Steppe Species Research Articles

Features of the biomorphological and geographic structure of segetal floras in a number of regions in Russia

Background. Biomorphological and geographic analyses conducted on long geographic gradients are relevant for identifying botanical and geographic features of segetal floras.Materials and methods. A comparative analysis was used to study biomorphological and geographic elements of segetal floras in nine regions of Russia: Vologda, Leningrad, Novgorod, Sverdlovsk and Rostov Provinces, the Republic of Bashkortostan, the Republic of Crimea, the Udmurt Republic, and Altai Territory.Results. Biomorphological groups in the compared segetal floras contained approximately equal ratios of therophytes and hemicryptophytes, monocarpic and polycarpic herbaceous plants. Meanwhile, the indigenous fraction manifested a higher share of polycarpic herbs (about 60–70%), while monocarpic herbs predominated in the alien fraction (80–90%). For the most part, indigenous plants represented widespread species (Holarctic and Eurasian), mainly plurizonal ones. At the same time, the composition of geographic elements in segetal floras retained the features of their locations. Species of southern distribution prevailed in the segetal flora of Crimea, while Central and East Asian species in Altai Territory. Depending on the zonal arrangement of segetal floras, the shares of boreal, forest-steppe and steppe species changed. The ratios among geographic elements in the alien fractions of the compared segetal floras were relatively stable. The groups of Eurasian and American species were the most numerous.Conclusion. The ratio of life forms (an increased share of therophytes, and a decreased share of phanerophytes) is probably a characteristic feature of the segetal flora, associated with the living environments of plants in agricultural phytocenoses. Geographic analysis confirmed that segetal floras retained their biogeographical features.

Drought Adaptation and Responses of Stipa krylovii Vary Among Different Regions: Evidence From Growth, Physiology, and RNA-Seq Transcriptome Analysis.

In the context of global climate change, exploring how plant adaptation and responses to drought vary among different regions are crucial to understanding and predicting its geographic distribution. In this study, to explore the drought adaptation and responses of the dominant species in the semi-arid Eurasian Steppes and their differences among the different regions in terms of growth, physiology, and RNA-seq transcriptome, Stipa krylovii was chosen as the study material, and a seed source (three regions: eastern, middle, and western regions) × soil moisture treatment (three treatments: control, light drought, and heavy drought) two-factor experiment was conducted. (1) Four growth traits for individuals from the western region were significantly lower than those from the other two regions. By Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analysis on gene expressions of individuals from each treatment, unique enriched pathways were found under heavy drought. (2) The decrease in the number of tillers with the increasing drought was much lower for individuals from the western region than those from the other two regions. The differentially expressed genes (DEGs) of individuals from the eastern, middle, and western regions between heavy drought versus control were 4887, 1900, and 4896. By KEGG functional enrichment analysis, individuals from the eastern and middle regions mainly regulated energy metabolism and metabolism of other amino acids; and those from the western region mainly regulated biosynthesis of other secondary metabolites and carbohydrate metabolism. (3) Clustering analysis based on gene expressions separated the western region from the other two regions under the same drought treatment. This study indicates that drought adaptation and responses of S. krylovii vary among different regions, especially between individuals from the western region and the other two regions. These findings are essential to understanding the adaptive evolution of population and germplasm resource protection for this important species.

