southern flank, treeline reached Lake Lia at around 12,000 cal yr BP, and was either very close to or at the elevation of Lake Bucura between ca. 8600 and 3000 cal yr BP. Timberline reached Lake Lia at ca. 8000 cal yr BP, some 3000 years after Lake Brazi, only 170 m lower on the north slope. Local fire events delayed the advance of timberline around Lake Lia in the early Holocene in a dry continental climate. The surrounding forest was dominated by Picea abies with individuals of Pinus cembra and stands of P. mugo until about 3000 cal yr BP when timberline retreated below the lake. Maximum elevation of timberline was attained between ca. 8000 and 3000 cal yr BP, after which it descended in response to climate cooling. Regional climate change appears to be the main driver of treeline dynamics, but it was modified by local climatic differences due to slope aspect. The first signs of human disturbance appeared ca. 4200 cal yr BP, when naturally open areas were used as alpine pastures. Human impact in the treeline ecotone, mainly burning and grazing, was intensified after ca. 2600 cal yr BP, contributing to the widening of the ecotone and the lowering of the timberline.

1.Floral deception is widespread in orchids, with more than one third of the species being pollinated this way. The evolutionary success of deceptive orchids is puzzling, as species employing this strategy are thought to have low reproductive success (less flowers yielding fruits) because of low pollination rates. However, direct measurements of total seed production in orchids – which is a better measure of reproductive success – are scarce due to the extremely small size of their seeds. 2.Here, we quantified seed numbers in 1,015 fruits belonging to 48 orchid species from the Pannonian ecoregion (central Europe) and obtained fruit-set and thousand-seed weight data for these species from the literature. We used phylogenetic comparative methods to test the hypothesis that deceptive species should compensate for their lower fruit-set by having either more flowers, larger seeds or more seeds in a fruit. 3.Similarly to previous studies, we found that deceptive orchids have substantially lower fruits-set than nectar-rewarding ones. Also, we found that deceptive species have more seeds in a fruit but not more flowers or larger seeds compared to nectar-rewarding ones. Based on our results, deceptive species compensate for their lower fruit-set by having higher seed numbers per fruit. As a consequence, their seed numbers per shoot do not differ from that of nectar-rewarding ones. 4.Together with other benefits of deceptive pollination (e.g. lower energy expenditure due to the lack of nectar production and higher genetic variability due to decreased probability of geitonogamous pollination), our results can explain why deceptive strategies are so widespread in the orchid family. 5.Synthesis. Our results indicate that deceptive orchids can compensate for their lower fruit-set by having more (but not larger) seeds in a fruit than rewarding species. These findings highlight possible ways in which plants can increase their reproductive success in face of pollinator limitation. We emphasize that fruit-set in itself is an inappropriate measure of the reproductive success of orchids – the total number of seeds per shoot is a much better approximation.

Ecosystem management often aims to maintain a diversity of habitats to benefit a large number of species within a landscape. We studied the effects of wetland management by low-intensity cattle-grazing and late-summer burning on marsh vegetation and globally declining anuran amphibians (frogs and toads) in a previously homogeneous reedbed. Burning effectively removed old reed and increased the variability of reed cover and marsh vegetation by the next spring. However, reed grew back strong in areas burned 2 or 3 years before the study, indicating that fire rejuvenates reedbeds. In contrast, cattle-grazing kept reed cover homogeneously low and created open water surfaces. The number of amphibian species and individuals decreased with mean reed cover and old reed density, and increased with variability in reed cover. Correspondingly, amphibian richness and counts were greatest in newly burned areas the next spring. In contrast, a year later, richness and counts were greatest in grazed-only areas, with large decreases in newly burned and control areas. Our results suggest that combined management with grazing and burning can create different habitat patches, some of which will be optimal for amphibians in one year, whereas other patches may become suitable in a subsequent year when successional changes alter previously optimal patches. To maximise optimal habitats, mosaic management should repeat burning once every 2 or 3 years in a rotational manner, and also maintain low-intensity cattle-grazing, which controls reeds and benefits amphibians more sustainably. Our study supports spatiotemporally varied management to facilitate habitat heterogeneity and complexity in dynamic landscapes.

Creating plantations after clear-cutting of native forests is a serious risk for biodiversity. Rove beetles were collected by litter sifting in non-native plantations (black locust, Scots pine, red oak), in native oak plantation and mature oak forest as control. We hypothesised that diversity and composition of the rove beetles in the mature forest would be different from those in the plantations. We expected that reforestation with native species would have less harmful effects on rove beetles than reforestation with non-native species. In accordance with our hypotheses the overall number of rove beetle individuals and species, as well as the diversity of hygrophilous and decaying material dependent rove beetles were significantly lower in the plantations than in the mature oak forest. However, the overall species richness and the diversity of hygrophilous and decaying material dependent rove beetles were significantly higher in the native plantation compared to the non-native ones. There was no significant correlation between the diversity of these rove beetles and the soil moisture and decaying woody materials as limiting resources; thus, our study did not support the resource quantity hypothesis. The cover of herbs and shrubs, the soil temperature and soil pH were the most important factors controlling the diversity of rove beetles. Our results suggest that reforestation with native tree species provides more suitable habitat for rove beetles than non-native ones. However, it seems that rove beetle assemblages did not recover even after 40 years of reforestation with native tree species due to their specific ecological demands.

