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 factors threatening the biodiversity of kurgans are intensified agriculture and construction works. We conclude that kurgans can play a crucial role in preserving steppe vegetation, especially in intensively used agricultural landscapes in the western part of the steppe zone. Despite the vital role of kurgans in sustaining steppe vegetation, we identified serious knowledge gaps on their distribution, vegetation, flora and fauna and their potential role in steppe restoration.
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.
Kurgans (ancient burial mounds) constitute small steppe habitat islands within the “sea of fields” forming the landscape of southern Ukraine. We found that they can function nearly as "oceanic islands," particularly for steppe vascular plant species as their richness is strongly controlled and positively related with kurgan size, landscape‐scale connectivity and local‐scale habitat heterogeneity indices.
Civilizations, including ancient ones, have shaped global ecosystems in many ways through coevolution of landscapes and humans. However, the cultural legacies of ancient and lost civilizations are ...rarely considered in the conservation of the Eurasian steppe biome. We used a data set containing more than 1000 records on localities, land cover, protection status, and cultural values related to ancient steppic burial mounds (kurgans); we evaluated how these iconic and widespread landmarks can contribute to grassland conservation in the Eurasian steppes, which is one of the most endangered biomes on Earth. Using Bayesian logistic generalized regressions and proportional odds logistic regressions, we examined the potential of mounds to preserve grasslands in landscapes with different levels of land‐use transformation. We also compared the conservation potential of mounds inside and outside protected areas and assessed whether local cultural values support the maintenance of grasslands on them. Kurgans were of great importance in preserving grasslands in transformed landscapes outside protected areas, where they sometimes acted as habitat islands that contributed to habitat conservation and improved habitat connectivity. In addition to steep slopes hindering ploughing, when mounds had cultural value for local communities, the probability of grassland occurrence on kurgans almost doubled. Because the estimated number of steppic mounds is about 600,000 and similar historical features exist on all continents, our results may be applicable at a global level. Our results also suggested that an integrative socioecological approach in conservation might support the positive synergistic effects of conservation, landscape, and cultural values.
Contribución de los valores culturales para la conservación esteparia en los antiguos montículos funerarios de Eurasia
Resumen
Las civilizaciones modernas y antiguas han moldeado de muchas maneras los ecosistemas globales mediante la coevolución del paisaje y la humanidad. Sin embargo, pocas veces se considera el legado cultural de las civilizaciones perdidas o antiguas para la conservación del bioma de la estepa euroasiática. Usamos un conjunto de datos que contiene más de 1,000 registros de las localidades, cobertura del suelo, estado de protección y valores culturales relacionados con los antiguos montículos funerarios de esta estepa (kurgans). Después analizamos cómo estos símbolos icónicos y distribuidos extensamente pueden contribuir a la conservación de los pastizales en la estepa euroasiática, uno de los biomas en mayor peligro de extinción. Analizamos el potencial de conservación de los montículos en paisajes con diferentes niveles de transformación en el uso de suelo mediante regresiones logísticas generalizadas bayesianas y regresiones logísticas de probabilidades proporcionales. También comparamos el potencial de conservación de los montículos dentro y fuera de las áreas protegidas y evaluamos si los valores culturales locales conservan los pastizales dentro de estas mismas áreas. Los kurgans fueron de gran importancia para la conservación de los pastizales en los paisajes transformados ubicados fuera de las áreas protegidas, en donde llegaron a fungir como hábitats aislados que contribuyeron a la conservación y conectividad del hábitat. Además de que las pendientes pronunciadas impiden el arado, cuando los montículos contaban con valor cultural para las comunidades locales, la probabilidad de que el pastizal se ubicara sobre un kurgan casi se duplicó. Ya que se estima que el número de montículos esteparios ronda los 6,000 y que rasgos históricos similares existen en todos los continentes, nuestros resultados pueden aplicarse a nivel global. Nuestros resultados también sugieren que una estrategia socio‐ecológica integradora para la conservación podría respaldar los efectos sinérgicos positivos de la conservación, el paisaje y los valores culturales.