ИЗМЕНЧИВОСТЬ ПРИЗНАКОВ И ХАРАКТЕРА ПРОРАСТАНИЯ СЕМЯН ВИДОВ РОДА ALLIUM В ЦЕНТРАЛЬНОЙ ЯКУТИИ

The purpose of research is to study the quality and nature of the germination of seeds of onion species growing in Yakutia. Mature seeds of 5 species of the genus Allium L., A. prostratum, A. ramosum, A. senescens, A. schoenoprasum, and A. splendens, served as material for research. The studies were carried out on the basis of the natural flora collection of the Botanical Garden at the IBPC SB RAS from 2014 to 2021, located in the vicinity of Yakutsk (Central Yakutia), under laboratory conditions in accordance with standard methods. The seeds of the studied onion species differ in shape, size and weight of 1000 seeds. A. schoenoprasum and A. splendens have a triangular seed shape, A. prostratum, A. ramosum and A. senescens have a wide-ovoid shape. By size, the seeds of the studied species are divided into 2 groups: large (weight of 1000 seeds is more than 2 g), – seeds of A. ramosum and A. prostratum, small (weight of 1000 seeds is less than 1.5 g) – A. splendens, A. senescens and A. schoenoprasum. The weight of 1000 seeds of the steppe species A. prostratum, A. ramosum, and A. senescens, as well as the forest A. splendens, are the most stable. In contrast to them, the smallest-seeded A. schoenoprasum exhibits noticeable variability in some years, not exceeding 17 %. The morphometric parameters of seeds are quite stable. The coefficient of variability in the size of seeds of the steppe species does not exceed 7–9 %; the sizes of the seeds of the meadow species A. schoenoprasum are more variable, and in the intermediate position, the forest species A. splendens. The study of the correlation between seed parameters (width, seed length and seed weight) showed that the number of statistically significant correlations between them is insignificant. Correlations between seed parameters and weather conditions were noted only in steppe plants; in the meadow A. schoenoprasum and forest A. splendens, no dependences of size and weight on the weather conditions of the growing season were found. A comparative study of the course of germination of freshly harvested seeds and after 5–6 months of storage in laboratory conditions showed that dry storage improves the quality of seeds. Stored onion seeds, depending on the species increase or retain high laboratory germination to varying degrees and increase their status (germination group) due to earlier and friendlier germination.

Spatio-temporal variation of the endangered Dupont's Lark diet across Iberia and Morocco.

A species' diet is highly dependent on the availability of food resources in space and time, as well as on intrinsic factors such as sex or age. Accurate assessments of variations in the diet composition of bird populations across spatial scales, seasons and demographic groups are essential not only for understanding the basic ecology of species, but also for the conservation of endangered ones. However, our current knowledge about how birds' diet change according to spatio-temporal variations or intrinsic factors is very limited. Here, we used a multi-marker metabarcoding approach to characterize the diet of a declining shrub-steppe passerine, the Dupont's Lark (Chersophilus duponti), throughout a large part of its global distribution range. We also investigated spatial, phenological and sexual variations in its diet. Using markers from two genomic regions (18S and COI), we analyzed fecal samples from 303 adult Dupont's larks from Morocco and Spain during the breeding and non-breeding seasons. Overall, arthropods from the orders Coleoptera, Lepidoptera, Julida and Orthoptera were the main prey consumed by Dupont's Larks. We found that Dupont's Lark diet varied spatially, as well as temporally, reflecting dietary plasticity in response to changes in prey availability across landscapes and the species' phenological periods. High dietary overlap and no differences between sexes were observed, suggesting similar foraging behavior and nutritional requirements in both sexes. This is the first study providing detailed information on Dupont's Lark food ecology over much of its distribution, which is fundamental for the management and conservation of this declining steppe species.

Research on palatability of bait for targeted control of Brandt's vole (Lasiopodomys brandtii) in typical steppes

