PETROPHYTIC VEGETATION OF THE DONETS RIDGE

Unique plant habitats are described for the petrophytic communities of the Donets ridge. A scientific basis for the conservation of zonal steppe vegetation and its petrophytic variants is proposed using a number of the characteristic petrophytic communities of Donets ridge as examples. Several criteria of conservation importance are proposed to evaluate the reasons for including the natural territories in the list of protected objects. Recommendations for improving the protection of the steppe petrophyte vegetation of the Donetsk ridge are given. Proposals for creating an ecological network within the studied area have been formulated.

Long term changes of the inner-alpine steppe vegetation: the dry grassland communities of the Vinschgau (South Tyrol, Italy) 40–50 years after the first vegetation mapping

Aims: The Vinschgau is the driest inner-alpine valley in the Eastern Alps and harbours a unique steppe vegetation. We studied these dry grassland communities and aimed to answer the following questions: Which plant communities can be found currently? Do the syntaxa described by Braun-Blanquet in the 1960s still prevail in the area? Has there been any change in species composition over the last 40–50 years? Study area: Along an approximately 40 km transect, the south-facing slopes of the Vinschgau valley (South Tyrol, Italy) from Mals to Plaus were investigated. Methods: For the classification, 92 relevés were sampled in 2019 and compared with 76 relevés from the 1960s and ´70s by means of vegetation tables and ordinations (Detrended Correspondence Analysis). Results: Based on our investigation, the majority of dry grassland communities can be classified as Festuco-Caricetum supinae. Three subassociations were defined by the dominant species Stipa capillata, Bothriochloa ischaemum and Stipa pennataagg. The comparison of new and old relevés shows an increase in species from the class Sedo-Scleranthetea (e.g. Trifolium arvense, Erodium cicutarium) and the association Artemisieto-Agropyretum. In addition, ruderal elements (e.g. Erigeron annuus, Convolvulus arvensis) have also migrated into dry grasslands. A shift in the dominance over time can be recognized as well. In particular, Festuca rupicola and to some extent also Stipa capillata, have increased in abundance and frequency. Conclusions: We suggest to include the investigated closed dry grasslands in the alliance Festucion valesiacae. The rank of the character species at association, alliance and order level should be re-analysed. In order to obtain a better syntaxonomic overview of western and eastern alpine dry grassland communities in relation to Eastern European dry grasslands, a comprehensive study is absolutely necessary. Furthermore, long-term vegetation dynamics and vegetation change need to be studied in more detailed future studies. Taxonomic reference: Fischer et al. (2008). Syntaxonomic references: Mucina et al. (2016) for syntaxa from alliance to class level; Braun-Blanquet (1961) for associations. Abbreviations: agg. = aggregate; cf. = confer (means ‘compare’); DCA = Detrended Correspondence Analysis; s. lat. = sensu lato; s. str. = sensu stricto

New higher syntaxa of the steppe vegetation in the North Caucasus

Geobotanical studies were carried out in the North Caucasus, in the Stavropol kray (Russia) on Beshtau, Byk, Verblyud, Dzhutsa, Dubrovka, Zolotoy Kurgan, Kokurtly, Lysaya, Mashuk, Yutsa magmatic mountains, Bor-gustan and Dzhinal ringes in 2017, 2019–2021. Syntaxonomic analysis carried out from the standpoint of J. Braun-Blanquet approach (1964) made it possible to establish 2 new associations (Allio albidi–Dictamnetum caucasici ass. nov. hoc loco, Helianthemo buschii–Elytrigietum stipifoliae ass. nov. hoc loco), 2 new alliances (Allio albidi–Dictamnion caucasici all. nov. hoc loco, Helianthemo buschii–Elytrigion stipifoliae all. nov.hoc loco) and 1 new order Galio biebersteinii–Bilacunarietalia microcarpae ordo nov. hoc loco. They are included in the class Festuco–Brometea Br.-Bl. et Tx. ex Soó 1947.

Biophysical Effects of Evapotranspiration on Steppe Areas: A Case Study in Naâma Region (Algeria)