The occurrence and spread of halophilic diatom taxa in freshwater lotic ecosystems are influenced both by natural processes and anthropogenic pollution. Diatom assemblages were regularly monitored in lowland lotic systems in Hungary (Central Europe) during the unusually dry year of 2012. Highly pronounced changes in diatom composition were observed from spring to autumn. Halophilic taxa (especially Nitzschia sensu lato species) appeared in the dry autumn. In addition, the total relative abundances of halophilic species also increased up to autumn. Abundance of Nitzschia cf. lorenziana and Nitzschia tryblionella showed a positive correlation with chloride and phosphate concentration, while that of other taxa like Tryblionella apiculata or Tryblionella calida showed a positive correlation with the concentration of nitrate. Our findings clearly demonstrated that these halophilic and mesohalophilic diatom taxa were sensitive indicators of even short-term changes in lowland lotic ecosystems, such as the increasing salt concentration from spring to autumn caused by the lack of rainfall and/or environmental loads.

Understanding the distribution of biotic diversity across various spatial scales and environmental gradients is important from fundamental, practical and conservation biological aspects. We applied a hierarchical diversity partitioning framework to quantify the variability of sample level α- and β1-diversity, and environment related β2-diversity of benthic chironomid assemblages within and among a priori defined habitat types, and along the gradients of individual environmental factors in a large and shallow lake (Lake Balaton, Hungary). Taxon richness (both additive and multiplicative) and Shannon index based diversity approaches yielded highly concordant results. The α-diversity was much lower and β1-diversity higher than predicted by null model and both measures varied substantially among habitat types and along most individual environmental gradients. The β2-diversity indicated a marked variability of taxon (identified at species to genus level) pool among habitat types and higher than predicted taxon turnover along all examined environmental gradients. Moreover, the observed β2-diversity varied greatly among individual environmental gradients. The difference between the expected and observed β2-diversity values suggests that taxon turnover was most influential (in decreasing order) along the algae coverage gradient, the lake bed substratum gradient and the macrophyte coverage gradient among others. We argue that within-lake environmental heterogeneity and its effect on the taxon richness should receive more attention in biodiversity assessment and conservation. Management could benefit from the identification of within lake gradients along which taxonomic turnover maximizes.

The gut contents of filter-feeding fish often contain considerable amounts of viable phytoplankton cells; thus, these animals can act as vectors in the horizontal and vertical transport of algae. In this study, the potential role of the introduced filter-feeding Asian carps (hybrids of silver carp Hypophthalmichthys molitrix and bighead carp H. nobilis) in algal dispersion was studied in the oligo-mesotrophic Lake Balaton (Hungary). We examined the algal composition in the lake water, gut contents (foregut and hindgut), and occasionally in the filtered suspensions collected directly from the gill rakers (filtering apparatus) of fish. Microscopic analyses revealed that the phytoplankton composition of the ingested food differed considerably from what we found in the lake water. Cryptophytes, dinoflagellates, and euglenophytes were observed in both the lake water and foregut samples but were absent in the hindgut samples. However, in the cultured hindgut samples, we found viable cells of several phytoplankton taxa (e.g., diatoms, blue-greens, desmids, volvocalean and chlorococcalean green algae), which managed to survive the physical and chemical digestion. These results imply that the presence of these filter-feeding fish can alter the phytoplankton species composition and promote the dominance of taxa that are able to resist digestion.

Comprehensive atmospheric studies have demonstrated that carbonaceous particles are one of the main components of atmospheric aerosols over Europe. The aim of our study was to establish an automated elemental analyser interfaced to a stable isotope mass spectrometer (EA-IRMS) method at the Hertelendi Laboratory of Environmental Studies (HEKAL), as a suitable method of quantification of total carbon mass in individual PM2.5 aerosol samples. Total carbon (TC) mass and simultaneous stable isotopic ratios were determined for both test standard and genuine aerosol samples. Finally, the results were compared to the ones obtained independently by an alternative sealed tube combustion method developed previously at HEKAL. The TC recovery tests of standard material prepared by the sealed tube method confirmed at least a carbon recovery yield of 92% for a broad range of carbon mass (100–2000 μg). The stable isotopic results confirmed that sealed tube method is reproducible and suitable to be used as a reference to verify our new EA-IRMS method. The EA-IRMS TC measurements of genuine aerosols gave on average 3% higher carbon recovery yield, relative to the uncorrected results of the sealed tube method. The comparison of the stable isotopic results by the two methods for aerosols also showed minimal differences. Consequently, the possibility of simultaneous TC and stable isotopic analyses makes the EA-IRMS method a very attractive alternative for continuous measurement of aerosols, with an accuracy and reliability similar to other commercial devices.

LB

Remains of aquatic biota preserved in mountain lake sediments provide an excellent tool to study lake ecosystem responses to past climate change. In the PROLONG project a multi-proxy study was performed on sediments of glacier-formed lakes from the Retezat Mountains, Southern Carpathians (Romania). The studied lakes (Lake Brazi and Gales) are situated on the northern slope of the mountain at different altitudes (1740 m and 1990 m a.s.l.). Our main objectives were 1) to describe the main limnological changes in these lakes during the last ca. 15,000 years and 2) to summarize the environmental history of the studied lakes based on taxonomical and functional patterns of the biological proxies. For this synthesis we used the results of diatom and chironomid analyses, and indirect biotic and abiotic parameters, including sediment organic matter (LOI) content, geochemical element concentrations (Al, Ca, S, Sr) and biogenic silica content. Using multivariate numerical approaches we analysed changes in the assemblage structure of siliceous algae and chironomids, compared temporal patterns among proxies, examined the relationship between potential driving factors, chironomid and diatom assemblage changes and identified paleolimnological phases of the lake successions. Changes in assemblage composition and aquatic ecosystem state apparently followed summer insolation, local climatic conditions and local productivity changes driven by these. Diatom and chironomid assemblages generally changed in a similar direction and at a similar time within a lake, but differed to some extent between Lake Brazi and Gales. At both lakes the strongest variations were observed in the Late Glacial and the first half of the Holocene. The strongest Holocene assemblage changes took place in the earliest Holocene in Lake Brazi, but extended into the mid-Holocene in Lake Gales, following long-term insolation changes and climatic changes. In addition, three common zone boundaries were identified: at ca. 14,200 and at ca. 6500 cal yr BP for every records and at ca. 3100 cal yr BP for diatom records in both of the lakes and for the chironomid record of Lake Brazi. This multi-proxy synthesis provides comprehensive data that increase our understanding of the past variability of lake ecosystem functioning and biodiversity in East-Central Europe.