Chemical control is still the primary means of controlling wild rodent pests in China's grasslands; however current rodenticides are broad-spectrum and pose a risk to several other grassland ecosystems. Improving the precision of grassland rodent pest control and reducing collateral damage to non-target animals is an urgent problem. One solution to this problem is to ensure that bait choices are preferred by specific rodent. However, most studies on the development of rodenticides have neglected bait choice. We focused on Brandt's voles (Lasiopodomys brandtii), the dominant rodent species in the typical steppes of China, in this study. By measuring the percentage of feeding amount (PFA) different baits in a cafeteria setting, we sought to test the palatability of different candidate baits. We found that one of our blend baits was as popular as the wheat bait among Brandt's voles under laboratory conditions. However, our blended bait was preferred to the wheat bait when rodenticide was added. Non-target animals Columba livia, Gallus domesticus, Ovis aries, and sympatric non-target rodents feed less on blended bait than on wheat. We also used field trials to test whether baits were removed by Brandt's voles or PFA of partially consumed baits. In the wild, the removal time and PFA of Brandt's voles for the rodenticide + blend bait were better than those for the rodenticide + wheat bait. Mixing the wheat baits with bromadiolone rodenticide made poisoned baits less attractive to prey species than unpoisoned baits; however, Brandt’s voles were more likely to take the tainted baits than the unpoisoned baits when bromadiolone was added to the blends. Our results suggested that blend bait with 80 % Allium polyrhizum+ 20 % Stipa krylovii was highly palatable to Brandt's voles, did not become less palatable when poisoned with rodenticide, and was less likely to be eaten by non-target species including Columba livia, Gallus domesticus, Cricetulus barabensis, Phodopus campbelli and Ovis aries. Thus, blend bait has the potential to improve the pest management of Brandt's voles in China.

Distribution and ecological features of the weevil <i>Ptochus porcellus</i> Boheman, 1834 (Coleoptera, Curculionidae: Entiminae) in the Russian Plain and the Urals

An analysis of the distribution and ecological features in European Russia of the weevil Ptochus porcellus Boheman, 1834 (Curculionidae), an Eastern Euro-Caucasian — Kazakhstan southern steppe species, is provided. The northern boundary of its range has been established, on the Russian Plain it mainly passes through the very south of the forest-steppe zone, and in the Urals, — along the middle part of the steppe zone. It is shown that in the north of the range the species is associated with the most xerothermic extrazonal habitats with sparse vegetation cover. Information on the host plants of this species has been supplemented.

Delay impacts of ant nests on plant reproductive phenology in a temperate steppe.

Increasing ant abundance associated with climate warming has been observed in temperate ecosystems. However, how enhanced ant activity affects plant development and phenology remains unclear. In this study, individuals of a perennial forb (Potentilla tanacetifolia) during flowering with and without an ant (Proformica) nest were marked to explore the impacts of ant nests on plant growth and phenology in a temperate steppe on the Mongolian Plateau. Ant nests delayed the start and end flowering dates simultaneously and, consequently, had no effect on flowering duration. However, presence of an ant nest postponed the fruiting date of individuals. Nests further increased numbers of aborted flowers and thus decreased fruit set. These observations suggest that the delayed flowering phenology disrupted synchrony between plant reproduction and pollinators and thus reduced pollination efficiency under ant nests. Given the increasing abundance of ants with rising temperatures under climate warming, plant delayed reproductive phenology and reduced reproductive output will potentially have negative consequences for plant fitness and plant-arthropod interactions, with consequent impacts on resistance and resilience of perennial species in temperate steppes under climate change.

Long-term grazing changed the spatial distributions of dominant species in typical steppe of Inner Mongolia

Dominant species occupy a pivotal role in plant community, influencing the structure and function of the ecosystem. The spatial distributions of dominant species can react to the effect of different grazing intensities, thereby reflecting their tolerance and adaptive strategies toward grazing. In this study, geostatistical methods were mainly used to study the spatial distribution characteristics of Stipa krylovii Roshev. and Leymus chinensis (Trin.) Tzvel. species at two interval scales (quadrat size 5 m × 5 m, 10 m × 10 m) and two treatments (free grazing, FG, 1.66 sheep·ha− 1·a− 1; control, CK, 0 sheep·ha− 1·a− 1) in typical steppe of Inner Mongolia. A systematic sampling method was used in each 100 m × 100 m representative sample plots to obtain the height, coverage, and density of all species in the community. The results showed that grazing altered the concentrated distribution of S. krylovii and the spatial mosaic distribution pattern of S. krylovii and L. chinensis while having no effect on the spatial clumped distribution of L. chinensis. It also found that the spatial distributions of dominant species are primarily affected by structural factors, and random factors such as long-term grazing led to a transition of S. krylovii from a concentrated distribution to a small patchy random pattern should not be overlooked. Our findings suggest that long-term grazing alters the spatial distribution pattern of dominant species and that adaptive strategies may be the key for maintaining the dominant role of structural factors.

