Egyes környezeti terhelések (kadmium, króm, nikkel, ólom) hatásának vizsgálata baromfi embrió modellben különös tekintettel a lipidperoxidációra és a glutation redox rendszer működésére = Investigation of some environmental loading (cadmium, chromium, nickel, lead) in chicken embryo model system with special attention to the peroxidation and the glutathione redox system

A fémterheléseket az inkubáció előtt alkalmazott egyszeri fürösztéssel, illetve a légkamrába történő injek-tálásos technikával idéztük elő kadmium, króm és nikkel vízoldható sóinak szubletális dózisaival. Megállapítottuk, hogy a fürösztéses módszerrel végzett fémterhelés nem idézett elő szignifikáns morfológiai elváltozásokat a csirke embrióban. A kezelések hatására az MDA tartalom nőtt, a GSHPx aktivitás pedig csök-kent, ami oxidatív stressz folyamatokra utal. Az injektálással végzett kezelések hatására nem szignifikánsan nőtt az elhalt embriók és a morfológiai elváltozások aránya. Nikkel hatására a GSH koncentráció szignifikán-san kisebb, a GSHPx aktivitás pedig nagyobb volt a kontroll-hoz viszonyítva. A változások fokozott lipid per-oxidációra utalnak, amelyet az antioxidáns rendszer ha-tékonyan kivédett. Kadmium hatására a MDA kon-centráció és a GSHPx aktivitás szignifikánsan nőtt, amely fokozott lipidperoxidáció mellett az antioxidáns védelmi rendszer fokozott aktivitására utal. A króm hatására az MDA tartalom nőtt, a GSHPx aktivitás pedig csökkent, ami a glutation redox rendszer terhelését jelzi. Az injektálásos módszerrel kezelt csirkékkel vég-zett nevelési kísérletben a króm és a nikkel terhelt csoportokban a kis állatlétszám miatt csak előzetes ered-ményeket kaptunk, amelyek még a kelést követően is jelentős oxidatív stresszre és a glutation rendszer ki-merülésére mutatnak. A kadmium terhelés a nevelési kísérlet során nem mutatott számottevő változásokat. | Metal-load was carried out using single bathing or single injection into air cell before incubation with sub-le-thal doses of water-soluble salts of cadmium, chromium and nickel. It was found that metal-load with bath-ing method did not cause significant morphological changes in the chicken embryo. The treat-ments caused increase of MDA content and decrease of GSHPx activity as which suggest oxidative stress processes. As effect of the treatments with single injection ratio of the dead embryos and morphological abnormalities increased not significantly. Nickel caused decrease in the GSH content and increase in GSHPx activity, which suggests improvement in lipid peroxidation which was defence by the antioxidant system effectively. Cadmium caused significant increase in both MDA content and GSHPx activity which suggest improvement in lipid peroxidation and higher activity of the antioxidant defence. Chromium caused higher MDA content and lower GSHPx activity, which suggests the exhaustion of the glutathione redox system. In the rearing experi-ment with chicken hatched from the eggs treated with injection method in the case of chromium and nickel loading only preliminary results were obtained because of the low number of viable animals. The results suggests oxidative stress and exhaustion of the glutathione system even after hatching. Cadmium did not cause measurable effects during the rearing period

Synergistic effects of the components of global change: Increased vegetation dynamics in open, forest-steppe grasslands driven by wildfires and year-to-year precipitation differences

Climate change and land use change are two major elements of human-induced global environmental change. In temperate grasslands and woodlands, increasing frequency of extreme weather events like droughts and increasing severity of wildfires has altered the structure and dynamics of vegetation. In this paper, we studied the impact of wildfires and the year-to-year differences in precipitation on species composition changes in semi-arid grasslands of a forest-steppe complex ecosystem which has been partially disturbed by wildfires. Particularly, we investigated both how long-term compositional dissimilarity changes and species richness are affected by year-to-year precipitation differences on burnt and unburnt areas. Study sites were located in central Hungary, in protected areas characterized by partially-burnt, juniper-poplar forest-steppe complexes of high biodiversity. Data were used from two long-term monitoring sites in the Kiskunság National Park, both characterized by the same habitat complex. We investigated the variation in species composition as a function of time using distance decay methodology. In each sampling area, compositional dissimilarity increased with the time elapsed between the sampling events, and species richness differences increased with increasing precipitation differences between consecutive years. We found that both the long-term compositional dissimilarity, and the year-to-year changes in species richness were higher in the burnt areas than in the unburnt ones. The long-term compositional dissimilarities were mostly caused by perennial species, while the year-to-year changes of species richness were driven by annual and biennial species. As the effect of the year-to-year variation in precipitation was more pronounced in the burnt areas, we conclude that canopy removal by wildfires and extreme inter-annual variability of precipitation, two components of global environmental change, act in a synergistic way. They enhance the effect of one another, resulting in greater long-term and year-to-year changes in the composition of grasslands

Ecological dynamics: the spread of invasive plant species in Hungary's ecosystem types between 2009-2018

Our research focuses on analyzing the spatiotemporal dynamics of five invasive plant species (Ailanthus altissima, Asclepias syriaca, Elaeagnus angustifolia, Robinia pseudoacacia, and Solidago spp.) in various ecosystem types in Hungary from 2009 to 2018. Using the National Geospatial Database of Invasive Plants (NGDIP) and the Ecosystem Map of Hungary (EMH), we examine how these species' distribution and occurrence changed over time. Our methodology and findings offer valuable insights for invasive species research. Our results indicate that Asclepias syriaca and Robinia pseudoacacia increasingly threaten grasslands and complex cultivated areas. Ailanthus altissima and Asclepias syriaca are declining in urban settings due to harsher environmental conditions, while Solidago spp. are expanding in wetlands, impacting riparian biodiversity.

Long-term weather sensitivity of open sand grasslands of the Kiskunság Sand Ridge forest-steppe mosaic after wildfires

We studied the long-term impact of wildfire on the vegetation dynamics of sand grasslands in a forest-steppe vegetation mosaic in Central Hungary (Kiskunság). Longterm permanent quadrat monitoring was carried out from 1997 to 2008. We sampled the forest-steppe mosaic both in burnt and unburnt areas in 100 patches altogether using one by one meter quadrats. The effect of fire and precipitation on vegetation dynamics was characterized by patch type transitions between years. Patch types were defined by means of Cocktail method. Nine patch types of sand grasslands were altogether identified. The least productive patch types, bare soil and cryptogam dominance, did not occur in the burnt patches, while annual dominated patch type appeared only in burnt patches. The frequencies of patch type changes were significantly higher in burnt patches than in unburnt ones, independently on the time since fire. All the eight patch types found in the unburnt patches proved permanent, while in the burnt patches only four of seven were so. The relative frequency of patch type changes did not correlate to the precipitation in the vegetation period in the unburnt patches, while positively correlated in the burnt patches. It was concluded that the long-term difference in grassland dynamics between the unburnt and burnt patches, i.e. the excess of the patch type transitions in the burnt grasslands, are due to increased drought sensitivity of the grassland, which is the consequence of the elimination of the woody component of the forest-steppe vegetation