The vertical distribution of soil organic carbon (SOC) with depth and its horizontal pattern is influenced by the topography and relief of the surface, due to lateral redistribution of soil material along slopes. Spatial and temproral variability of these changes is frequently due to human impacts on the landscape. In our study, the results of these processes were studied in detail in a small sub-catchment in a forested hillslope section using radiocarbon (14C) dating of SOC and embedded datable material (charcoal, artifacts) from soil profiles with colluvial accumulations. Events with accelerated material redistribution could be identified as an accumulation of a 40-cm-thick colluvial layer between cal BC 410–360 (2σ) and cal AD 430–580 (2σ). Later colluvial deposition resulted in thinner accumulations (cal AD 1120–1220 [2σ] 30 cm; cal AD 1810–1920 [2σ] 21 cm). As the earliest human impact, we found soil transformation from cal BC 1290–1130 (2σ). The depth-age model for SOC compiled according to the average SOC age and its depth showed different characteristics on middle-slope and down-slope position, with rates of 48.0 yr×cm–1 and 22.0 yr×cm–1 respectively, which indicates the importance of topographic position of soils in SOC redistribution processes.

The Middle to Upper Palaeolithic transition is one of the crucial periods of change in the prehistory of Europe due to the full emergence, continent-wide, of modern human lithic technologies, and detrimental of Neanderthal survival. Knowledge about the transition is growing, however, the evidence for cultural and technological developments for the Middle Palaeolithic in the Carpathian – Lower Danube Basin is still rather sparse. Here we discuss latest findings arising from a chronological investigation of Middle Palaeolithic assemblages within the Varghis karst, Eastern Transylvania, Romania. Combining our first chronological results with information from previous excavations, we can distinguish two main stages of habitation (albeit Middle Palaeolithic lithics and faunal remains appear scattered throughout the investigated profile) within the Abri 122 rock shelter. In order to augment the typological cultural considerations, we applied direct radiocarbon dating on bones and charcoal from within the occupation layers. Radiocarbon dating of bones suggests that the Middle Palaeolithic sequence is older than the upper dating limit of the method, whereas direct luminescence ages on the lowermost productive horizon and immediately above it indicate surprisingly old ages of ca. 106–141 ka (OSL – optically stimulated) or 99–174 ka (IRSL – infrared stimulated). Multiple-protocol dating of charcoal found within the two habitation layers produced ages >38 14 C ka BP, also suggesting that the lowermost lithic-rich horizon pertains to the Middle Palaeolithic industries. Overall, the recovered lithics, currently forming one of the most significant collections for Romania, are fully consistent with two main habitation phases connected to Middle Palaeolithic cultural affinities. The occurrence of a volcanic ash layer within Ursului Cave and originating from the Ciomadul volcanic complex (Carpathians) is first reported here. Recently dated to ∼ ≥ 43 (−50) ka, it might represent an important marker horizon, providing that it is identified within other Palaeolithic cave assemblages.

In intensively used landscapes, remnant grassland fragments are often restricted to places unsuitable for agricultural cultivation. Such refuges are the ancient burial mounds called “kurgans,” which are typical landscape elements of the Eurasian steppe and forest steppe zone. Due to their hill‐like shape, loose soil structure and undisturbed status kurgans provide proper habitats for burrowing mammals. Accordingly, grassland vegetation on kurgans is often exposed to bioturbation, which can influence the habitat structure and plant species pool. In our study, we explored the effect of fox burrows and landscape context on the habitat properties and vegetation composition of small landscape elements, using kurgans as model habitats. We surveyed the vegetation of fox burrows and that of the surrounding grassland on five kurgans situated in cleared landscapes surrounded by arable lands and five kurgans in complex landscapes surrounded by grazed grasslands. We recorded the percentage cover of vascular plants, the amount of litter, and soil moisture content in twelve 0.5 m × 0.5 m plots per kurgan, in a total of 120 plots. We found that foxes considerably transformed habitat conditions and created microhabitats by changing the soil nutrient availability and reducing total vegetation cover and litter. Several grassland specialist species, mostly grasses (Agropyron cristatum, Elymus hispidus, and Stipa capillata) established in the newly created microhabitats, although the cover of noxious species was also considerable. We found that landscape context influenced the sort of species which could establish on kurgans by affecting the available species pool and soil moisture. Our results revealed that foxes act as ecosystem engineers on kurgans by transforming abiotic and biotic conditions by burrowing. Their engineering activity maintains disturbance‐dependent components of dry grasslands and increases local environmental heterogeneity.

For risk assessment of potentially toxic element (PTE) pollution of sediments and soils the fractionation by sequential extraction procedures are applied which require longtime leaching-shaking periods to achieve the dissolution equilibria. In this work an attempt is described for reduction the duration these leaching-shaking periods of the sequential extraction procedure proposed by Community Bureau of Reference (BCR) in 1993 by application of ultrasonic treatment. The fractionation of PTE content of BCR 701 certified reference sample was performed in three experiments: “A” experiment was the control, all extraction steps were performed with 16 hours shaking according to the BCR prescription; “B” experiment: in each extraction step was applied 1 hour preliminary ultrasonic treatment and after this 1 hour shaking; “C” experiment: only 1 hour ultrasonic treatment and no shaking was applied. It was experienced that by ultrasonic treatment can be efficiently increased the rate of dissolution when constant temperature of assisting medium was kept. 77% and 63% of element content extractable with the control “A” experiment can be extracted in “B” and “C” experiments, respectively. To achieve the 100% efficiency further experiments are in process.