Accumulation of heavy metals and arsenic in plants in the vicinity of the Chadan coal deposit (Republic of Tuva)

The content of copper, zinc, lead, cadmium and cobalt in plant samples from the vicinity of the Severny dump of the Chadansky coal mine in the Republic of Tuva was studied. Heavy metals in plant samples were determined by the Quantum-2mt atomic absorption spectrophotometer. Due to the extra-arid conditions, the studied area belongs to the zone of risky agriculture and there is developed cattle breeding. It was revealed that vegetation typical for steppe communities is developed on the territory of the Chadan coal deposit, represented by wormwood-cereal, grass-grass-wormwood, grass-wormwood-kovyl, wormwood-grass-grass steppes. In the dumps, deposits of different ages with small-scale, wormwood-cereal communities with typically steppe species are developed. For lead, cadmium and cobalt, the concentrations in vegetation samples from the CER and SWZ sites adjacent to the dump turned out to be close to their background values. The Cu content in the vegetation of the dump sites exceeds the natural content by 2–2,2 times, Zn – 2–2,7 times, Pb – 1,5 times. However, a comparison of the content of Cu, Cd, Zn, Pb, Co in vegetation from 2 sites of the Severny dump and the background territory with MDU for plant feeds showed that their concentrations in the studied samples are much lower than the maximum permissible level.

Photosynthetic response to water stress of the main grass species of southern patagonian steppe, Argentina

Comparative studies of basic physiological performance are needed to give insight of how grass species survive and grow under current and more severe drought predicted in the framework of climate change in arid steppe grasslands. In this study, photosynthetic performance and stomatal conductance (gs) were measured in leaves of six main grass species of southern Patagonian steppe, after exposing plants to different conditions of water availability. There was a negative linear relationship between photosynthesis at light saturation (Pmax) and plant water stress, expressed as pre-dawn leaf water potential (ψpd), mainly explained by the reduction in gs. A negative linear relationship was also observed between the photosynthetic efficiency (α) and the ψpd of plants, but only under moderate to severe water stress conditions. Grass species had different response to water stress graded in the following order: Pappostipa chrysophylla > Festuca gracillima > Rytidosperma virescens > Poa dusenii > Bromus setifolius. These results can assist to understand the natural spatial distribution of these species under arid conditions, to predict their performance under changing climate, and to select proper species for restoration plans in steppe grasslands.

Species richness and dominant functional groups enhance aboveground biomass, with no effect on belowground biomass in Qinghai-Tibet Plateau's grasslands

Understanding the role of plant diversity in maintaining grassland ecosystem functioning is of great importance in ecological research. Despite decades of research, ecologists have struggled to understand the biodiversity-ecosystem functioning relationships and how the dominance of plant functional groups impacts ecosystem function. In attempting to understand (i) the temporal patterns of above- and below-ground biomass (AGB and BGB) and species richness, (ii) whether species richness is consistently associated with AGB and BGB, and (iii) the relative contributions of plant functional groups (forb, grass, legume, and sedge) in stabilizing ecosystem function, we used biomass productivity data of meadow steppe and alpine meadow in the Qinghai-Tibet Plateau (QTP) for the period 2015–2019. Our results show that AGB for both grasslands increased, but BGB stayed steady over 5 years. The rising tendency of AGB was caused by the upward trend of AGB in forbs and grasses, which are the dominant functional groups in QTP, stressing the importance of dominant functional groups to ecosystem functioning. The biodiversity-ecosystem functioning relationships were significantly positive for AGB, stable for BGB, and negative for the BGB:AGB ratio, which highlights the crucial role of higher species richness in ecosystem functioning. Significant differences in mean species richness among sites (9–19 species in meadow steppe and 8–22 species in alpine meadow) highlight the varying levels of species diversity across sites in the QTP. While 42% of the sites showed stable species richness, the reported increasing trends in species richness at 58% of the sites indicate the potential for ecological changes or processes in these areas. AGB in both grasslands increased, while BGB remained stable with increasing precipitation. The top soil layer (0–10 cm) dominated the observed BGB in both grasslands, as abundant nutrients in the top layer provide favorable conditions for root proliferation. In meadow steppe, AGB formed an isometric relationship with BGB, indicating that AGB increased with BGB. This study concludes that species richness influenced ecosystem functioning, and forbs and grasses dominated biomass productivity, of which the topsoil layer contributed three-quarters of BGB. Our study (i) provides empirical evidence of stable to increasing species richness in both grasslands over 5 years, and (ii) highlights the role of greater species richness in enhancing ecosystem functioning. These findings serve as a scientific reference for policymaking regarding ecosystem stability.

