Arid Ecosystems最新文献

The taxonomic structure of the flora of the Archedinsko-Donskoi sandy massif is analyzed and rare species are identified. The novelty of this research lies in obtaining new data for adjusting schemes of botanical–geographical zoning of steppe territories in the southern part of Russia as a whole and the distribution area of sandy massifs in particular. The formation of the floristic list was based on data obtained during field surveys conducted between 2016 and 2024, as well as from the flora list available in the Global Biodiversity Information System (GBIF) of the INaturalist platform, which contains information on plant findings for the period from 1990 to 2024. It has been established that the current floristic list of the sandy massif comprises 677 species from 324 genera and 95 families, belonging to eight classes and seven divisions. The division Magnoliophyta is the most represented, accounting for 79% of the flora of the territory. The overall generic coefficient is 2.09. The highest generic coefficients are observed in the families Amaryllidaceae (11.0), Plantaginaceae (8.25), Cyperaceae (6.8), Juncaceae (6.0), Salicaceae (5.0), and Violaceae (5.0). The leading position in the flora is held by the family Asteraceae, represented by 103 species (15.2%), and the family Poaceae, which includes 68 species (10.0%). A large number of taxa are also characteristic of the families Cyperaceae (34), Plantaginaceae (33), Caryophyllaceae (32), Fabaceae (31), Lamiaceae (29), Brassicaceae (22), Rosaceae (20), and Amaranthaceae (17). The sandy landscapes of the Archedinsko-Donskoi massif with elements of boreal flora, confined to reservoirs, floodplain areas, and areas with an atypical water regime, are a unique object for the conservation and maintenance of the biological diversity of steppe territories. Here 30 species listed in the Red Book of Volgograd Oblast (2017) and 12 species listed in the Red Book of the Russian Federation (2008) were identified. They are under threat of extinction: Aldrovanda vesiculosa L., Lycopodiella inundata (L.) Holub., Lycopodium clavatum L., Climacium dendroides (Hedw.) Web. et Mohr., and Clematis orientalis L. The largest list of Red Book representatives is represented by the families Asteraceae (three types) and Orchidaceae (four types). The research results can be useful in studying the ecology of plant communities and the species in them, for the restoration and preservation of lost biological diversity of the vegetation cover of sandy ecosystems.

For the first time, comparative data on the taxonomic composition of cyanobacterial and algal communities of eroded soils in the Fergana Valley (Uzbekistan), which were obtained using morphological analysis and microbiological profiling, are presented. The characteristic features of the algal flora of the eroded soils of the Rezoksai ravines, compared to the soils of the Levye Hills, were the presence of yellow–green algae, the absence of heterocytic cyanobacteria capable of nitrogen fixation, an increase in the proportion of monadic forms and/or algae capable of zoosporogenesis, and generally lower taxonomic richness and diversity of algae. Light microscopy was shown to confirm in part the diversity of cyanobacteria and algae in the studied soils estimated by high-throughput sequencing, but only detected in about half of the taxa. However, the presence of yellow–green algae was demonstrated solely by light microscopy and not by metabarcoding. The use of the V3–V4 region of the chloroplast 16S rRNA gene allowed us additionally to identify genera of green algae in the algal flora such as Edaphochlorella, Pseudomuriella, Watanabea, as well as diatoms of the genera Bacillaria, Fistulifera, Entomoneis, and charophyte algae Klebsormidium. Nevertheless, approximately 20% of algae remain unidentified due to the lack of reference sequences for the green microalgae ITS2 in genetic databases.

The bioclimatic conditions of soil formation in the cryoarid climate zone of Western Transbaikalia determine the specific composition of humic substances, but the heterogeneity of these compounds, as well as the widely used classical methods of organic matter analysis, does not allow us to judge with sufficient confidence the structure of high-molecular organic compounds in soils. ¹³C-NMR spectroscopy of humic acid preparations from chestnut soils made it possible to identify the ranges of chemical shifts belonging to carbon atoms of various functional groups and molecular fragments. The peculiarity of the humus formation process in chestnut soils is that, despite the harsh conditions of soil formation (the influence of long-term seasonal permafrost, continental climate), humic acids with a fairly high content of C, N, and O are formed. Macromolecules of humic acids in arable samples of chestnut soils are characterized by a less developed peripheral part and a high benzenoid index compared to humic acids of the virgin variant, which is due to the environmental conditions of soil formation and the component composition of humification precursors. An increase in the proportion of aliphatic structures and a decrease in the proportion of aromatic fragments allow us to talk about a simplification of the structure of humic acid macromolecules. A short growing season and insufficient moisture in combination with a light granulometric composition significantly reduce the rate of transformation of organic matter and lead to an increase in the proportion of unoxidized aliphatic fragments.