LB

KA

We studied dragonfly assemblages in the Ukrainian section of the River Tisza, which still shows several natural (unregulated) properties. In 2010 and 2011 larvae and exuviae were collected in the vicinity of the villages Vilok (Вилок, Tiszaujlak), Nove Szelo (Нове Cело, Tiszaujhely), Tiszobikeny (Тисабикень, Tiszabokeny) and of the towns Vinohragyiv (Виноградiв, Nagyszőlős) and Huszt (Хуст, Huszt). We collected our samples from 8 sites in the main channel, 2 sites in side channels and 3 sites in two dead channels. We collected 255 larvae and 1587 exuviae, from which 8 species of dragonflies were identified [Gomphus vulgatissimus (Linnaeus, 1758), Stylurus flavipes (Charpentier, 1825), Onychogomphus forcipatus (Linnaeus, 1758), Ophiogomphus cecilia (Fourcroy, 1785), Somatochlora metallica (van der Linden, 1825), Calopteryx splendens (Harris, 1782), Platycnemis pennipes (Pallas, 1771), and Sympecma fusca (van der Linden, 1820)]. We compared the species composition of dragonflies in the three habitats. In the case of larvae in the main channel G. vulgatissimus (48.0%), C. splendens (29.6%) and O. forcipatus (20.8%) dominated, while in the dead channels C. splendens (49.5%) and P. pennipes (23.7%) were found most frequently. In the side channels G. vulgatissimus, O. forcipatus and C. splendens were the most frequent species. S. flavipes appeared only in the main and side channels, while S. metallica and S. fusca were only detected in the dead channels.

Urban areas are radically growing worldwide, causing changes in biodiversity and natural habitats. We studied the effects of urbanisation on millipede (Diplopoda) assemblages along a forested rural–suburban–urban gradient in Hungary. We tested four hypotheses: (1) intermediate disturbance hypothesis, suggesting that millipedes are the most diverse in the suburban area; (2) habitat specialist hypothesis, assuming that the number of forest specialist species decline along the rural–suburban–urban gradient; (3) synanthropic species hypothesis, suggesting that the number of synanthropic species increase along the rural–suburban–urban gradient; and (4) mean body size hypothesis, assuming that average millipede size is decreasing from the rural area towards the urban one. We studied the effects of relevant environmental factors on the abundance of millipedes. The number of millipede individuals, species richness and diversity were significantly higher in the suburban area than in the rural and urban ones, supporting the intermediate disturbance hypothesis. The ratio of forest specialist millipede individuals and species decreased significantly along the rural–urban gradient, while the ratio of synanthropic millipede individuals and species increased significantly along the gradient. The average body size of millipedes was significantly lower in the urban area compared to the rural and suburban ones. Multivariate methods revealed changes in species composition along the rural–urban gradient. Canonical correspondence analysis demonstrated that temperature, amount of decaying wood, concentration of zinc and calcium and pH explained significant proportion of the variation in millipedes’ abundance. Our results confirmed that the environmental factors and the composition of the millipede assemblages changed remarkably along the rural–suburban–urban gradient.

Novel ecosystems formed by invasive plants provide a good opportunity to get insight into early dynamics and pattern formation of these ecosystems. The invasive black locust as host plant, Bruchophagus robiniae as host-specific seed predator and its parasitoids were the components of the studied tritrophic system. To investigate disturbance-driven dynamics of this system we created seed-vacated host plant patches in a field experiment. We removed all pods from selected patches of black locust resulting in an induced local extinction of seed predators and their parasitoids. We hypothesized that disturbance enhances top-down control by parasitoids; this enhanced top-down control decreases seed predation, facilitating the host plant's spread. We found that disturbance modified only parasitism after controlling with year effect: in vacated patches median parasitism was higher than in control patches. Seed predation exceeded its initial level in vacated patches in the third year after the disturbance, but in the fourth year it dropped again presumably due to the strong top-down control. Our findings also suggested that the seed predator was also affected by the bottom-up control of its host plant's density. We found that in the studied new ecosystem the top-down control was strengthened by the disturbance. Since the host plant of the tritrophic system is an invasive species, partial habitat disturbance of such species may increase the severity of parasitoid top-down control, which may reduce seed predation by the herbivores.

We tested the suitability of Salix viminalis for phytoextraction with the analysis of selected elements in soil, root, and leaf, and by visual tree condition assessment in an area with varying levels of contamination. Bioconcentration factor (BCF) and translocation factor (TF) were used to assess the phytoextraction potential of willows. The middle part of the study area was strongly contaminated, while the northern and southern parts were moderately contaminated. We found increasing element concentrations toward deeper layers. Mean concentrations of elements in roots were similar among the three parts, while in leaves the highest concentrations were found in the strongly contaminated part of the study area. Tree condition scores were the lowest in the strongly contaminated part of the study area, which was caused by Al, Ca, K, Mg, Ni, Sr, and Zn concentration. These elements induced leaf disease and leaf feeders. The highest BCF values were found for Cu, Fe, Mn, and Zn in root, and for Cd and Zn in leaves, indicating that S. viminalis had high accumulation potential of these elements. Furthermore, TF values were high for Cd, Mn, Sr, and Zn. Our results also demonstrated that soil element composition has major influence on the condition of S. viminalis individuals. Furthermore, visual condition assessment was found to be a useful tool to assess the phytoextraction potential of trees.