Transcriptome and anatomical analysis of Stipa breviflora in response to different grazing intensities in desert steppe.

Stipa breviflora is a dominant species in the desert steppe of Northern China. Grazing is the main land use pattern of grassland, which could cause a variety of adaptive evolutionary mechanisms in plant community composition as well as individual plant growth and morphological characteristics. However, very little is known about the morphological structure and transcriptional regulation response to different grazing intensities in S. breviflora. In this study, transcriptome and anatomical analyses of S. breviflora under different grazing intensities, including no grazing, moderate grazing, and heavy grazing, were performed. The anatomical analysis results showed that epidermis cells and xylems significantly thicken with grazing intensity, suggesting that grazing results in increasing lignification. Furthermore, the components of cell walls such as lignin, cellulose, hemicellulose, and pectin were all increased dramatically and significantly under both moderate and heavy grazing. Transcriptome analysis showed that the differentially expressed genes related to different grazing intensities were also engaged in plant cell wall formation and in photosynthesis and respiration. In addition, the activities of ATP synthase and Rubisco-activating enzyme increased significantly with enhanced grazing intensity and differed significantly between moderate and heavy grazing intensities. The trends in transcriptome and plant phenotype changes are consistent. Taken together, these results indicated that S. breviflora has evolved a grazing tolerance strategy under long-term grazing conditions, influencing photosynthesis and respiration in terms of its own structure and enzyme activities in the body, to maintain normal life activities under different grazing conditions.

Mild to moderate drought stress reinforces the role of functional microbiome in promoting growth of a dominant forage species (Neopallasia pectinata) in desert steppe.

Desert steppe ecosystems are prone to drought stress, which influences the ecological balance and sustainable development of grasslands. In addition to directly restrict plant growth, drought stress indirectly impacts plant fitness by altering the diversity and function of root-associated microbiomes. This begs the question of whether the functional microbiome of forage plants, represented by synthetic microbial communities (SynComs), can be leveraged to mitigate drought stress in desert steppes and promote the ecological restoration of these fragile ecosystems. A pot experiment was conducted to evaluate the role of SynComs in improving the plant growth and drought stress resistance of Neopallasia pectinata (Pall.) Poljak in desert steppe in Inner Mongolia, China. Six SynComs were derived from the rhizosphere and root endosphere of 12 dominant forage species in the desert steppe. Each SynCom comprised two to three bacterial genera (Bacillus, Protomicromonospora, and Streptomyces). We examined the capacities of different SynComs for nutrient solubilization, phytohormone secretion, and enzymatic activity. Under no water stress (75% soil water holding capacity, WHC), single strains performed better than SynComs in promoting plant growth in terms of stem diameter, root length, and plant dry weight, with the greatest effects observed for Streptomyces coeruleorubidus ATCC 13740 (p < 0.05). However, under mild to moderate drought stress (55% and 35% WHC), SynComs outperformed single strains in enhancing plant biomass accumulation and inducing the production of resistance-related substances (p < 0.05). No significant effect of single strains and SynComs emerged under extreme drought stress (20% WHC). This study underscores the potential of SynComs in facilitating forage plants to combat drought stress in desert steppe. Mild to moderate drought stress stimulates SynComs to benefit the growth of N. pectinata plants, despite a soil moisture threshold (21% WHC) exists for the microbial effect. The use of SynComs provides a promising strategy for the ecological restoration and sustainable utilization of desert steppes by manipulating the functional microbiome of forage plants.

