Species Composition Of Plant Communities Research Articles

Drivers of Spontaneous Plant Communities in Urban Parks: A Case from Nanjing, China

Urban plant diversity is one of the key elements for sustainable urban development. Urban plant landscapes not only create a variety of experiences for residents but also have a positive effect on their physiology and psychology. In order to better introduce nature into urban green spaces, this study conducted a field survey in Nanjing, China, to analyze the current situation of spontaneous plants in Nanjing’s urban green spaces and propose a plant planning strategy that takes into account both ecology and residents’ well-being. This study surveyed the herbaceous plant resources in 96 sample plots in nine typical urban parks in Nanjing, and recorded 284 plant species in 192 genera and 78 families. The research results show that the differences in plant diversity, richness, and evenness among urban parks in Nanjing are significant; combined with cluster analysis and ranking results, the total area of urban parks, green space construction time, lighting conditions, and management frequency have an impact on plant communities. Further analysis of the species composition of plant communities showed that moderate management frequency in urban parks can increase plant diversity. With the advantages of both high ecological benefits and low management costs, a model of “artificial plants + native spontaneous plants” was finally proposed for the planting of herbaceous plants in sustainable urban green spaces.

Losses of low-germinating, slow-growing species prevent grassland composition recovery from nutrient amendment.

Nutrient enrichment often alters the biomass and species composition of plant communities, but the extent to which these changes are reversible after the cessation of nutrient addition is not well-understood. Our 22-year experiment (15 years for nutrient addition and 7 years for recovery), conducted in an alpine meadow, showed that soil nitrogen concentration and pH recovered rapidly after cessation of nutrient addition. However, this was not accompanied by a full recovery of plant community composition. An incomplete recovery in plant diversity and a directional shift in species composition from grass dominance to forb dominance were observed 7 years after the nutrient addition ended. Strikingy, the historically dominant sedges with low germination rate and slow growth rate and nitrogen-fixing legumes with low germination rate were unable to re-establish after nutrient addition ceased. By contrast, rapid recovery of aboveground biomass was observed after nutrient cessation as the increase in forb biomass only partially compensated for the decline in grass biomass. These results indicate that anthropogenic nutrient input can have long-lasting effects on the structure, but not the soil chemistry and plant biomass, of grassland communities, and that the recovery of soil chemical properties and plant biomass does not necessarily guarantee the restoration of plant community structure. These findings have important implications for the management and recovery of grassland communities, many of which are experiencing alterations in resource input.

Plant Allelopathy and Their Application in Gardens

The study of plant allelopathy is of extremely important research significance in agricultural and forestry production and management, as well as in ecological gardening applications in nature. Allopathies affects species composition in plant communities, It is one of the important factors affecting plant community succession. It is one of the important factors affecting plant community succession. In the application of garden landscape, the interaction and mutual restraint of communities are directly related to the final landscape effect. Therefore, by studying the effects of plants and garden applications, it is expected to provide reference value for garden landscape designers in the matching of garden landscape plants.

GROWING CONDITIONS AND SEED PRODUCTIVITY OF <i>PINGUICULA VULGARIS</i> (LENTIBULARIACEAE) IN LENINGRAD REGION

The growing conditions of Pinguicula vulgaris in the vicinity of the villages Pudost’ (floodplain meadow) and Glyadino (slope meadow, lowland spring fen) in the Leningrad Region were studied in detail, and the seed productivity of its plants was evaluated in these conditions for the first time. Despite a close geographical location and a general confinedness of both populations to the Izhora Upland (to the outcrops of carbonate rocks), they differ in an occupied area and its microtopography, the degree of shading of plants during daylight, and soil moisture (though of similar acidity), and also differ in the species composition of plant communities (richer in Pudost’ than in Glyadino). At the same time, regardless of the differences in growing conditions, the level of seed-setting in P. vulgaris plants in both populations during all the years of research was close and quite high (64–80% in Pudost’, 70–72% in Glyadino), that indicates a high potential for the renewal of the species in the populations by seed propagation. It is noted that the main factors limiting the size of Pinguicula populations in the Leningrad Region are the same as in its other populations of Northern Europe: intense settlement of territories by the species forming a layer with high closeness and height, trampling of soils, unfavorable weather conditions during flowering and fruiting of the plants significantly reducing their seed productivity. However, unlike some subarctic populations of P. vulgaris, where a decrease of seed productivity occurs due to low temperatures at the end of a short growing season and irregular reproduction (especially at the species moving into mountain conditions), in populations of the Leningrad Region (with a longer growing season and regular reproduction), it decreased mainly due to a long dry periods during flowering and fruiting of the plants.