The properties of soils, C-biomass, and the structure of humic acids of arable chestnut soils of Western Transbaikalia were studied. The objects of this study were arable chestnut soils of the southern basins of Western Transbaikalia (Tugnuyskaya basin, Selenginskaya basin, Ivolginskaya basin). For comparison, arable soils were studied in pairs with virgin soil analogues. Arable chestnut soils are characterized by low fertility: low humus content of 0.98 ± 0.07%, low total nitrogen content of 0.08 ± 0.01%, arable horizon thickness of 21.33 ± 2.31 cm, and a light loamy granulometric composition. During the growing seasons, the average biomass carbon accumulation rates in chestnut soils were 35.77 ± 3.09 mg C/100 g of soil. The share of C-biomass in the total stock of soil organic carbon for the studied soils is up to 2.5%. The content of aliphatic carbon in arable chestnut soil is also lower than in virgin soil. The content of the amino group and methoxyl group carbon in virgin soil is 7.9 ± 0.14%; in arable soils this indicator is almost two times lower. The amount of carbon in carboxyl groups is 15.5 ± 0.42% in arable chestnut soils; in virgin soils the indicator was 12.55 ± 0.92%. Spectrum analysis of ¹³C-nuclear magnetic resonance (NMR) spectroscopy of humic acids (HAs) in soils can provide important information on the chemical composition and structural features of organic matter in soils. For arable and virgin chestnut soils of Transbaikalia, such an analysis can reveal differences associated with the use of land in agriculture. Aliphatic carbon in the HA of arable soil is expressed less strongly, which indicates a greater role of aromatic carbon in its macromolecular structure. A pattern is observed: in arable lands the content of aliphatic compounds is lower than in virgin lands. It has been found that agricultural tillage leads to a change in the molecular structure of humic acids, which is expressed in an increase in the proportion of aromatic carbon in arable soil. In the elemental composition of HA in cultivated chestnut soils of Transbaikalia, the carbon content is higher and the hydrogen content is lower compared to virgin analogues. The high hydrogen content in virgin soils leads to relatively developed lateral carbon chains in HAs. In cultivated chestnut soil, the HA macromolecule contains more nitrogen (2.9 at %) than in virgin soil (2.7 at %). The atomic ratio H : C in cultivated chestnut soil was 1.0, while in virgin soil it was 1.1. In cultivated variants, the degree of benzenoid content (BC) is 22.5, while in virgin soil the indicator is lower at 16.4. It was established that the elemental composition of cultivated chestnut soils is characterized by a more condensed structure compared to virgin soils.

The aim of this work was to identify patterns in the distribution of species diversity of allergenic and poisonous plants across the floristic regions of the Republic of Kazakhstan. As a result of this research, 51 of the most toxic species of vascular plants belonging to 34 families were identified on the territory of the republic. The list of allergenic plants includes 59 species belonging to six families. An additional analysis of the distribution patterns of allergenic and poisonous plants was conducted, based on their relationship with leading environmental factors. The positive relationship between the number of allergenic species and the aridity index values shows that an increase in the number of allergenic species occurs with an increase in climate humidity. The high correlation between the number of poisonous species and the average annual precipitation suggests that the number of poisonous species increases with an increase in floristic diversity in the arid and semi-arid regions of Kazakhstan. The conducted cartographic analysis showed that the greatest number of allergen species of different groups blooming from spring to autumn includes the following floristic regions: forest–steppe, arid steppes, dry and desert steppes, and northern deserts and mountains. The greatest number of poisonous plant species is found in mountainous regions with high floristic diversity.

The specificities of heat availability and crop demands for the sum of temperatures above 10°C on the territory of the Ararat Valley and its foothills are discussed. The patterns of multiyear fluctuations of heat availability are assessed in the context of the global climate change, and forecasts are made. The daily actual observations of data from nine meteorological stations located in the area studied along with the agroclimatic reference books and yearbooks were used. Mathematical statistical, extrapolation, analytical, and correlation methods were applied. It has been demonstrated that heat supply conditions in the region are favorable for the growth and development of various crops, although the danger of late spring and early autumn frosts should be taken into account. It has been shown that heat availability is unevenly distributed across the territory studied, and it decreases naturally with increasing altitude, changing from 4486 to 3012°C and lower with the vertical gradient of 175°C/100 m. The interannual course shows an increasing trend in heat availability, which actually increased by 428°C, on average, from 1993 to 2022. This is favorable for cultivation and expansion of sown areas of many new thermophilic and drought-resistant varieties of high-yielding crops.