The fragmentation and isolation of preserved habitat patches within intensive agricultural landscape threaten species survival in steppes. In Ukraine, <5 % of the original steppe area has survived, ...mostly in nature reserves, loess ravines and kurgans (burial mounds). The latter are small, but relatively numerous objects. The aim of this study was to investigate whether plant species density (= the number of species per plot) within small steppe patches on kurgans differs from that within large steppe enclaves in southern Ukraine. Another aim was to determine the influence of patch area, isolation and heat load index on species density on kurgans. Presence-absence data for vascular plant species were collected on plots of a size of 100 and 1 m
2
. Thirty kurgans and ten sites within large steppe enclaves were sampled. Every noted species was classified as specialist or generalist. For kurgans data on area and degree of isolation were collected. Additionally the heat load index for plots on kurgans was calculated. The density of habitat specialists was higher in larger steppe enclaves than on kurgans at both spatial scales. On kurgans the most important predictors of specialist density were isolation (negative) and kurgan area (positive). The density of generalists was positively affected by the heat load index. Kurgans can provide refuges for steppe plant species. However, our results show that over a longer time period, proximity to larger steppe refuges is important to maintain species diversity within these small patches.
The habitat loss and fragmentation due to agricultural land-conversion affected the steppe throughout its range. In Ukraine, 95% of steppe was destroyed in the last two centuries. Remaining ...populations are confined to few refuges, like nature reserves, loess ravines, and kurgans (small burial mounds), the latter being often subject to destruction by archeological excavations.
Stipa capillata L. is a typical grass species of Eurasian steppes and extrazonal dry grasslands, that was previously used as a model species in studies on steppe ecology. The aim of our research was to assess genetic diversity of S. capillata populations within different types of steppe refuges (loess ravines, biosphere reserve, kurgan) and to evaluate the value of the latter group for the preservation of genetic diversity in the study species.
We assessed genetic diversity of 266 individuals from 15 populations (nine from kurgans, three from loess ravines and three from Askania-Nova Biosphere Reserve) with eight Universal Rice Primers (URPs).
Studied populations showed high intra-population variability (I: 0.262–0.419, PPB: 52.08–82.64%). Populations from kurgans showed higher genetic differentiation (ΦST = 0.247) than those from loess ravines (ΦST = 0.120) and the biosphere reserve (ΦST = 0.142). Although the diversity metrics were to a small extent lower for populations from kurgans than from larger refugia we conclude that all studied populations of the species still preserve high genetic variability and are valuable for protection. To what extent this pattern holds true under continuous fragmentation in the future must be carefully monitored.
•Kurgans are small steppe vegetation islands within arable landscape of Ukraine.•Kurgans may function for Stipa capillata as a set of dispersed refugia.•Kurgans are important for sustaining the genetic variability of S. capillata.•Genetic variation is differently partitioned on kurgans than in large refugia.•Preservation of steppe vegetation on kurgans must accompany archeological research.
Allium paniculatum L. is commonly recorded from the Euro‐Mediterranean and Irano‐Turanian regions. Evidence from literature and herbarium collections revealed that many different taxa of A. sect. ...Codonoprasum Rchb., all characterized by big size, diffuse and densely flowered umbrella, very long spathe valves, long pedicels, and cylindrical‐campanulate perigon, have been wrongly attributed to this species thus affecting records on its geographic distribution and morphological characterization. In order to define the true identity of A. paniculatum, we analyzed specimens coming from the type locality (Don River), and provided details on morphology, ecology, karyology, leaf anatomy, seed morphology and seed coat micro‐sculpturing. Taxonomic and phylogenetic relationships with related species of sect. Codonoprasum and with other taxa of different sections were investigated by means of morphological characters and molecular data from the internal transcribed spacers (ITS) nrDNA and the trnH‐psbA cpDNA region. Maximum parsimony and Bayesian inference analyses of molecular data recovered two main clades in A. sect. Codonoprasum and clearly separated A. paniculatum from related taxa. The taxonomic implications of these patterns of relationships are discussed. To our knowledge, this is the first study documenting in‐depth phylogenetic relationships within A. sect. Codonoprasum.