Effects of Planting Density of Poaceae Species on Slope Community Characteristics and Artificial Soil Nutrients in High-Altitude Areas

Ecological restoration of slopes in high-altitude areas is usually difficult. Gramineae species are widely used in slope vegetation restoration due to their strong adaptability and rapid growth. In the process of ecological slope protection, increasing the seeding rate of gramineous species usually improves the success rate of slope vegetation restoration, but the long-term effect is not obvious. Therefore, choosing an appropriate planting density of grass species is beneficial to the sustainable restoration of slopes in high-altitude areas. This study evaluated the effects of different planting densities of Poaceae species on community characteristics and artificial soil nutrients on high-altitude slopes. The slope ecological protection engineering experiment was carried out in Jiuzhaigou County, Sichuan Province. Commercial seed mixtures of five grasses and legumes were sown at three different planting densities of Poaceae species (10, 5, and 1 g/m2). Plant community species composition, community diversity index, and soil-available nutrients were determined annually. The results showed that there were differences in the species composition of the slope plant community under different planting densities. There was a significant negative logarithmic correlation between the community diversity indices and the planting density of grass species, and it changed with the recovery time. There were significant differences in hydrolyzed nitrogen, available phosphorus and available potassium in artificial soil, and they decreased with a logarithmic function of the recovery time. There was a positive correlation between the community diversity indices and the soil nutrient content. Overall, our study shows that low planting densities of Poaceae species are beneficial to the long-term stability of ecological restoration when ecological slope protection works are performed on slopes in high-altitude areas.

Alien plant colonisation and community homogenisation: cause or consequence? A test in coastal dunes

Evidence of the effects of alien plant colonisation on plant communities is often hindered by the fact that similar patterns in community composition can arise through a variety of processes. The objective of this study is to determine whether changes in species composition in coastal dune communities depend on the colonisation of a neophyte plant, Oenothera stucchii, or on concurrent processes that favour its colonisation. We hypothesised two scenarios: 1) a direct impact of O. stucchii on colonised communities, leading to displacement of native species; or 2) no direct impact of O. stucchii, i.e. the species colonises plant communities by exploiting disturbances that lead to the rearrangement of plant communities. We used the species-habitat network approach to identify potential drivers of changes in species composition, assuming that changes in the structure of the species-habitat network depend on the nature of the driving process. We demonstrated that changes in species composition in plant communities were due to species rearrangement, with colonised communities characterised by more homogeneous composition of species. We suggest that changes in plant communities may not depend on colonisation by O. stucchii per se, but on concomitant processes that affect coastal dune communities while promoting colonisation by O. stucchii.

Formation of phytocoenotypes in soils of different degree of erosion

The paper focuses on issues related to problems of eroded soils and subsequent processes of development of serial communities aimed at formation of a stable climax phytocoenosis. A series is considered as a set of species that briefly inhabit a given territory replacing each other. Soil erosion development is caused by anthropogenic and natural factors; hence, this process is of a mixed natural-anthropogenic type. Soil erosion on slopes with elemental landscapes of any exposure affects the environmental conditions for the formation of phytocoenotypes and species composition of plant communities due to secondary successions and variation in dominants and subdominants. In this case, plant communities of herbaceous phytocoenoses of eroded soils exhibit both sequential and rapid changes in species composition with the appearance of species adapted to decreased soil fertility. The orientation, rate and number of successional changes depend on the intensity of erosion development. Severely eroded soils significantly increase the heterogeneity of the soil environment, creating optimal conditions for introduction of species that are often nontypical of the considered phytocoenoses; the number of assectators therefore increases in soils of this type. In case weakly eroded soils are used as the control, the number of assectators in severely eroded soils increases two to three fold, with possible fluctuation changes aimed at reducing assectators due to ecotopic and phytocoenobiotic selections.