Summary Morphometric-based condition indices are widely used to assess proximate body composition and, collaterally, feeding and living conditions of fish. However, the exact relationship between condition indices and proximate body composition of fish and its relatedness to life history traits and seasonality has yet to be fully explored. Therefore, the aim of this study was to examine how the Fulton's condition factor (K-factor) is related to the chemical composition (i.e. lipid, protein, water and carbon content, and molar carbon : nitrogen ratio), length and gonadal development of fish, and how these relationships are influenced by gender and seasonality in three freshwater fish species: Amur sleeper (Perccottus glenii), pumpkinseed (Lepomis gibbosus) and rudd (Scardinius erythrophthalmus). It was found that the strength and direction of association between the K-factor and proximate body composition can vary markedly among fish species. The K-factor correlated positively with gonadal development in pumpkinseed and Amur sleeper, while no such relationship existed in rudd. Condition factor can be a reliable measure of lipid content; however, the relationship was stronger in species with higher and more variable lipid contents. Moreover, a striking and consistently negative linkage was found between the K-factor and water content of the fish body, which corresponds to the findings of several other studies. In turn, any relationship between the K-factor and the protein content of fish was not detected. Gender seemed to exert a negligible effect on the relationship between the K-factor and proximate body composition, while seasonal variance was obvious in most relationships.

Forest edges are essential to the maintenance of biodiversity at the landscape level. according to the edge effect hypothesis, diversity is higher in an edge than in adjacent areas. We tested the edge effect hypothesis for carabids and staphylinids in an oak forest- forest edge-grassland complex in the Hajdusag Landscape Protection area (Hungary). The habitat types were as follows: (1) a closed oak forest with shrubs and herbaceous plants, (2) a forest edge with extensive ground vegetation and shrub cover and (3) grassland with dense herbaceous vegetation. We collected data from 60 pitfall traps (2 spatial replicates × 3 habitats × 10 traps). The gLM results showed that the species richness of carabids was higher at the edge of the forest than in the grassland and forest interior; the number of carabid individuals was highest in the grassland. The number of staphylinids and their species richness were significantly lower in the grassland than in the forest edge and interior. The results of principal coordinates analysis showed that the assemblages of both taxa in the forest edge and interior were separated from the assemblage in the grassland area. There were significant characteristic species for the edge habitat, as revealed by the IndVal (indicator species analysis) method. our findings suggest that forest edges play a vital role in the maintenance of the diversity of carabid and staphylinid assemblages.

Enzymes are considered to be a key soil component catalysing important transformations related to decomposition and nutrient turnover, and their activity in soil can be used as a measure of soil health. As part of the Sikfőkut DIRT (Detritus Input and Removal Treatments) Project in a temperate deciduous forest in northern Hungary, we examined the extent to which enzyme activity in soil is influenced by both the quality and quantity of plant detrital inputs. DIRT treatments include doubling of leaf litter and woody debris inputs as well as removal of litter and trenching to prevent root inputs. Our objective was to examine seasonal dynamics of soil phosphatase and β-glucosidase activities and to determine the effects of detrital manipulations on these dynamics. We found that the litter additions did not affect enzyme activities, but removal of roots caused significant decreases in enzyme activities. We conclude that plant-induced changes to soil enzyme activities are driven primarily by readily available, labile carbon provided by root turnover and root exudation rather than by aboveground detrital inputs. However, these results could also have been affected by changes in soil chemistry with detrital input removal: after only 6 years of litter removal, soil cation content decreased and soils became more acidic, both of which could inhibit enzyme activity. The soil phosphatase and β-glucosidase enzymes measured showed similar seasonal dynamics. Both enzymes showed the highest activities in spring coincident with high soil moisture and, presumably, high root activity. The minimal response of soil enzyme activity to dramatic litter additions suggests a level of resilience in ecosystem function in this forest, and suggests that aboveground litter is not a significant source of labile carbon to microbes in the mineral soil.

Grasslands recovered by sowing low diversity seed mixtures of local prove- nance are usually managed by mowing. Besides restoration success only a few studies have focused on the direct effects of post-restoration mowing on recovered grassland vegetation. In this study we followed vegetation changes in 13 successfully recovered grasslands in 5 9 5-m-sized sites with continuous and ceased mowing at Hortobagy National Park, East- Hungary. We asked the following questions: (i) What are the effects of cessation of mowing on the vegetation structure and diversity of recovered grasslands? (ii) What are the effects of cessation of mowing on the abundance of sown grasses, target and undesirable species? (iii) Is yearly mowing an appropriate management tool for the maintenance of recovered grasslands? Our results showed that the cessation of mowing caused litter accumulation, while diversity, total vegetation cover and the cover of sown grasses decreased compared to the mown sites. The cover of undesirable perennial species was significantly higher in unmown sites than in mown ones. The species composition of mown sites remained more similar to near-natural grasslands than the unmown ones. Our results suggest that without regular post-restoration mowing the favourable status of recovered grasslands can rapidly decline due to litter accumulation and by the expansion of unde- sirable species, even in the short-run. We also stress that while yearly mowing is enough to maintain grasslands recovered by low-diversity seed sowing, it cannot be considered to be enough to recover target vegetation composition.

For an effective conservation and management in grasslands it is essential to understand mechanisms sustaining biodiversity. To gain knowledge is especially crucial in stressed grasslands harbouring a unique flora and fauna, like alkali grasslands. Aboveground vegetation, seed bank and environmental factors were studied in three stands of the following alkali grassland types: (i) Artemisia dry alkali grasslands at highest elevations; (ii) Puccinellia high and (iii) Puccinellia low grasslands at medium to low elevations, and (iv) Juncus wet alkali grasslands at the lowest elevations. We tested the following hypotheses: (i) Seed bank species diversity and density are the highest in the most stressed grassland types, where regeneration by seeds could have a major importance in sustaining vegetation diversity. (ii) Seed bank density of hygrophytes increases with decreasing elevation, because the cover of hygrophytes in the vegetation increases with decreasing elevation. The mean seed bank density ranged from 30,104 up to 51,410 seeds/m2, which is higher than in most dry grasslands. Both the lowest seed bank density and diversity were detected in the most stressed Puccinellia high grasslands; Spergularia salina was the only abundant seed bank species (possessing at least 1000 seeds/m2). These results not supported our first hypothesis. We detected the highest seed densities of almost all hygrophyte species in the lowest-elevated Juncus grasslands. But, we did not find a significant monotonous correlation between elevation and the overall hygrophyte seed bank density; because most of the hygrophyte species were missing from the seed bank at the medium-elevated, but most saline Puccinellia grasslands. Thus, our results only partly supported the second hypothesis. In total we detected more species in the seed bank than in the aboveground vegetation which emphasises that seed bank plays an important role in sustaining the diversity of alkali grasslands. However, characteristic graminoids possessed no considerable seed bank, except for Juncus compressus (up to 38,619 seeds/m2). We can conclude that persistence and establishment of most alkali grassland species are not supported by the local persistent seed bank.

