Dynamics of floristic composition of communities dominated by Carex acuta in the northern Volga-Akhtuba floodplain

The floristic composition of plant communities dominated by Carex acuta in the northern Volga-Akhtuba floodplain has been analyzed over the period from 1928 to 2009. It has been shown that, in 2008 to 2009, some hygrophytes disappeared from these phytocenoses; simultaneously, their composition was enriched with mesophytes and adventive species. Ramenskii??s ecological scales have indicated a decrease in water supply to habitats of the communities studied.     

Assessment of the ecological risk of technogenic soil pollution on the basis of the statistical distribution of the occurrence of micromycete species

A methodology of substantiating the ecological risk of technogenic soil pollution has been described according to the results of bioindication using microfungal communities. At the first state, the values of the factors under which the frequency of each species is maximal were estimated using ordination methods. The statistical distribution of the species sensitivity was simulated according to these data. The methodology was illustrated using the results of analysis of the toxicity of soil samples from uranium mine dumps (the village of Kadzhi-Sai, Kyrgyzstan). The preliminary estimates of the critical values of six soil pollution indices that provide the defined allowable probability of the ecological risk have been given.     

Macrozoobenthos as an indicator of the ecological state of mountain watercourses

Structural characteristics of benthic macroinvertebrate communities in mountain watercourses of different sizes have been studied in the Upper Ob basin. It has been found that species richness, diversity of zoobenthos, and most biotic indices in the background areas increase in the series from the smallest watercourses to large rivers. On the contrary, the values of the above parameters in areas polluted with mercury has proved to decrease, thereby indicating a significant transformation of the benthic communities. Approaches are proposed to select reference indices for assessing the ecological state of watercourses in the basin with regard to the size of the river, the structure of benthic communities, and variability of biotic indices along the background cross sections.     

Plant communities in the zone of gas field development and heavy metal accumulation by them

Heavy metal accumulation by plant communities has been studied in different zones of impact of gas field development. The contents of heavy metals in different blocks of plant communities has proved to depend not only on the location of phytocenosis but also on its species composition. Communities dominated by species of the family Poaceae contain smaller amounts of heavy metals than those dominated by species of the family Asteraceae, especially of the genus Artemisia. The order of precedence in the accumulation of heavy metals in different blocks of plant communities has been revealed.     

Typological and species diversity of dark conifer forests in the lower reaches of the Bol’shaya Porozhnyaya River, a tributary of the Pechora (Pechora-Ilych state nature reserve)

The structure of dark conifer forests in the lower reaches of the Bol’shaya Porozhnyaya River is described. Ordination of corresponding communities has been performed, and their ecological and ecocenotic characteristics and species structure have been analyzed. On this basis, a typological scheme of the forests has been constructed following the method by L.B. Zaugol’nova. The identified sections and variants of communities within the true moss and tall herb sections are described. Successive change of leading ecological factors in the hierarchical series of communities, from sections to variants, is demonstrated.     

Spatial population structure of rare orchid species in rich fens in the central part of Murmansk oblast

The spatial structure of 10 populations of rare orchid species (Dactylorhiza incarnata, D. traunsteineri, Listera ovata) has been studied in rich fens sporadically occurring in Murmansk oblast. Two levels of plant aggregation within populations have been distinguished: (1) clusters of individuals and (2) isolated population subsets consisting of clusters. General spatial demographic features of orchid populations in the fens are small area (77 m²) and low ecological density (0.009 ind./m²). Characteristics of the population subsets (their number, area, composition, and distance to the neighboring subset) are species-specific and reflect the degree of species rarity in plant communities.     

Specific features of zooplankton community in industrially polluted areas of Subarctic Lake Imandra (Monche, Belaya, and Molochnaya Bays)

Specific structural features of the zooplankton community of Lake Imandra have been analyzed in areas polluted with wastewaters from the copper-nickel industry (Monche Bay) and apatite-nepheline industry (Belaya Bay) or heated waters from the Kola Nuclear Power Plant (Molochnaya Bay) and in a conditionally clean (background) area (the eastern and western parts of Babinskaya Imandra pool). The current ecological state of these communities has been assessed. The results contribute to knowledge about the responses of hydrobionts to pollution with different kinds of industrial wastewaters and the potential of using the zooplankton community as a reliable indicator for evaluating the state of aquatic ecosystems.     

Is there a density compensation effect in plant communities of anthropogenic habitats?