Habitat fragmentation can prevent gene flow between plant populations and lead to a loss of genetic diversity. However, such impact of fragmentation has not always been consistently confirmed by ...previous studies and the issue still needs further research. Particularly little is known about the impact of fragmentation on steppe plants. Steppe once covered vast, continuous areas, and nowadays is among the most fragmented biomes. In Ukraine, remnants of this habitat survived in large but few nature reserves and loess ravines as well as on kurgans (burial mounds of ancient nomadic people), which, despite their small size, are still numerous and scattered throughout the landscape.
We studied the impact of fragmentation on the genetic diversity and structure of Iris pumila, a typical species of European steppes. Our main focus was to compare the genetic characteristics between kurgan populations (n=8), and populations from larger refugia (n=6). We assessed the genetic diversity of the studied populations with Universal Rice Primers.
Our analyses revealed high genetic diversity across all investigated populations (mean He: 0.233; mean PPB: 58.57). However in kurgan populations genetic diversity was significantly higher than in larger refugia. Genetic diversity (He) was negatively correlated with population size. Most of the molecular variance (82%) was represented within populations, whereas genetic differentiation among populations was moderate (ΦST=0.160), and low among refugia types (ΦRT=0.026).
The maintenance of high genetic diversity despite two centuries of fragmentation may be related to the moderate disturbance occurring on kurgans, which enhances the sexual reproduction of the species. Moreover, we assume that species traits such as longevity and polyploidy might counterbalance genetic drift, while its self-incompatibility and presence of a soil seed bank allows for the replenishment of the gene pool. Overall, our results suggest that kurgans can protect genetic diversity of steppe species.
Results of the studies on the floristic biodiversity of the kurgans in the Pontic desert steppe of the Black Sea Lowland (Kherson Region) are presented. Twenty-six of about 130 kurgans higher than 3 ...m, distributed over an area of approx. 1500 km2, were surveyed and the flora of 5 microhabitats within every kurgan (top, southern and northern slope, southern and northern foot) was examined. The richness of the kurgan flora is estimated at 305 species. Species of alien origin constituted 23% of the total flora, which indicates limited anthropogenic influence. Species of two classes, Festuco-Brometea and Stellarietea mediae were predominant, which also confirmed the semi-natural character of the kurgan flora. The lowest number of species was recorded on top, which was relatively rich in synanthropes, particularly therophytes (Stellarietea mediae). The north side was richer in species than the south side of the kurgans. Steppe species were the most stable and important component of the flora of the slopes (45-47% of the species represented the class Festuco-Brometea). The total flora of the foot contained more species and was more diversified than the flora of the slopes (although the mean number of species was similar in both habitats), but each species occurred at low frequency. There was a higher proportion of species which were introduced from the area surrounding the kurgans, e.g. weeds, halophytes, meadow species, as well as trees which are rarely found in the desert steppe zone. In spite of the small size of the kurgans, significant differences between the floristic composition of the various microhabitats were detected.
Based on the analysis of more than 17,000 vegetation plots (relevés), the participation of 261 protected species (254 vascular plants, six lichens, and one bryophyte) in 30 EUNIS grassland habitat ...types was revealed. Vegetation plots were assigned to the habitat types using the EUNIS-ESy expert system with further verification. We consider as protected species those listed in the current edition of the Red Data Book of Ukraine, Resolution 6 of the Bern Convention, Annexes II and IV of the Habitat Directive, and the IUCN Red List (only categories VU, EN, CR). The participation of protected species was studied according to the following three criteria: (1) the total number of protected species in the plots assigned to a certain habitat type, (2) the number of plots in which at least one protected species is present, and (3) the mean number of protected species per plots within each habitat type. True steppes (R1B) and meadow steppes (R1A) differed with a significant predominance of the total number of protected species. Arctic alpine calcareous grassland (R44) and Continental dry rocky steppic grassland and dwarf scrub on chalk outcrops (R15) had the largest proportion of plots with protected species and the highest mean numbers of protected species per relevé. Saline habitats, in particular Temperate inland salt marsh (R63) and Semi desert salt pan (R64), were characterized by the smallest number of plots with protected species. Among all species, Gymnadenia conopsea, Stipa capillata, Colchicum autumnale and Gladiolus imbricatus occurred in the largest number of studied habitat types. Based on the results of the analysis, appropriate ways of optimizing the protection of grassland habitats and protected species are proposed.
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