Question Based on the spontaneous vegetation development of old-fields in the Nyirseg and Kiskunsag sand regions (Hungary), we aimed to answer the following questions using the chronosequence method: (1) how do the proportions of different functional groups change during succession; (2) which target species establish successfully in the old-fields during the course of succession; and (3) how successful is spontaneous succession in the recovery of target grasslands? Location Two sand regions of the Great Hungarian Plain: (1) the Nyirseg sand region (East Hungary, acidic sand, moderately continental climate) and the Kiskunsag (Central Hungary, calcareous sand, continental climate). Methods Altogether 24 old-fields were classified into young (

Previous studies on phytoremediation reported contradictory or inconsistent results on the Cd, Pb, and Zn accumulation in and among plant parts of willow (Salix) species. We hypothesized that metals could accumulate in all plant organs in different concentrations and the metal accumulation in tissues would be increased with exposure time. Furthermore, we analysed the effect of soil pH on metal accumulation, and the correlation between metals. We evaluated published information on Cd, Pb, and Zn accumulation in root, stem, twig, and leaf of willow species using meta-analysis. Results showed that all parts of willow species accumulated significantly more Cd, Pb, and Zn in contaminated soils than in uncontaminated soils. However, the metal accumulation was significantly different among plant parts. We concluded that willow species were proven to be prosperous accumulators of Cd (twigs and leaves), Pb (roots and twigs) and Zn (twigs). We found that Cd accumulation rate in stems is higher in soils with lower pH. Significant positive correlation was found between the accumulations of Cd and Zn in stems. Accumulation rates of Cd (both in leaves and twigs) and Zn (in twigs) were increased significantly with exposure time and the accumulation was successful for at least 3 years.

Pesticide residues were determined in about 120 soil cores taken randomly from the top 15 cm layer of two sunflower fields about 30 days after preemergence herbicide treatments. Samples were extracted with acetone-ethyl acetate mixture and the residues were determined with GC-TSD. Residues of dimethenamid, pendimethalin, and prometryn ranged from 0.005 to 2.97 mg/kg. Their relative standard deviations (CV) were between 0.66 and 1.13. The relative frequency distributions of residues in soil cores were very similar to those observed in root and tuber vegetables grown in pesticide treated soils. Based on all available information, a typical CV of 1.00 was estimated for pesticide residues in primary soil samples (soil cores). The corresponding expectable relative uncertainty of sampling is 20% when composite samples of size 25 are taken. To obtain a reliable estimate of the average residues in the top 15 cm layer of soil of a field up to 8 independent replicate random samples should be taken. To obtain better estimate of the actual residue level of the sampled filed would be marginal if larger number of samples were taken.

The role of fragment size, isolation and habitat diversity in the conservation of spider assemblages living in fragmented landscape were studied in dry sandy grasslands (East Hungary, Nyirseg). Spiders were collected using pitfall traps at eight dry grassland fragments from 2001 to 2009 from March to October fortnightly. We tested the rules of island biogeography, which suggest that the species richness increases with the size and decreases with the isolation of fragments. The habitat diversity is an important factor for species richness, since large areas usually have more habitats; therefore, the number of species may be higher in these areas. During the 9-year study period, altogether 10,544 individuals belonging to 106 species were collected. Contradicting the classical theory, we found a significant negative relationship between the total number of spider species and the grassland size, while the ratio of sandy grassland specialist spider species increased with fragment size. The relationship between the ratio of generalist species and the fragment size was not significant. The overall species richness and the isolation of studied grasslands did not show a significant relationship. The ratio of sandy grassland specialist species decreased, while the ratio of generalist species increased with the increasing of isolation. The habitat diversity did not show any effect on spider species richness. We concluded that to conserve the habitat specialist species it is recommended to preserve the large and least isolated grassland fragments, furthermore to increase the size of small fragments with the restoration of the adjacent croplands.

The required quality of compost depends on its final use. All the requirements must be focused on obtaining a product with an acceptable aspect and smell, which is hygienic and free from (or with only traces of) impurities and contaminants. The concept of compost quality especially relevant when the compost is used directly, as a substrate for seedling production or in pots; these applications need high-quality compost. The quality of compost based on concentrations of heavy metals and organic pollutants and on the absence of pathogens. The aim of the experiment was to prove the absence of the risk using this material in cereal production. The results of the last years suggest that there was no toxic element accumulation in the grain yield of triticale plants.Monitoring of phatogen reduction shows the conventional treatment by mesophilic digestion gives a limited reduction in the content of phatogens. The potential toxic effect of anaerobic digestate was measured in biotest with ryegrass (Lolium perenne) ...

