Open Access
Access granted
Subscription Access
No 4 (2023)
Articles
Stochastic and Deterministic Processes in the Establishment of Taxonomic, Functional and Phylogenetic Diversity of Ecological Communities: A Review of Modern Concepts
Abstract
The assessment of biological diversity and the processes that govern it is important for ecological research and nature conservation. This review describes the main general theories and presents the modern concept of mechanisms for the assembly of ecological communities. Deterministic (abiotic filter and biotic interactions) and stochastic (ecological drift, dispersal and speciation) processes influencing taxonomic, functional and phylogenetic facets of diversity are discussed. Impact of certain processes (influence of individual environmental factors, biotic interactions, dispersal limitation) on the - and - levels of each facet of biodiversity are shown. In turn, estimation of them makes it possible to assess the contribution of certain processes on the biodiversity of the studied local communities.
245-260
Invasion Levels of Alien Plants in Various Habitat Types in the Middle Urals
Abstract
The purpose of the study was to estimate invasion levels of alien plants in various natural and anthropogenic habitats of the Middle Urals in two urbanization manifestation variants: (1) within the boundaries of a large city; and (2) in suburban areas. In total, 965 geobotanical releves produced in natural (bogs, floodplains, petrophytic areas, meadows, and forests) and anthropogenic (wastelands, public gardens, and residential areas) habitats were analyzed. Natural habitats were surveyed within the boundaries of a large city and in its suburban zone (at distances of 30–40 km from the city). Invasion levels were determined based on the number and proportion of alien (adventitious) species in the description. Both in suburban and urban conditions, the lowest numbers of alien species were recorded in bog habitats (on average, 0–0.6 species per description); while the largest numbers, in anthropogenic habitats (on average, 9.8–17.6 species per description). Outside the city, average numbers of alien species in natural habitats (except for bogs) varied in the range of 1.0–2.8 species per description; within the city, 3.8–6.2 species per description. In natural habitats (except for bogs), average shares of alien species varied in the range of 1.8–5.6% outside the city and in the range of 8.1–16.2% within the city; in anthropogenic habitats, they varied in the range of 22.8–32.8%. Suburban and urban wastelands did not differ in numbers and proportions of alien species (10.3 and 12.9 species per description and 25.3 and 30.2%, respectively). Invasion levels identified in suburban areas are consistent with those recorded in Europe.
261-270
Effect Exercised by Climate on the Taxonomic Diversity of Vascular Plants in the Middle Volga Region
Abstract
Analysis of relationships between the richness of three taxonomic ranks of vascular plants in the Middle Volga region and climate showed that the climatic factor explains 74% of variance in the number of species and families and 76% of variance in the number of genera. Taxonomic parameters of a floristic sample collected on 25 polygons 100 km2 in size each were compared with climatic parameters and their functions. Multiple regression models were produced for the three taxonomic ranks (numbers of families, genera, and species), and maps have been constructed on the basis of these models. The main predictors were climatic parameters at the beginning of spring and in winter months. Statistically significant correlations between the richness of species, genera, and families and some functions of climatic parameters that are usually excluded from analysis were identified. The essence of these functions is discussed in the context of their effect on snow melting processes in early spring.
271-280
Over 50 Years of Overgrowth of the Ash Dump, The Content of Nitrogen and Phosphorus Changed in Young Soils but it Did Not Change in Plants
Abstract
Changes in the nitrogen (N) and phosphorus (P) content in the ash substrate and plant leaves during the primary succession of overgrowing ash dumps of different ages were studied. The work was carried out on the young (overgrowth duration 5–8 years) and old (overgrowth duration 53–56 years; two sites – with meadow and forest vegetation) ash dumps of a thermal power plant in the Middle Urals. In the emerging soil and leaves of model plants, the content of N and P was determined on each dump. In young soils, a predictable and explainable successional dynamics of N and P was established: over 53–56 years, the N content increased 2.4–7.1 times, while the P content decreased 1.1–2.1 times. In plant leaves, the content of N and P at different stages of overgrowth was actually constant: 1.6–2.1% of N and 2.2–2.9 mg/g of P. In general, it has been found that in successionally young habitats, and in more advanced ones with developing forest vegetation, against the background of a multiple increase in the N content in the soil, the N content in plants remains low. With a high probability, on both dumps, the availability of nitrogen is a factor limiting the development of plants. This is evidenced by the results of the analysis of N/P ratio values in leaves and comparison of our array of N values in leaves with global averages of N content in the same species. Thus, the results with respect to the successional dynamics of the content of nitrogen and phosphorus in soils and plants of dumps of different ages turned out to be surprisingly little consistent with each other.