The Algerian steppe is of great interest in terms of vegetation, mainly in the Naâma region. This steppe vegetation is generally composed of annual and perennial grasses and other herbaceous plants, as well as, bushes and small trees. It is characterized by an arid Mediterranean climate where the average annual precipitation (100 to 250 mm) is insufficient to ensure the maintenance of the vegetation, in which the potential evaporation always exceeds the precipitations. This aridity has strong hydrological effect and edaphic implications from which it is inseparable. Water losses are great than gains due to the evaporation and transpiration from plants (evapotranspiration). The wind moves soils for one location to another, and causes a strong evapotranspiration of the plants, which is explained by a strong chronic water deficit of climatic origin of these compared to the potential evapotranspiration, opposed to a humid climate. Evapotranspiration is certainly closely linked to climate factors (solar radiation, temperature, wind, etc.), but it also depends on the natural environment of the studied region. Potential evapotranspiration (PET) data estimated from Thornthwaite’s method for the three stations (Mécheria, Naâma and Ainsefra). The average annual value of potential evapotranspiration is of the order of 807 mm in Mécheria, of 795 mm in Naâma de and in Ainsefra of 847 mm. It is more than 3 times greater than the value of the rainfall received. This propels it globally in the aridity of the region and from which the water balance of plants is in deficit. The potential evapotranspiration of vegetation in arid areas is very important due to high temperature and sunshine. During the cold season, precipitation covers the needs of the potential evapotranspiration and allows the formation of the useful reserve from which the emergence of vegetation. From the month of April there is an exhaustion of the useful reserve which results of progressive deficit of vegetation. Faced with this phenomenon of evatranspiration, the steppe vegetation of the region then invests in “survival” by reducing the phenomena of evapotranspiration, photosynthetic leaf surfaces, in times of drought. These ecophysiological relationships can largely explain the adaptation of steppe species (low woody and herbaceous plants) to the arid Mediterranean climate. Mechanisms and diverse modalities were allowing them to effectively resist for this phenomenon. The adaptation of the steppe vegetation by the presence of a root system with vertical or horizontal growth or both and seems to depend on the environmental conditions, and by the reduction of the surface of transpiration, and by the fall or the rolling up of the leaves, and by a seasonal reduction of transpiration surface of the plant to reduce water losses during the dry season (more than 6 months) of the year.. Some xerophytes produce “rain roots” below the soil surface, following light precipitation or during dew formation. Other persistent sclerophyllous species by which decreases transpiration by the hardness of the leaves often coated with a thick layer of wax or cutin.

Paleo-Ecology of the Yedoma Ice Complex on Sobo-Sise Island (EasternLena Delta, Siberian Arctic)

Late Pleistocene permafrost of the Yedoma type constitutes a valuable paleo-environmental archive due to the presence of numerous and well-preserved floral and faunal fossils. The study of the fossil Yedoma inventory allows for qualitative and quantitative reconstructions of past ecosystem and climate conditions and variations over time. Here, we present the results of combined paleo-proxy studies including pollen, chironomid, diatom and mammal fossil analyses from a prominent Yedoma cliff on Sobo-Sise Island in the eastern Lena Delta, NE Siberia to complement previous and ongoing paleo-ecological research in western Beringia. The Yedoma Ice Complex (IC) cliff on Sobo-Sise Island (up to 28 m high, 1.7 km long) was continuously sampled at 0.5 m resolution. The entire sequence covers the last about 52 cal kyr BP, but is not continuous as it shows substantial hiatuses at 36–29 cal kyr BP, at 20–17 cal kyr BP and at 15–7 cal kyr BP. The Marine Isotope Stage (MIS) 3 Yedoma IC (52–28 cal kyr BP) pollen spectra show typical features of tundra–steppe vegetation. Green algae remains indicate freshwater conditions. The chironomid assemblages vary considerably in abundance and diversity. Chironomid-based TJuly reconstructions during MIS 3 reveal warmer-than-today TJuly at about 51 cal kyr BP, 46-44 and 41 cal kyr BP. The MIS 2 Yedoma IC (28–15 cal kyr BP) pollen spectra represent tundra-steppe vegetation as during MIS 3, but higher abundance of Artemisia and lower abundances of algae remains indicate drier summer conditions. The chironomid records are poor. The MIS 1 (7–0 cal kyr BP) pollen spectra indicate shrub-tundra vegetation. The chironomid fauna is sparse and not diverse. The chironomid-based TJuly reconstruction supports similar-as-today temperatures at 6.4–4.4 cal kyr BP. Diatoms were recorded only after about 6.4 cal kyr BP. The Sobo-Sise Yedoma record preserves traces of the West Beringian tundra-steppe that maintained the Mammoth fauna including rare evidence for woolly rhinoceros’ presence. Chironomid-based TJuly reconstructions complement previous plant-macrofossil based TJuly of regional MIS 3 records. Our study from the eastern Lena Delta fits into and extends previous paleo-ecological Yedoma studies to characterize Beringian paleo-environments in the Laptev Sea coastal region.

New and validated names of some syntaxa of the Festuco-Brometea class vegetation from Eastern Europe