Comparative venation costs of monocotyledon and dicotyledon species in the eastern Colorado steppe.

Leaf vein network cost (total vein surface area per leaf volume) for major veins and vascular bundles did not differ between monocot and dicot species in 21 species from the eastern Colorado steppe. Dicots possessed significantly larger minor vein networks than monocots. Across the tree of life, there is evidence that dendritic vascular transport networks are optimized, balancing maximum speed and integrity of resource delivery with minimal resource investment in transport and infrastructure. Monocot venation, however, is not dendritic, and remains parallel down to the smallest vein orders with no space-filling capillary networks. Given this departure from the "optimized" dendritic network, one would assume that monocots are operating at a significant energetic disadvantage. In this study, we investigate whether monocot venation networks bear significantly greater carbon/construction costs per leaf volume than co-occurring dicots in the same ecosystem, and if so, what physiological or ecological advantage the monocot life form possesses to compensate for this deficit. Given that venation networks could also be optimized for leaf mechanical support or provide herbivory defense, we measured the vascular system of both monocot and dicots at three scales to distinguish between leaf investment in mechanical support (macroscopic vein), total transport and capacitance (vascular bundle), or exclusively water transport (xylem) for both parallel and dendritic venation networks. We observed that vein network cost (total vein surface area per leaf volume) for major veins and vascular bundles was not significantly different between monocot species and dicot species. Dicots, however, possess significantly larger minor vein networks than monocots. The 19 species subjected to gas-exchange measurement in the field displayed a broad range of Amax and but demonstrated no significant relationships with any metric of vascular network size in major or minor vein classes. Given that monocots do not seem to display any leaf hydraulic disadvantage relative to dicots, it remains an important research question why parallel venation (truly parallel, down to the smallest vessels) has not arisen more than once in the history of plant evolution.

Relative contributions of taxonomic and functional diversity to the assembly of plant communities hosting endemic Dianthus species in a mountain steppe

Plant community assembly is the outcome of long-term evolutionary events (evident as taxonomic diversity; TD) and immediate adaptive fitness (functional diversity; FD); a balance expected to shift in favour of FD in ‘harsh’ habitats under intense selection pressures. We compared TD and FD responses along climatic and edaphic gradients for communities of two species (Dianthus pseudocrinitus and D. polylepis) endemic to the montane steppes of the Khorassan-Kopet Dagh floristic province, NE Iran. 75 plots at 15 sites were used to relate TD and FD to environmental gradients. In general, greater TD was associated with variation in soil factors (potassium, lime, organic matter contents), whereas FD was constrained by aridity (drought adaptation). Crucially, even plant communities hosting different subspecies of D. polylepis responded differently to aridity: D. polylepis subsp. binaludensis communities included a variety of broadly stress-tolerant taxa with no clear environmental response, but TD of D. polylepis subsp. polylepis communities was directly related to precipitation, with consistently low FD reflecting a few highly specialized stress-tolerators. Integrating taxonomic and functional diversity metrics is essential to understand the communities hosting even extremely closely related taxa, which respond idiosyncratically to climate and soil gradients.

Ecological significance of marcescence in Himalayan plants: Why is standing dead phytomass more important in demanding, resource‐limited environments?