281-290
Soil Nematodes of Northern Meadows and Agrocoenoses as Bioindicators of the Transformation Degree in Soil Ecosystems
Abstract
This paper examines the effect exercised by agricultural intensity on soil nematode communities inhabiting natural meadows, hayfields, and monocrop agrocoenoses in the Republic of Karelia. The diversity of the soil nematode fauna in natural meadows is similar to that in hayfields, but it significantly decreases in agrocoenoses. The abundance of nematodes reaches the highest values in soils of meadows and decreases as land use intensity goes up. Bacterial feeders predominate in the eco-trophic structure of nematode communities in all types of biocoenoses reaching the maximum share in agrocoenoses. The relative abundance of predators and nematodes associated with plants in agrocoenoses is significantly lower compared to natural meadows and hayfields. Ecological indices computed for nematode communities indicate the presence of a stable and multicomponent soil ecosystem in meadows. The CI index reflecting the predominant pathway of organic matter decomposition indicates an active participation of bacteria in the destruction. Values of the SI and CI indices decrease in agrocoenoses, while the EI index increases. Such a ratio between indices specifies simplified food web and a disturbed soil ecosystem in agrocoenoses. Discriminant analysis shows that, of all studied biocoenoses, only agrocoenoses and natural meadows can be differentiated statistically significantly based on differences in the SI index. However, the identified positive effect of latitude on the SI index in agrocoenoses indicates that the application of this parameter to northern ecosystems has some limitations.
291-301
Influence of the Invasive Earthworm Eisenia nana (Lumbricidae) on the Content of Water-Soluble Forms of Cations (NH4+, K+, Na+, Mg2+, Ca2+) in Soil
Abstract
Using a field simulation experiment in mesocosms, the influence of epi-endogeic earthworms was assessed, invasive E. nana and native E. nordenskioldi (in monopopulations and when kept together), on the availability of cations (NH4+, K+, Na+, Mg2+, Ca2+) in soil. A significant effect of both species on the increase in the content of sodium ions in the 10–15 cm soil layer relative to the control without worms, differences between the E. nana and E. nordenskioldi monovariants in the content of magnesium and calcium ions in the 0–5 cm layer, and a significant effect of the interaction of species on an increase in the availability of ammonium in the 20–30 cm layer.
302-310
Distribution of Trophic Resources in a Rodent Community in the High-Mountain Zone of the Republic of Dagestan
Abstract
Quantitative and qualitative characteristics of nutrition of some cohabiting rodent species in the High-Mountain Zone of the Republic of Dagestan have been studied. The diet of S. uralensis consisted of 23, C. gud, of 22, M. arvalis, of 27, C. migtatorius, of 26, and D. nitedula, of 19 plant species. The most diverse diet was found in the common vole and gray hamster. In spring, sedges dominated in the diets of rodents, in the summer, rations consisted mainly of cereals, and autumn, predominantly from the species of the forbs and legume groups. In all, except for the forest dormouse, the conjugation of diets with the structure of herbaceous vegetation was revealed. The maximum values of the degree of similarity of the diets of rodents were found in pairs of wood mouse – Gudaur vole, Gudaur vole – gray hamster, and common vole – gray hamster. As a result, a sufficient level of food supply, a wide range of microstations, and intrapopulation adaptation mechanisms make it possible for the considered rodent species to live together in the study area.
311-317
КРАТКИЕ СООБЩЕНИЯ
318-322