The occurrence of density compensation effect (DCE) has been estimated in areas occupied by synanthropic communities in the Western Caucasus. The density of dominant plant species has been estimated from their coverage, and that of subordinate species, from their frequency in 0.5-m² squares within 15 (16)-m² plots, using natural and seminatural communities as a reference standard. The factual material has been analyzed by the method of numerical experiments. The results show that the transformation of natural habitats into anthropogenic ones has led to a decrease in the species diversity of plant communities, but without causing a widespread occurrence of DCE. It is hypothesized that relatively high average values of species frequency in low-diversity synanthropic communities are more likely accounted for by random rather than compensatory processes.     

Expansion of invasive alien plant species in the republic of Bashkortostan, the Southern Urals: Analysis of causes and ecological consequences

The causes and ecological consequences of alien plant species invasions in the Southern Urals are analyzed. Aggressive invasive species of North American origin??Ambrosia trifida L., A. psylostachya DC., Cyclachaena xanthiifolia (Nutt.) Fresen., Hordeum jubatum L., Oenothera biennis L., Bidens frondosa L., etc.??have invaded synanthropic and natural plant communities and became dominant, with their proportion varying from 10 to 99%. The biomass of these plants may reach 6 kg/m²; density, more than 1000 shoots per square meter; and seed production, up to 30000 seeds per plant, which explains their dominance in communities. The ecological hazard they pose lies in the displacement of native species, overgrowing of disturbed land areas, and allergenicity of their pollen.     

Flora biodiversity change detection: a case study

Changes in flora biodiversity are a dilemma facing managers in order to cope with challenges of extinction or endangering plant species as well as replacement by invasive species. Such problems can occur in the region as disruption of ecosystem balance. The first step of proper management of a watershed is obtaining accurate information about plant communities and their dominance and biodiversity status. Such information will help decision makers to adopt an appropriate management approach. Accordingly, the current study was conducted to detect various types of plant species in Zanjanrood Watershed. For this porous, quadrate and transect methods were applied to determine available plant species in the region. Afterwards, Shannon and Simpson’s Reciprocal indices were used to specify the biodiversity status of the identified communities. The calculation results revealed 3.19 and 5.98 for Shannon and Simpson’s Reciprocal indices, respectively. As the results suggested, there has been a downward trend in biodiversity status over the last 20 years. Such a deteriorating condition has been accelerated rise in recent years so that the non-palatable species are rapidly replaced by the palatable ones due to uncontrolled overgrazing of livestock. If management is not based on principles of sustainability in the region, the watershed will experience an extreme poverty of land cover. The findings would be so helpful to achieve an appropriate strategy in order to conserve the biodiversity in a sustainable manner.     

Ecological structure of plant communities on spring fens in the mountain taiga belt of the Southern Urals

Based on gradient analysis and indicator values, spring water chemistry and temperature and the dynamics of water level were shown to be the main ecological factors of plant cover differentiation in spring fens. Six groups of plant communities were identified by ordination along the axes of these factors, with each group being characterized by a certain suite of indicator species.     

Saturation and invasion resistance of non-interactive plant communities

Open plant assemblages in shoals of western Caucasian rivers were used as examples to analyze the relationship between the species saturation and the number and total abundance of alien species in non-interactive communities. Invasion of exotic species into highly saturated communities has been demonstrated to be, on average, less probable than their invasion into unsaturated communities. A hypothesis explaining the relationship between these parameters has been put forward. According to the hypothesis, the number of alien species in a specific locality in a community is determined by their ratio to the number of native species in the species pools of these communities; and their mean abundance, by the ratio of the total number of species to the number of individuals in the localities. Both ratios are smaller in saturated biocenoses, which determines a relatively small admixture of alien species in them.     

Effect of ecotopic factors and nature resource use on the diversity of forest communities in northern Kostroma oblast

The results of studies on southern taiga forests in northern Kostroma oblast are presented. They include the typing of old-growth forests, their phytocenotic and ecological characterization, and assessment of their structural and species diversity, successional status, and degree of anthropogenic disturbance. Geomorphological features of the study area and parameters of soils under plant communities of different forest type groups are described. On the basis of generalization of available data, conclusions were drawn concerning specific features of the structure and species diversity of forest communities in different ecotopes and at different stages of succession.     