Abstract Understanding mechanisms allowing plants to thrive in challenging conditions is critical for predicting their responses to global environmental change. An often overlooked ecological adaptation is marcescence, where leaves and stems are retained beyond their typical shedding time, with implications for nutrient recycling and carbon sequestration. Marcescence can be expected in plants with conservative resource‐use strategies, especially in environments with limited resources and marked seasonality, such as deserts and alpine regions. However, the extent to which marcescence occurs in different taxa across different habitats and its relationship to seasonality and plant functioning as reflected in ecophysiological traits remains understudied. We studied 600 individuals across 40 Himalayan herb species found in desert, steppe, alpine and subnival habitats, spanning 3000–5400 m elevation. Marcescence was observed in 37 of the 40 species evaluated, with 57% of the sampled individuals displaying dead phytomass, indicating the widespread nature of this phenomenon in Himalayan ecosystems. Environment and plant traits emerged as significant factors influencing the amount of dead‐standing biomass. These findings remained robust after accounting for intraspecific variation and phylogenetic inertia. Desert and steppe species exhibited greater marcescent biomass, characterized by 10‐fold more dead stem biomass than alpine and subnival plants. In contrast, the proportion of dead phytomass increased with elevation due to increased dead leaf fraction. Taller desert species with heavily lignified stems and limited nitrogen and phosphorus content had high levels of stem marcescence, which not only may aid litter photodegradation and nutrient recycling but also deter herbivory and promote seed dispersal (tumbleweed). Conversely, slow‐growing alpine and subnival plants with higher water‐use efficiency, foliar C:N ratios and parenchymatic storage tissue rich in mobile carbohydrates had a high proportion of marcescent leaves, which may aid survival in these resource‐limited environments by providing delayed nutrients through moisture‐conserving mulch that also provides insulation and protection from frost. This study provides new insights into the complex interplay of habitat, seasonality and plant traits in dead phytomass retention in Himalayan plants. Marcescence is prevalent in resource‐conservative species in highly seasonal, resource‐limited habitats and may significantly shape the functioning and biodiversity of Himalayan ecosystems. Read the free Plain Language Summary for this article on the Journal blog.

Expanding and invading plant species in sagebrush steppe affect multiple aspects of small‐mammal ecology

AbstractInvasion and expansion of non‐native and native plants have altered vegetation structure in many terrestrial ecosystems. Small mammals influence multiple ecosystem processes through their roles as ecosystem engineers, predators, and prey, and changes to vegetation structure can affect habitat use, community composition, and predator‐prey interactions for this assemblage of wildlife. In the sagebrush (Artemisia spp.) shrublands of the western United States, invasion by non‐native grasses and expansion of native conifer trees beyond their historical range has altered vegetation structure. These changes may potentially affect distributions and interactions of deer mice (Peromyscus maniculatus), which are generalist omnivores, and Columbia Plateau pocket mice (Perognathus parvus), more specialized granivores. To assess the extent to which altered habitat affects small‐mammal density, survival, and home‐range size, we examined these aspects of small‐mammal ecology along a gradient of cheatgrass (Bromus tectorum) invasion and western juniper (Juniperus occidentalis) establishment in sagebrush shrublands in southwestern Idaho, USA. From 2017–2019, we used a spatially explicit mark‐recapture design to examine attributes of small‐mammal ecology along an invasion gradient. We did not find support for an effect of cheatgrass cover on density or survival of either species. Home‐range size of deer mice was 2.3 times smaller in heavier cheatgrass cover (60%) compared to areas with little or no cheatgrass cover. Density of deer mice was highest (5 individuals/ha) in areas with 10% juniper cover and decreased with increasing juniper cover, whereas density of pocket mice was positively influenced by shrub cover. Survival of deer mice declined as juniper stem density increased. Conversely, survival of pocket mice increased with increasing juniper stem density. We found evidence for interspecific interactions between these 2 species, in the form of a density‐dependent effect of deer mice on pocket mouse home‐range size. Home‐range size for pocket mice was 2 times smaller in areas with the highest estimated density of deer mice compared to areas with low densities of deer mice. Our data provides unique information about how small mammals in the sagebrush steppe are affected by expanding and invasive plant species and potential ways that habitat restoration efforts, in the form of conifer removal, may influence small mammals. Understanding the response of small mammals to conifer expansion or removal may shed light on the demographic and numerical responses of other wildlife associated with the sagebrush biome, including predators.