We present new and validated names of some syntaxa of the vegetation class Festuco-Brometea. True steppe vegetation of Eastern Europe, which is distributed from the Eastern part of Romania to the Urals, we propose to consider as a separate order Galatello villosae-Stipetalia lessingianae. It is an intermediate link between meso-xeric communities of the Central and Eastern Europe of the order Festucetalia valesiacae Soo 1947 from one hand, and desert steppe vegetation of the order Tanaceto achilleifolii-Stipetalia lessingianae Lysenko et Mucina in Mucina et al. 2016 from the other hand. We describe a new order Cephalario uralensis-Jurineetalia stoechadifolii for rocky dwarf-shrub calcareous grasslands of the Pontic region. It replaces the order Stipo pulcherrimae-Festucetalia pallentis Pop 1968 in Eastern Europe due to more continental conditions. We validate the name of the alliance Galio campanulati-Poion versicoloris, as well as its type association. This alliance includes rocky grasslands on limestone outcrops from the Central and Western Podillia and belongs to the order Stipo pulcherrimae-Festucetalia pallentis Pop 1968 on the easternmost range of its distribution. We describe a new association of the desert steppes from the Republic of Kalmykia of the alliance Tanaceto achilleifolii-Stipion lessingianae. In addition, we publish the replacement name Paeonio tenuifolii-Stipetum tirsae as a substitute for illegitimate later homonym. У статті наводиться опис нових, а також відбувається валідизація деяких синтаксонів рослинності класу Festuco-Brometea. Запропоновано справжні степи Східної Європи, поширені від східної частини Румунії до Уралу, відносити до порядку Galatello villosae-Stipetalia lessingianae. Він є проміжною ланкою між мезоксерофітними угрупованнями Центральної та Східної Європи порядку Festucetalia valesiacae Soo 1947 та пустельними степами порядку Tanaceto achilleifolii-Stipetalia lessingianae Lysenko et Mucina in Mucina et al. 2016. Кальцепетрофітні угруповання Понтичного регіону запропоновано об’єднати у порядок Cephalario uralensis-Jurineetalia stoechadifolii. Вони заміщають ценози Stipo pulcherrimae-Festucetalia pallentis Pop 1968 у Східній Європі в умовах більш континентального клімату. Валідизовано союз Galio campanulati-Poion versicoloris, що охоплює угруповання на карбонатних відслоненнях Центрального та Західного Поділля, і є одиницею порядку Stipo pulcherrimae-Festucetalia pallentis Pop 1968 на східній межі поширення, а також асоціацію, що є його лектотипом. Описано нову асоціацію пустельних степів з Республіки Калмикія з союзу Tanaceto achilleifolii-Stipion lessingianae. Окрім того, наведено нову назву Paeonio tenuifolii-Stipetum tirsae для асоціації лучних кримських степів, оскільки стара її назва має бути відхилена внаслідок омонімії.

Ecological turnover and megafaunal ghost ranges during the Pleistocene-Holocene transition in central Yukon, Canada as revealed by palaeoenvironmental DNA

<p>The multitude of factors alleged to have contributed to the late Quaternary mass extinction of some two-thirds of Earth’s megafauna is complicated by the coarse record of buried macro-fossils. In response, micro-methods such as ancient DNA have been increasingly able to augment discontinuous palaeontological records to investigate the relative timings of vegetation turnover versus megafaunal extirpations—all in the absence of biological tissues. Here, we present sedimentary ancient DNA data retrieved using the PalaeoChip Arctic-1.0 bait-set diachronically identifying fauna and flora from permafrost cores recovered from the Klondike region of central Yukon, Canada dating between 30,000–6000 calendar years BP. We observe a substantial turnover in ecosystem composition between 13,000–10,000 BP with the rise of woody shrubs and the disappearance of mammoth-steppe vegetation. We also identify a lingering signal of <em>Equus</em> sp. (North American horse) and <em>Mammuthus primigenius</em> (woolly mammoth) from multiple samples thousands of years after their last dated macro-fossils, possibly as late as the mid-Holocene.</p>

Estimation of the relation of NDVI steppe vegetation and radial growth of pine belt forests in arid conditions of the south of Western Siberia

This article presents a spatial-temporal analysis of the NDVI vegetation series (based on the MODIS satellite data) and dendrochronological data obtained for the steppe regions of the Altai Territory. NDVI series are built for five polygons of natural and natural-anthropogenic steppe landscapes for the period 2000–2018. Experimental areas of natural landscapes are located in coastal and specially protected natural areas, natural and anthropogenic arable lands. Most of the points are located in the dry-steppe sub-provinces of the steppe zonal area, a smaller part is in the arid-steppe (including the dendrochronological area). The chronology of the tree ring width is built for the Scots pine in the steppe part of extrazonal belt pine forests. A positive trend in vegetation indices change and a weak positive trend for the tree-ring chronology of the pine were found for the NDVI series of almost all polygons for the study period. A more pronounced positive trend is characteristic of the area with the lowest average NDVI values, while a negative trend is characteristic of the area with the highest average values of the vegetation index. The correlation of the NDVI series averaged over polygons with each other ranged from 0.54 to 0.64 (significant at p < 0.05). The dependence of the analyzed series on the dynamics of moistening of the territory was revealed. The correlation coefficients of the Selyaninov hydrothermal coefficient with the NDVI series ranged from 0.51 to 0.76, and with the tree-ring chronology was 0.63 (significant at p < 0.05). A statistically significant relationship was established for some points between the chronology of the pine and the NDVI series, mostly related to dry steppe vegetation.