The forest–steppe is an ecotone characterized by a combination of forest and steppe ecosystems. In the European part of Russia, there are three forest–steppe biomes: the Dnieper–Volga (forest–steppe part), Trans-Volga, and Crimean–Caucasian. All of them have now been largely transformed by man. One of the most important components of forest–steppe biocenoses is rodents. This work describes the fauna of rodents in the forest–steppe of the European part of Russia. A general list of rodent species in the area under consideration was compiled. The taxonomic composition, geographic, ecological, and other elements of the rodent fauna were identified, and similarities and differences in the composition of the rodent fauna of forest–steppe biomes were assessed. In total, 44 species of rodents have been reliably recorded (35 in the Dnieper–Volga biome, 27 in the Trans-Volga biome, 26 in the forest–steppe of the North Caucasus, and 20 in the forest–steppe of Crimea). In the zonal forest–steppe, 37 species were noted, and in the barrier (Caucasus and Crimea), 30. Representatives of the Muridae (25%) and Critecidae (36%) families dominate. The predominant species are Eurasian steppe (21%), Euro-Siberian (18%), European forest (14%), and European steppe (14%) species. There were 17 steppe and desert–steppe species (39% of the total number), and 13 forest species (30%).

Forests of Schrenk spruce (Picea schrenkiana Fisch. et C.A. Mey.) in Kyrgyzstan are widespread in the Inner, Central, and Northern Tien Shan. Small plots of spruce forest are also found in Pamir-Alai. They play a great water regulation, soil protection, sanitary–hygienic, and recreational role. The distribution, location, and change in the aspect of P. schrenkiana in the upper sub-belt of spruce forests of the Inner Tien Shan on the slopes of the Moldo-Too Ridge are analyzed in this work. Most researchers point out that the upper limit of spruce distribution was previously at the altitude of 2900–3100 m above sea level BS. Our monitoring data show that its top boundary is now located at an altitude of 3324 m above sea level. The revealed new limit of P. schrenkiana, in our opinion, is related to climate change.

This paper presents data on the current state of the population and long-term dynamics of the steppe marmot (Marmota bobak Müller, 1776) population in the Burtinskaya Steppe Site of the Orenburg State Nature Reserve (Orenburg Region, Belyaevsky District). The studies were conducted in the periods 1998–2001 and 2021–2022, and archival data on the steppe marmot census of the reserve were also used. The influence of air temperature and precipitation on the number of marmots, population growth, and brood size was analyzed. Over the entire observation period, three peaks were identified in the dynamics of the steppe marmot population. The first two peaks in numbers in 2000 and 2009 were approximately equal to each other (395–401 individuals); the third, significantly smaller peak (187 individuals) was observed in 2017, and in 2019 the number of marmots reached the minimum for the entire observation period—81 individuals. In 2022, the total number of marmots almost doubled and amounted to 179 individuals. Fluctuations in numbers occurred due to changes in both the number of families and the number of individuals and the composition of families. The maximum number of adult marmots exceeded the minimum by 3.2 times, while the number of yearlings was 28.3 times higher. The population growth was below 40% for half of the observation period, and the average brood size was 2.3 ± 0.16 individuals. A negative correlation was found between the number of marmots and air temperature, and a positive correlation was found between the number of marmots and the amount of precipitation. The combined effect of fires and droughts has a negative impact on the food supply of marmots, which often leads to an almost twofold decrease in numbers the year after the fire.

Wildfires are a typical phenomenon for the steppes of Northern Eurasia and a threat to environmental security at the regional and global levels. To understand the causes of fires, the author proposes a methodology for mapping fire sites and subsequent data analysis using the example of a territory located in the steppes of the Southern Trans-Urals. Source materials for the data were collected using Landsat (1984–2021) and MODIS (2000–2021) satellite images, geospatial data based on them, morphometric features of burnt areas, and meteorological data at the time of fire spread. For the period 1984–2021, 738 fire sites were identified and their density was calculated. Classification was carried out in relation to their position as anthropogenic and natural objects. It was found that 51.6% of outbreaks were confined to poorly developed agricultural lands (pastures, hayfields, and fallow lands of different ages), 21.8% to highways, and 13.6% to cultivated arable lands. A sharp deterioration in the fire situation has been observed since 1999 to the present day, which is due to a reduction in agricultural production, restoration of vegetation cover of degraded pastures, and defragmentation of arable land. A regional feature is the lack of a tendency towards a reduction in fires due to the onset of a low-water period (2012–2021), accompanied by the drying up of the vast lake basins of the Southern Trans-Urals and Turgai. The listed factors caused the fires to spread more widely, while the main locations of the outbreaks remained unchanged. It was determined that, despite the worsening fire situation, since 2005 the effectiveness of fire prevention measures taken to protect the Ashchisayskaya Steppe Nature Reserve has increased. The approaches developed for identifying the position and analyzing the distribution of fire sources can be recommended for assessing pyrogenic threats and optimizing fire prevention measures.