Wild plant species with broader precipitation niches exhibit stronger host selection in rhizosphere microbiome assembly.

Plants actively recruit microbes from the soil, forming species-specific root microbiomes. However, their relationship with plant adaptations to temperature and precipitation remains unclear. Here we examined the host-selected and conserved microbiomes of 13 native plant species in the Xilingol steppe, Inner Mongolia, a semi-arid region in China. By calculating the global precipitation and temperature niches of these plants, considering plant phylogenetic distances, and analyzing functional traits, we found that these factors significantly influenced the rhizosphere microbiome assembly. We further quantified the strength of host selection and observed that plants with wider precipitation niches exhibited greater host selection strength in their rhizosphere microbiome assembly and higher rhizosphere bacterial diversity. In general, the rhizosphere microbiome showed a stronger link to plant precipitation niches than temperature niches. Haliangium exhibited consistent responsiveness to host characteristics. Our findings offer novel insights into host selection effects and the ecological determinants of wild plant rhizosphere microbiome assembly, with implications for steering root microbiomes of wild plants and understanding plant-microbiome evolution.

Континентальность климата и теплообеспеченность почв степных склонов в верховьях Индигирки и Колымы

Steppe biotopes on the southern slopes of the Indigirka and Kolyma headwaters, judging by vegetation and invertebrate population, are analogous to South Siberiaвs mountain steppes. At the same time, the area of steppe slopes and the number of steppe plant and animal species decrease from the Indigirka to the Kolyma. Climate continentality decreases in the same direction, which permits to consider it the main factor impacting the distribution of thermophytic steppes in Northeast Asia. Measurements of temperatures in thermophytic steppe soils in the named river basins revealed no soil heat supply differences related to climate continentality. Comparison of the measurement results with long-term observation data on xeromorphic biotopes of southern slopes in the upper reaches of the Kolyma River permitted to extend this conclusion to the soils of all open dry southern slopes in the headwaters of the Kolyma and Indigirka rivers. Thus, the role of climate continentality and summer soil temperature regime in the long-term preservation of "islands" with a large number steppe species of plant and animal surrounded by permafrost mountain-taiga ecosystems in the upper reaches of the Indigirca River is questioned. It is shown that restrictions in the spatial distribution of some steppe invertebrate species are not determined by differences in the summer temperature regime of soil in the headwaters of the Indigirka and Kolyma Rivers, either.

Floristic composition of sand massifs in the western part of the Sub Ural plateau

Currently, on the territory of Kazakhstan, one of the topical issues is the study of the current state of ecosystems. The aim of the study is a biomorphological, geographical and ecological analysis of thesand massifs flora inthe western part of the Sub Ural plateau. 137 species of vascular plants belonging to 99 genera and 35 families were registered in the Karagash and Akkum sand massifs. Most of the flora (70; 50.4%) is occupied by species belonging to the Asteraceae, Poaceae, Fabaceae and Chenopodiaceae families. The predominant in the flora are rhizomatous species: Calamagrostis epigeios, Carex colchica, Helichrysum arenarium, Leymus racemosus, Scirpoides holoschoenus, etc.The presence of adventitious species in the flora indicates high anthropogenic pressure, unfavorable growing conditions and habitat disturbance. The predominance of xerophytes is associated with the adaptation of psammophytesand steppe species to growing in arid climates. The chorological analysis showed the predominance of the wide-ranging Eurasian and Ancient Mediterranean species.There is a need to protect meadow and psammophytic mixed-grass-stipa grass and juniper communities. They belong to plant species distribution area of which is currently being intensively reduced, so it is necessary to organize comprehensive measures to protect their growing environment. Information about the species composition of plants, their biological and ecological features, which in the future will become the basis for the organization of monitoring work, are of great practical importance.