Ашық рұқсат
Рұқсат берілді
Тек жазылушылар үшін
Том 7, № 1 (2017)
- Жылы: 2017
- Мақалалар: 10
- URL: https://ogarev-online.ru/2079-0961/issue/view/12821
Applied Problems of Arid Lands Development
Phytocenotic characteristic of the Achnatherum splendens (trin.) Nevski communities of western Transbaikalia
Аннотация
The phytocenotic characteristics of cheegrass (Achnatherum splendens (trin.) Nevski) communities developed on solonchaks in the haloxerophytic steppe of western Transbaikalia are given. The specific features of their composition and structure have been revealed. The similarity of the species composition of cheegrass communities is slight or medium. The botanical composition accounts for 14 species of halophytes and 17 species of halotolerant glycophytes. The communities and their production are mainly formed by three to four species, including the dominants. The production of the cheegrass communities is at a normal level (1626 g/m2 per year).
31-40
Topical and trophic structure of midsummer zooplankton in saline rivers in the Elton Lake basin
Аннотация
In August 2013, 17 taxa of zooplankton in the rank of species (Cladocera, Cyclopoida, Calanoida, and Rotifera) and three taxa of meroplankton (Mollusca, Diptera, and Heteroptera larvae) were identified in the zooplankton of six small rivers in the basin of Lake Elton with a mineralization of 6–32 g/L. Benthoplankton formed most of the list (45% of species); euplankton constituted only 20%. Three trophic levels were distinguished in the community: peaceful phyto- and bacteriodetritophages, omnivorous animals with different body sizes (<1.5 and 1.5–6 mm), and predators. The effect of salinity on the zooplankton structure, the biotopical distribution of species, the features of trophic relations, and the food supply of predators are discussed.
59-68
Plant communities of the lower reaches of the Volga River on soils with strongly seasonal dynamics of salinization
Аннотация
The database EU-RU-002 of the Lower Volga valley vegetation plots has been analyzed. The database contains the characteristics of 15029 relevés located in the region in the period from 1924 to 2013. Two associations, Alismato‒Salicornietum Golub 1985, and Crypsido aculeatae‒Salsoletum sodae ass. nova, have been discovered. These associations include halophytes and glycophytes on the same sample plots. Analysis of water extracts from soil samples made it possible to determine significant dynamics of the toxicity of a soil solution during the year. These changes are related to the hydrological regime of the Volga River.
23-30
Analysis of the current status of populations of rare plant species of nature monument Troicki chalk mountains (Orenburg region)
Аннотация
the results are presented for the study of four rare species in the Troicki chalk mountains: Anthemis trotzkiana Claus., Matthiola fragrans Bunge, Lepidium meyeri Claus, and Zygophyllum pinnatum Cham. The total density of the studied coenopopulations ranged from 2.2 to 6.1 copies/m2, and the effective density was 1.5–4.2 copies/m2. Coenopopulations are normally incomplete, most typically lacking the spectrum of seedlings, juvenile and senile individuals, and generative individuals that peak in middle-age. Coenopopulations Anthemis trotzkiana lack postsenile individuals. By the “delta-omega” classification, coenopopulations Anthemis trotzkiana, Matthiola fragrans are growing old, Lepidium meyeri are transitional, and Zygophyllum pinnatum are mature. The indices of recovery and senescence are 0.03–0.36 and 0.03–0.72, respectively. High levels of variability and plasticity of morphometric characters have been registered.
41-48
Distribution and ecological features of Peganum harmala L. in the environs of Lake Baskunchak (Astrakhan oblast)
Аннотация
The modern distribution of Peganum harmala (Peganum harmala L.) in the environs of Lake Baskunchak (including the Bogdinsko–Baskunchakskiy Nature Reserve), where the species has been found for the first time, is shown. The distribution trends of the species and its indicator role in assessing the state of natural ecosystems in the area under study are discussed.