The concept of noospheric ecosystems as the theoretical basis for monitoring studies of roadside landscapes

The purpose of the article. Considering the growing expansion of man in relation to nature, we should include the support (or violation) of the biosphere’s ability to self-reproduction as one of the most important criteria in all classifications and typologies of landscapes, ecosystems, geosystems, types of human activity. The main material. We implement this general criterion at the level of ecosystems of different species and spatial levels. Thus, we theoretically approach to the selection of anthropogenic landscapes (including linear ones), considering the priorities of ecosystem dynamics. The problem indicated in the title is primarily the result of constant density growth of the transport network, and, therefore, the ever-increasing “theft” of natural ecosystems by humans from aboriginal plants and animals. The main feature of the study in highly developed countries is the priority of preserving ecosystem dynamics during the construction and operation of highways. The solution to this problem, for example, in the USA today, is in the development of a practical guide for companies engaged in road construction. Based on such priorities, we should pay attention to the following quantitative and qualitative parameters of road landscapes that can affect the dynamics of infra-ecosystems: the species composition of plant communities, which can be an indicator of individual impacts of roads. For example, the presence of halophyte plants will help to fight against icing with salts or insufficient soil washing regime. The presence of invasive plants affects the intensity of the transfer of their seeds by vehicles or birds; the presence of hydrophyte plants, which may indicate insufficient drainage of the road surface, etc. External manifestations of the vital activity of animals on the roadside territories can help to assess the completeness of ecosystem relations in infra-ecosystems, signs of disruption of ecosystem dynamics by the road surface. In our opinion, the concept of noospheric ecosystems, of which infra-ecosystems (or road) are a part, can satisfy the indicated requirements for the highway monitoring research program. Road landscapes are an integral part of the transport infrastructure, from which the name “infra-ecosystem” actually originates. However, we consider natural (natural, natural-anthropogenic) processes in landscape-engineering and landscape-technogenic systems that are fully controlled by humans, as common features that determine road landscapes. They are extremely important for our research, as these systems are not capable of independent development, but manifest it only in their individual components. For example, artificially planted shrubs, trees, or sown grasses along the road surface are supplemented with plants characteristic of this natural zone over time, forming even certain plant groups. Conclusions. Monitoring research programs should answer the following main questions: How do the infraecosystems differ from the natural ecosystems of the area? In particular, assessment of all (or some types of impact): soil composition, hydrological regime, phyto- and zoo diversity, dustiness, noise pollution, radiation background, etc. How has this infraecosystem adapted to the conditions of anthropogenic impact (changes in the species composition of plants and animals, the formation of new trophic relationships, etc.)? What needs to be done to minimize the negative impact of transport activities on the new ecosystem, environmentally adapted infrastructure.

Intraspecific trait variability is a key feature underlying high Arctic plant community resistance to climate warming

AbstractIn the high Arctic, plant community species composition generally responds slowly to climate warming, whereas less is known about the community functional trait responses and consequences for ecosystem functioning. The slow species turnover and large distribution ranges of many Arctic plant species suggest a significant role of intraspecific trait variability in functional responses to climate change. Here we compare taxonomic and functional community compositional responses to a long‐term (17‐year) warming experiment in Svalbard, Norway, replicated across three major high Arctic habitats shaped by topography and contrasting snow regimes. We observed taxonomic compositional changes in all plant communities over time. Still, responses to experimental warming were minor and most pronounced in the drier habitats with relatively early snowmelt timing and long growing seasons (Cassiope and Dryas heaths). The habitats were clearly separated in functional trait space, defined by 12 size‐ and leaf economics‐related traits, primarily due to interspecific trait variation. Functional traits also responded to experimental warming, most prominently in the Dryas heath and mostly due to intraspecific trait variation. Leaf area and mass increased and leaf δ15N decreased in response to the warming treatment. Intraspecific trait variability ranged between 30% and 71% of the total trait variation, reflecting the functional resilience of those communities, dominated by long‐lived plants, due to either phenotypic plasticity or genotypic variation, which most likely underlies the observed resistance of high Arctic vegetation to climate warming. We further explored the consequences of trait variability for ecosystem functioning by measuring peak season CO2 fluxes. Together, environmental, taxonomic, and functional trait variables explained a large proportion of the variation in net ecosystem exchange (NEE), which increased when intraspecific trait variation was accounted for. In contrast, even though ecosystem respiration and gross ecosystem production both increased in response to warming across habitats, they were mainly driven by the direct kinetic impacts of temperature on plant physiology and biochemical processes. Our study shows that long‐term experimental warming has a modest but significant effect on plant community functional trait composition and suggests that intraspecific trait variability is a key feature underlying high Arctic ecosystem resistance to climate warming.

Soil heterogeneity in the horizontal distribution of microplastics influences productivity and species composition of plant communities.