Evolutionary ecological analysis of coupled geographic variation of two sympatric rodent species in the Southern Urals

Geometric morphometrics has been used to reveal coupled geographic variation in the mandible shape in two sympatric rodent species, the pygmy wood mouse (Sylvaemus uralensis Pall.) and bank vole (Myodes glareolus Pall.), in the Southern Urals. It has been shown that syntopic samples synchronously collected from the local communities of these species usually display similar, parallel, and unidirectional morphological changes as demonstrated by comparison of species pairs from different localities. The degree of concordance in geographic variation of the species makes it possible to estimate their coevolutionary potential within local communities: the wider the range of ecological conditions under which parallel variation of sympatric species is observed, the higher is their coevolutionary potential.     

Analysis of Catenae in the Kivach Reserve: Structure,Succession State,and Potential Composition of Forest Vegetation

Types of catenae of the moraine landscape of the Kivach Reserve have been described, and five ecotopes have been distinguished in their composition. The analysis of ecological ranges of the main forest-forming species has made it possible to predict the potential composition of a tree synusia that included five to seven species in the greater part of the catenae and three species in depressions with stagnant moistening. The population demographic approach has been used to determine the succession status of communities in the study area. Six variants of phytochores have been distinguished in the herb-dwarf shrub layer; the main ecological and succession factors of distribution have been determined for them.__________Translated from Ekologiya, No. 4, 2005, pp. 252–258.Original Russian Text Copyright © 2005 by Platonova.     

Distribution of plants differing in attitude toward thermal conditions in communities of the timberline ecotone on Mount Iremel’, the Southern Urals

Specific features in the distribution of plant species differing in their attitude toward thermal conditions have been studied in communities of the present-day timberline ecotone on Mount Iremel’ in the Southern Urals. It has been shown that the distribution of such species is characterized by significant spatial nonuniformity. Elevation above sea level, local conditions in habitats located at the same altitudinal level, and specific features of mountain slopes account for 13–84, 5–30, and 0.4–14% of the total variance of test parameters, respectively. The abundance of plants changes nonlinearly along the altitudinal gradient, whereas changes in the species diversity of different plant groups have an almost linear pattern. Marked differences between plant communities with respect to the proportions of species differently responding to changes in thermal conditions have been revealed on all slopes in the upper part of the timberline ecotone, upon transition from the slopes proper to the plateau-like areas of intermontane depressions.     

The State of Protected Forest Communities in the European Forest–Steppe Zone of Russia and Prospects for Their Reconstruction: A Case Study of Specially Protected Areas of Penza Oblast

The structure of most forest communities in the European forest–steppe, including protected areas, has been disturbed. The adverse consequences of these disturbances include the incomplete age structure of the populations of cenosis-forming species and the irreversibility of successions. The conservation of biodiversity in the structurally disturbed communities is impossible without human intervention, which must be aimed at restoring their age heterogeneity with regard to their specific ecological features.     

Effect of heavy metal pollution on plant communities of the Tanalyk River,the Bashkir Transural region

Geobotanical analysis of aquatic and wetland plant communities of the Tanalyk River has been performed in the zone of impact from the abandoned Kul-Yurt-Tau pyrite mine. The results show that pollution of the river with highly mineralized runoff leads to a decrease in the β-diversity and synthetic characteristics of plant communities (α-diversity, total coverage, and herb layer height) and in the aboveground phytomass of dominant species.     

The Relationship of Dominance and Evenness with Productivity and Species Richness in Plant Communities with Different Organization Models

The relationship between dominance and evenness in plant communities organized according to different models—competitive (alpine, subalpine, and low-mountain grasslands), stress-tolerant (alpine heaths and scrubs, subalpine fens, steppes, the forest herbaceous layer), and ruderal—has been analyzed in the Western Caucasus and Ciscaucasia. No correlation between evenness (dominance) and productivity has been revealed in communities of any type. The correlation between dominance and species richness is negative and, in most cases, linear, being stronger in competitive and ruderal than in stress-tolerant cenoses. The correlation between evenness and species richness in grassland communities (the competitive model) is strong, positive, and linear, while this correlation in ruderal and stress-tolerant communities is weak or absent.     

Current state of mountain steppes in Sverdlovsk oblast

The current state and phytodiversity of mountain steppes in Sverdlovsk oblast have been evaluated, involving an inventory of several botanical and botanical-geomorphological natural landmarks in the steppe landscape. New growth localities of rare plant species have been discovered. Scientific and natureconservation significance of the surveyed mountain steppe areas has been demonstrated. A set of informative indices has been used to identify the key protection sites of steppe vegetation. Four sites are recommended for inclusion in the system of specially protected areas with the status of natural landmarks.