49-51
History of research on biodiversity in Crimean hypersaline waters
Аннотация
The paper reviews the history of research on the biodiversity of hypersaline waters in the Crimean arid zone from the end of the 18th century to the present. Summing up the accumulated knowledge on biodiversity of these water bodies, the authors have noted the presence of 290 species of eukaryotic organisms, including 190 unicellular ones, and nearly 200 species of bacteria and archaea, of which at least 100 species are represented by cyanobacteria. It has been concluded that the diversity of both prokaryotic and eukaryotic organisms is still understudied. This paper is not an exhaustive review of the history of research on the biodiversity of Crimean hypersaline waters; it is rather a prelude to such a historical study, as well as a call for a broadening and deepening of the scientific knowledge of the unique biodiversity in these extreme habitats.
52-58
New record of Rhinopoma cystops Thomas, 1903 (Mammalia, Chiroptera) in arid southwestern Sahara of Algeria
Аннотация
In January 2015, a colony of approximately 50 individuals of Rhinopoma cystops was found, and 10 Asellia tridens were netted in a cave of Béchar, Algeria, near the border with Morocco, southwestern Algerian Sahara. These two species were recorded previously in Algeria, but Rhinopoma cystops has been registered in Béchar for the first time. Therefore, information regarding the distribution and geographic variation of this species are also provided in the present study.
69-71
Systematic Study of Arid Territories
Biological activity of anthropogenic mountain soils of medieval agricultural terraces of mountainous Dagestan
Аннотация
The study of agricultural terraces in mountainous Dagestan that date to the Middle Ages revealed the polygenetic character of anthropogenic soils, which reflects the main stages of their evolution. In light of their long-term burial, the soil layers of the preanthropogenic stage of evolution were characterized by fairly high values of biological activity, with the exception of the biomass of fungal mycelium, a small amount of which remained. At the early agrogenic stage, soil plowing without irrigation did not significantly change their microbiological properties; however, the increase in urease activity in some studied profiles may indicate that cattle fertilizers were applied in some areas of the terraces. During the Little Ice Age (the 16–18th centuries A.D.) the terraces were abandoned, which led to the accumulation of organic carbon in the soils as a result of the fallow process, as well as an increase in their enzymatic activity. The second agrogenic stage with irrigation was characterized by a noticeable growth in the active microbial biomass, the soil phosphatase activity, and, in particular, the urease activity, which may indicate that farming was intensive and organic fertilizers were applied. In the last 20 years, the development of terraces under natural conditions led to a noticeable growth in the biological activity of upper fallow horizons. However, the urease activity significantly decreased in nonirrigated areas, whereas the indicators of microbial biomass remained at the same level.
1-10
Components of C and N cycles in natural and anthropogenic ecosystems of semideserts of the northern Caspian area
Аннотация
Changes in the amounts and dynamics of the deposition of carbon and nitrogen in the soil surface of anthropogenic pasture and forest ecosystems created in places of natural steppe and desert plant associations in the Northern Cis-Caspian area were studied. For two years after input, the litter of oak stands (Quercus robur) deposited 1.3 times more carbon and about the same amount of nitrogen as compared to the steppe litter, even though the mass of litter input in the forest plantation was 1.4 times less than that in the grass ecosystem. The values of carbon and nitrogen contents in the soil under steppe vegetation and under plantation were similar, but there was a redistribution of carbon and nitrogen contents in the forest soil. The carbon contents in the forest litter and 0–5 cm layer make up 33% of the contents in the litter and in 0–50 cm soil layer. The respective value was 22% under the steppe vegetation; the nitrogen contents were 2.9 and 2.0%, respectively. Due to intensive grazing, the ecosystems of microdepressions obtain 1.6–1.7 times less carbon and nitrogen than those of virgin plots. This value was 1.4 for the ecosystem of microelevations. A significant decrease in the contents of carbon and nitrogen was observed in the litter and 0–5 cm layer of meadow–chestnut soils of microdepressions under the pressure of intensive grazing.
11-18
The impact of droughts on the mineralization of reservoirs in northeastern Brazil
Аннотация
The climatic features of northeastern Brazil result in the almost complete absence of river runoff during drought periods. The extreme irregularity of runoff in the reservoirs of the region leads to an increase in water salinity by the end of the drought. The degree of mineralization growth with respect to the reservoir volume at the beginning of the dry period and the amount of water abstraction from this reservoir during this period was estimated via the calculation of water mineralization for conditions in which there is no flow to reservoirs. These estimates are presented in the form of graphical calculation diagrams for three reservoirs of the Brazilian Ceará state.
19-22