Steppe is among the most endangered biomes of the world, especially in Eastern Europe, where more than 90 % of original steppes have been destroyed due to conversion into croplands, afforestation and other human activities. Currently, steppe vegetation is often restricted to places unsuitable for ploughing, such as ancient burial mounds called kurgans. The aim of our study was to collect and synthesise existing knowledge on kurgans by a review of research papers and grey literature. The proportion of kurgans covered by steppe vegetation increases from west to east and from lowlands to uplands. Despite their small size, kurgans act as biodiversity hotspots and harbour many red-listed species. High overall species richness and a high proportion of grassland specialists are maintained by a pronounced fine-scale environmental heterogeneity. The main Communicated by Jürgen Dengler.

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Polycyclic aromatic hydrocarbons and heavy metal (Pb, Cd, Cu, Zn, Hg, Fe, Co, Cr, Mo) contents were established in soil and plant samples collected in different areas of the railway junction Iława Główna, Poland. Soil and plant samples were collected in four functional parts of the junction, i.e. the loading ramp, main track within platform area, rolling stock cleaning bay and the railway siding. It was found that all the investigated areas were strongly contaminated with polycyclic aromatic hydrocarbons (PAHs). The PAH contamination of the soil was the highest in the railway siding and in the platform area (59,508 and 49,670 μg kg−1, respectively). In the loading ramp and cleaning bay, the PAH concentration in soil was lower but still relatively very high (17,948 and 15,376 μg kg−1, respectively). The contamination in the railway siding exceeded the average control level up to about 80 times. In the soil of all the investigated areas, four- and five-ring PAHs prevailed. The concentrations of PAHs were determined in four dominating species of plants found at the junction. The highest concentration was found in the aerial parts of Taraxacum officinale (22,492 μg kg−1) growing in the cleaning bay. The comparison of the soil contamination with PAHs in the investigated railway junction showed a very significant increase of the PAHs level since 1995. It was found that the heavy metal contamination was also very high. Pb, Zn, Hg and Cd were established at the highest levels in the railway siding area, whereas Fe concentration was the highest in the platform area. A significant increase in mercury content was observed in the cleaning bay area. The investigations proved very significant increase of contamination with PAHs and similar heavy metals contamination in comparison with the concentration determined in the same areas 13 years ago.

Questions: Steppes are among the most transformed and fragmented biomes in the world, but studies on the impact of habitat loss and fragmentation on these zonal grasslands are scarce. In many regions, steppe has survived only on small habitat islands, particularly on kurgans (ancient burial mounds) surrounded by intensive croplands. We asked how the size of kurgans, their isolation and other landscape and local factors influence their species richness. Location: Southern Ukraine. Methods: We recorded all species of vascular plants and assessed local (area, steepness, disturbance level), landscape (distance to the nearest habitat patch, habitat amount in the surroundings, surrounding type, distance to settlements) and climatic (precipitation) conditions of 112 kurgans. We analysed species-area relationships (SARs) for total richness, habitat specialists and generalists. Then, we assessed importance of environmental factors in explaining the residuals of the SAR models. Results: Patch area explained more than 50% of variance in total and specialist species richness. The slopes of the power function SAR (z-values) were higher for specialists than for generalists. Connectivity measures (the distance to the nearest large habitat enclave and share of habitat in the surroundings) were more important for richness of specialists than for that of generalists, which were more controlled by the kurgan's surroundings. Conclusions: We found that for specialist species the steppe "islands" follow the theory of island biogeography closely, but less so for generalist species. Combined with the revealed importance of connectivity for specialist species richness, we conclude that the conservation value of the kurgans in the long term likely can only be achieved with larger steppe areas in the surroundings.

Apart from roads, railways are one of the principal means of transportation. The specificity of rail transportation causes some environmental problems. The study presents a review of the major environmental problems connected with railway transportation. The construction of railway tracks and properties of used materials, as well as the maintenance of railway infrastructure are responsible for the specific habitat condition with alkaline soil reaction and varying but rather high levels of nutrients, which favour plant encroachment and growth. The results of investigations described in this study show clearly that railway transportation causes typical organic and inorganic contamination. Among the most important railway pollutants are polycyclic aromatic hydrocarbons, heavy metals, and to some extent, polychlorinated biphenyls. The study also presents some information about the progress of floristic studies in operating and abandoned railway lines. In addition some trends in the transformation of the flora in abandoned railway areas are discussed: the retreat of alien species with a short life cycle, the encroachment of native perennial plants and an increase in the number of trees.

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Abstract-Flora similarity was assessed using com plete floristic lists of five ecotopes in each of four m ounds along the transect from m eadow steppes to desert steppes. It was found that the circum apical similitude of floras is m ore significant than the expositional similitude. Soil analysis in separate ecotopes showed th at reg ular changes in the biogeochem ical features are manifested along the topographic gradient and under the effect of the insolation exposure of slopes in local (m ound) ecosystems. It was noted th at the slopes are char acterized by the m ost abundant steppe vegetation classes in the phytosociological spectrum of m ound ecotopes.

Abstract. Floristic studies were carried out in NE Poland in [2007][2008] in three types of railway areas: operating tracks, tracks abandoned less than 10 years ago, and tracks abandoned more than 10 years ago. In the 41 sections of railway tracks surveyed, 338 species were recorded, including 22 species that occurred at > 50% frequency, 27 species strongly associated with operating railway areas, and 4 species typical of railway areas in Poland. Comparative analysis of the flora of the 3 types of railway areas investigated showed significant differences in the richness and structure of their floras.