CHANGES IN THE STRUCTURE AND ABOVEGROUND BIOMASS OF STANDS IN THE TRANSITION ZONE BETWEEN THE FOREST AND MOUNTAIN STEPPES IN THE KRAKA MASSIF, SOUTH URALS

The structure of tree stands in the ecotone between the forest and extrazonal steppes on southern slope the South Kraka mountain range (eastern macro slope of the South Urals) was investigated. On the basis of taxation data and the identified close relationships between the biomass of trees and the diameters of their trunks, aboveground biomass of stands was calculated. It has been shown that the deterioration of microclimatic and soil conditions for the growth and regeneration of trees in the transition zone between the forest and mountain steppes leads to a significant change in taxation characteristics and aboveground biomass of tree stands.

Cousinia sharifii, a new species of Cousinia sect. Cynaroideae (Asteraceae) from NW Iran

A new species of Cousinia (sect. Cynaroideae Bunge) is described and illustrated. Cousinia sharifii was found in mountain steppes near the border between Iran (W Azarbaijan) and Turkey. It is related to the complex of C. canescens s.l., in which it can be distinguished by the shape of involucre and phyllaries, and by the number of flowers and phyllaries. A distribution map, a line drawing and a scanned image of the type specimen of the new species are provided.

Distribution Patterns of Grasshoppers and Their Kin in the Boreal Zone

The distribution patterns of Orthoptera are described for the boreal zone. The boreal fauna of Eurasia includes more than 81 species. Many of them are widely distributed. The monotypic genusParacyphoderrisStorozhenko and at least 13 species are endemics or subendemics. About 50 species are known from boreal North America. Four endemic species are distributed very locally. Relationships between the faunas of the Eurasian and North American parts of the boreal zone are relatively weak. The boreal assemblages are usually characterized by the low levels of species diversity and abundance. Grasshoppers and their relatives occupy almost exclusively open habitats, such as different types of meadows, mountain steppes and tundras, clearings, openings, bogs, and stony flood plains. The local endemics and subendemics are found only in some habitats of the eastern part of Eurasia and the north-western part of North America. Retrospective and prospective of the boreal fauna of Orthoptera are also discussed.

Germination of fresh and frost-treated seeds from dry Central Asian steppes

We tested the germination of fresh and frost-treated seeds of 26 species of southern Mongolian mountain and desert steppes, covering the major growth forms of woody and herbaceous perennials and short-lived species in the region. In the field, germination depends on rains that are largely restricted to the summer months between June and August. Thus, germination tests were performed at alternating conditions of 10°C in darkness and 20°C in light (12 h/12 h), which correspond to temperatures at the study site in early and late summer. Seeds of both woody and herbaceous perennials germinated well under the chosen conditions and apparently did not require stratification or scarification. In contrast, germination of annual species was mostly below 30%, while seed viability was equally high in all three growth forms. Winter conditions, simulated by freezing dried seeds at −18°C, hardly changed seed germination in the perennial species, but several short-lived species responded with increased germination. Short-lived species are not abundant in the real vegetation, which is governed by perennials. Thus, we conclude that the important species in Mongolian mountain steppes germinate readily without a dormancy-breaking treatment. A review of the available literature revealed that a complete lack of dormancy, or presence of only conditional dormancy, is also widely described for other species of Central Asian deserts and steppes, which is in contrast to data from North American prairies.

The map of steppe vegetation of Eastern Transcaucasus region

Mountain steppes play important role in vegetation cover of East Transcaucasus. They have some similar floristic and phytocoenotic features with North Caucasus and Black Sea plain steppes, but by origin they related to the South-West Asian steppes. The characteristic feature of these steppe communities (especially the middle-height mountain ones) is the participation of xerophytic cushion-like thorn-dwarf semishrubs and shrubs (species of gg. Acantholimon, Astragalus). The main subdivisions of the legend show altitudinal subtypes of steppe vegetation: piedmont and lowmountain sagebrush-bunchgrass desert steppes; piedmont and low-mountain herb-bunchgrass and bunchgrass true steppes; low– and middle–height mountain xerophytic dwarf semishrub and shrub and shrub-bunchgrass (tragacanth, thyme) steppes; middle-height and high-mountain herb-grass and grass-herb meadow steppes. The main mapping units are associations or groups of ecologically similar associations. The most wide-spread dominants of Transcaucasus steppes are Bothriochloa ischaemum, Stipa tirsa, S. pennata, S. pontica, S. capillata, Festuca valesiaca, etc. This map is of considerable significance as the areas of natural steppe vegetation are the models for ecological monitoring and the objects of study and protection.