Stoichiometry theory states that the elemental composition of individual organisms is a taxon-dependent trait, and that organisms maintain relatively constant body nutrient composition, independent of food nutrient content or ingestion rate. Some recent studies have pointed out that assuming a strict homeostasis in fish is an over-simplification, so that nutrient ratios in fish bodies may not be as constant as previously thought. In this study, our aims were (a) to assess the overall nutrient composition of roach, (b) to reveal any significant differences in elemental composition of roach between populations from different lakes and (c) to relate these potential differences to environmental parameters and fish condition. The mean elemental composition of roach (whole fish) was 45.0 ± 5.3 % carbon (C), 10.2 ± 0.8 % nitrogen (N), and 2.4 ± 0.5 % phosphorus (P), while their molar C/N/P ratio was approximately 50:10:1. The elemental composition of roach was not as constant as homeostatic stoichiometry models would predict. Significant differences were found in the carbon, nitrogen, and phosphorus contents of fish sampled from different lakes. Productivity of lakes (expressed as chlorophyll-a) was positively correlated with %C, C/N, C/P, and N/P ratios, and negatively correlated with %N and %P. In turn, mean lake temperature was negatively correlated with %C and C/N ratio, but not with other nutrients or nutrient ratios. Condition factor was negatively related to the %C of fish, but it did not correlate significantly with %N, %P, or nutrient ratios. Our results on intraspecific nutrient variation illustrate the potential differences between populations and emphasize the importance of lake-specific approaches.

Climate change is a global problem. During the last century the increase of annual average temperature was 0.68°C, while the decrease of annual average of precipitation was 83 mm in Hungary. According to the long term meteorological data of Sikfőkut forest ILTER site the annual average temperature increased while average of yearly precipitation decreased, the forest climate became warmer and dryer. These processes could considerably contribute to forest decline, not only in the Quercetum petraeae-cerris stand of Sikfőkut, but everywhere in the country. Species composition and structure of the forest have changed considerably, as 68% of sessile oak (Quercus petraea) and 16% of Turkey oak (Quercus cerris) have died. Forest decline resulted in the breaking up of the formerly closed canopy, and consequently, in the formation of gaps in the forest. In the gaps, a secondary canopy developed with tree species of less forestry value. As a consequence, mass regeneration of field maple (Acer campestre) appeard in the gaps. The formation of gaps accelerated the warming and aridity of forests. In the article we answer the following question: how did climatic change and changing forest structure influence the leaf-litter production in the last four decades? oak forest / oak decline / Sikfokut Project / litter production / climate change

Freshwater biodiversity is declining faster than marine or terrestrial diversity, yet its drivers are much less known. Although dams were shown to negatively affect river habitats, fragmentation by bridges has received less attention and is not as well understood. We tested whether and how bridges present barriers to aquatic insects by studying mass swarmings of Palingenia longicauda mayflies on river Tisza (NE-Hungary). Behavioural observations showed that upon approaching the bridge, upstream-flying mayflies typically turned back and 86% of them never crossed the bridge. Lack of physical contact showed that the bridge was an optical, rather than a mechanical barrier for the polarotactic mayflies. Imaging polarimetry showed that the bridge disrupted the horizontally polarizing channel guiding the flight of mayflies above the river. Energy loss, demonstrated by calorimetry, and time constraints forced females to lay eggs only downstream from the bridge. Counts of larval skins shed by swarming individuals showed nearly 2 to 1 female per male downstream from the bridge, while sex ratio above the bridge was slightly male-biased. We suggest that the surplus of parthenogenetic females, that produce only female larvae, downstream from the bridge may have led to the observed sex-ratio bias since the construction of the bridge (1942). Our results demonstrate that bridges can be optical barriers for aquatic insects and can cause population-level impacts, such as biased sex ratios, in natural populations. Sex ratio biases due to bridges may decrease effective population size and genetic variability, which may have contributed to the recent extinction of this species from most of Europe.

A major objective of our research was to survey soil biological activity and organic mattercontent reduction in a Central European oak forest during treatments of various detritus inputs within theSíkfkút DIRT (Detritus Input and Removal Treatments) Project. Beside the control, three detritusremoval and two detritus duplication treatments were applied. Our examinations have proven that soilorganic matter content declined relatively fast in detritus removal treatments. The reduction wasespecially remarkable in root detritus removal treatments, where – due to the lack of transpiration – soilswere moister during the whole year than in the other treatments. The higher moisture content, despite ofthe reduction of detritus input, produced an intense soil respiration. This can be explained by the fact thatdecomposing organisms have increased the use of soil organic matter. Detritus input reduction had asignificantly greater effect on soil respiration and organic matter content than detritus input duplicationof the same extent. The latter did not cause any significant change compared to the control.

Ground beetles were studied among grassland — forest edge — beech forest habitats in Hungary, using pitfall traps. We hypothesised that the activity density and species richness of carabids were the highest in the forest edge, the activity density and the number of forest species were decreasing, while the activity density and the number of generalist species increasing from the forest towards the grassland. Carabid assemblage of the grassland was the most diverse and the forest was the least diverse if measured by Renyi diversity. The average species richness per trap was significantly higher in the grassland and in the edge than in the forest. The number of forest species was significantly higher in the edge than elsewhere. The number of generalist species was highest in the grassland and decreased towards the forest. The activity density of carabids was significantly higher in the forest and in the forest edge than in the grassland. The activity density of forest species was higher in the forest and in the edge than in the grassland. The activity density of the generalist species was higher in the grassland than in the forest edge and in the forest. There were seven species characteristic to the grassland as identified by IndVal; two species were characteristic to the edge, and two species were characteristic both to the forest and the edge. We found that humidity was the highest in the forest; Pterostichus oblongopunctatus and Molops piceus were associated with the forest habitat, while Abax ater and Pterostichus melanarius were associated with the forest edge according to the RDA. The the shrub cover was the most relevant factor in the edge; Abax ater and Pterostichus melanarius were associated with this habitat.

We studied the effect of sowing low-diversity seed mixtures (containing 2–3 competitive grass species) on the regeneration of vegetation on croplands previously used as alfalfa fields. In four permanent plots in 10 restored fields (four with alkali and six with loess seed mixture) the cover of flowering plants was recorded and phytomass was measured between 2006 and 2008. We asked three questions: (i) How fast will weedy, short-lived species decrease in abundance during secondary succession enhanced by sowing low-diversity seed mixtures? (ii) Can weeds be suppressed by sowing competitive native grasses, followed up by management by mowing? (iii) Can succession towards the target native grasslands be accelerated by sowing only low-diversity seed mixtures compared to set-aside old field succession? Our results showed that in just two years a vegetation dominated by perennial grasses has developed, which successfully prevented the establishment of weed species. These results suggested that sowing seeds of two or three competitive grass species is an effective tool to eliminate weed domination and to lead towards the restoration of species poor grasslands with grass domination such as alkali grasslands. However, the developed dense perennial grass cover and the accumulated litter may hamper the immigration of specialist species characteristic to reference grasslands. Therefore, the restoration of species-rich grasslands requires the facilitation of the immigration of grassland specialist species by further management (grazing, mowing and/or hay-transport).

We studied the potential role of seed bank in the dynamics of the understorey in a turkey oak-sessile oak forest (Querceteum petraeae-cerris) in Hungary. We used long-term records of the herb layer (1973-2006) and the seed bank composition of 2006 to assess the role of seed bank in the regeneration of herb layer. The total cover of herb layer decreased from 22% (1973) to 6% (1988), and remained low (10%) till 2006; coinciding with the increasing cover of secondary canopy dominated by Acer campestre. We found a low density seed bank (ca. 1300 seeds/m2). Altogether 33 species were germinated from the soil samples. A few generalist weed species composed the majority of seed bank. It was possible to assign a seed bank type for 19 species; 14 species out of 19 was long-term persistent. We found that the characteristic perennial forest herbs and grasses had only sparse seed bank. The Jaccard similarity between vegetation and seed bank was low (30%). Our results suggest that the continuous establishment of forest herbs are not based on local persistent seed bank; it should be based on vegetative spreading and/or seed rain.

Numerous oxbows of different sizes, depths and ages accompany alluvial rivers in the Carpathian basin. These water bodies provide various habitats for macroscopic and microscopic assemblages. Phytoplankton of 13 oxbows in the Tisza valley was studied between 2005 and 2008. In this article, we focussed on the following questions (i) do the oxbows have unique microflora? (ii) does the macrophyte coverage have a large effect on the composition and biomass of the algal assemblages? and (iii) does the higher plants dominated state result in clear-water conditions in the oxbows? The studied oxbows were in different stages of the ageing process. We classified the sampled oxbows according to their macrophyte vegetation into five types. A total of 646 species of algae were recorded in the oxbows over the study period. The microflora was dominated by cyanophytes, chlorococcalean green algae, euglenophytes and diatom species. Phytoplankton species were allocated into 32 coda. For the determination of typical algal assemblages, we used Kohonen’s Self Organizing Map (SOM) statistical analysis combined with K-means clustering, which has resulted five different types of phytoplankton associations. These types were dominated by coda Y, LO, W1, WS and J. Chlorophyll a data of the sparsely and densely vegetated oxbows did not differ, since a wide range of values characterised both types of the lakes. In this study, the composition of the microflora is similar to that of other eutrophic lakes, but some rarely occurring taxa such as Peridinium gatunense Nygaard and Peridiniopsis elpatiewskyi (Ostenf.) Bourelly might play a key role in the phytoplankton succession of the oxbows. The effect of the macrophyte coverage was decisive in the composition of the algal assemblages, and our investigations indicated that, in the case of the oxbows, the macrophyte-dominated state does not necessarily result in a clear-water state.

We tested wetland-restoration management techniques to restore and increase the diversity of aquatic beetle assemblages. Three wetland treatments were examined that included: (i) unplanted surface flow (unplanted SF) wetland, (ii) surface flow (planted SF) wetlands planted with aquatic plants, and (iii) subsurface flow (SSF) wetlands. Species richness of aquatic beetles in SF wetlands was highest in spring, while the abundance was lower in the planted SF wetlands than in the unplanted SF wetland. Planted SF wetlands had a slightly higher diversity of beetles than that of the unplanted SF wetland. The planted and unplanted SF wetlands had similar attributes throughout the rest of the year. In SSF wetlands, beetles were significantly more abundant and species rich in spring than either in the planted or in the unplanted SF wetlands. Beetle diversity in SSF wetlands was higher than that in SF wetlands. During the summer, the differences between treatments disappeared. Our results suggested that: (i) vegetation planting was a successful wetland restoration technique, due to the increased habitat diversity, (ii) subsurface flooding provided fishless temporary waters with favorable breeding conditions for aquatic beetles, thus it was also a useful restoration technique, and (iii) significant seasonal differences in abundance and species richness reflected the characteristic breeding habits of aquatic beetles.

Maintaining connectivity among local populations in a fragmented landscape is crucial for the survival of many species. For isolated habitat patches, stochastic fluctuations and reduced gene flow can lead to high risk of extinction. The connectivity of the landscape is especially crucial for the carabid species living in the fragmented forests of the Bereg plain (NE Hungary and W Ukraine) because a highway will be constructed through the plain. Our purpose is to (1) evaluate the impacts of three possible highway tracks, (2) suggest a solution that is realistic with less impact on connectivity than other plans and (3) discuss how to decrease the disadvantageous effects of each track. Our results, based on a network analysis of landscape graph of patches and ecological corridors, indicate that the intended highway could have deleterious consequences on forest-living carabids. Relatively simple actions, like the establishment of stepping stones, could compensate for the loss of habitat connectivity and promote the survival of carabids, or minor modifications in one possible track could diminish its adverse effects. While many other studies would be needed for a comprehensive assessment of the biotic impact of the highway, we provide an example on the usefulness of network analysis for land use management.