Contamination of soils by microplastics can have profound ecological impacts on terrestrial ecosystems and has received increasing attention. However, few studies have considered the impacts of soil microplastics on plant communities and none has tested the impacts of spatial heterogeneity in the horizontal distribution of microplastics in the soil on plant communities. We grew experimental plant communities in soils with either a homogeneous or a heterogeneous distribution of each of six common microplastics, i.e., polystyrene foam (EPS), polyethylene fiber (PET), polyethylene bead (HDPE), polypropylene fiber (PP), polylactic bead (PLA) and polyamide bead (PA6). The heterogeneous treatment consisted of two soil patches without microplastics and two with a higher (0.2%) concentration of microplastics, and the homogeneous treatment consisted of four patches all with a lower (0.1%) concentration of microplastics. Thus, the total amounts of microplastics in the soils were exactly the same in the two treatments. Total and root biomass of the plant communities were significantly higher in the homogeneous than in the heterogeneous treatment when the microplastic was PET and PP, smaller when it was PLA, but not different when it was EPS, HDPE or PA6. In the heterogeneous treatment, total and root biomass were significantly smaller in the patches with than without microplastics when the microplastic was EPS, but greater when the microplastic was PET or PP. Additionally, in the heterogeneous treatment, root biomass was significantly smaller in the patches with than without microplastics when the microplastic was HDPE, and shoot biomass was also significantly smaller when the microplastic was EPS or PET. The heterogeneous distribution of EPS in the soil significantly decreased community evenness, but the heterogeneous distribution of PET increased it. We conclude that soil heterogeneity in the horizontal distribution of microplastics can influence productivity and species composition of plant communities, but such an effect varies depending on microplastic chemical composition (types) and morphology (shapes).

Differential responses of the seed germination of three functional groups to low temperature and darkness in a typical steppe, Northern China.

Seed germination is a key stage in the life history of plants, which has a crucial effect on plant community structure. Climate change has substantially altered the surface soil temperature and light availability, which can affect seed germination. However, whether the seed germination of different functional groups is affected by the interactions of light and temperature remains unclear. Under laboratory conditions, we examined the effects of low temperature and darkness, as well as their interaction, on the seed germination of 16 species belonging to three plant functional groups (annual and biennials, perennial grasses, and perennial forbs) in a typical steppe, Northern China. We found that low temperature had a significant negative effect on seed germination of all species. Low temperature significantly decreased the final germination percentage and germinative force of the three plant functional groups, and the germination duration of perennial grasses. Darkness significantly decreased the germinative force of perennial forbs and total seeds, and the germination duration of perennial grasses. The interactive effects of light and temperature on the seed final germination percentage and germinative force of perennial grass indicated that darkness strengthened the inhibitory effect of low temperature on the seed germination of the grass functional group. Our study indicate that the seed germination of different plant functional groups varied greatly in response to changing environmental conditions. Our results suggest that future climate change could alter the regeneration and species composition of plant communities through changing seed germination.

On the early warning signal of degradation in drylands: Patches or plants?

Abstract Global drylands are threatened by grazing pressure intensification and climate change, which act as major drivers of land degradation. Detecting this process at an early stage is essential for predicting losses of ecological functions and for restoration management. Vegetation patch‐size distribution is an indicator of dryland multifunctionality and has been proposed as a warning signal for the onset of degradation processes. However, we proposed and tested a general model that stresses that patchiness may fail to detect degradation of the forage provision, depending on plant community species composition. This is a key aspect since forage provision is strongly associated with human well‐being in drylands. We hypothesized that grazing‐induced changes in patchiness and forage provision converge in drylands dominated by forage species but are decoupled in those dominated or co‐dominated by non‐forage species. We tested the conceptual model in a unique regional‐scale gradient with strong ecological differences but a common biogeographical and human impact history to reduce local contingencies effects. We compared datasets of grazing intensification impacts on (i) plant cover and patch‐size distribution and (ii) plant density and plant‐size distribution of dominant forage grasses (a proxy of forage provisioning). We showed that there is a decoupling between grazing‐induced changes in vegetation patchiness and forage provisioning, particularly in drylands where non‐forage species are dominant. In these drylands, plant cover and patch‐size distribution were slightly affected by grazing intensification, whereas plant density of forage species was decimated and their plant‐size distributions were strongly skewed towards small sizes. Synthesis. Our dryland conceptual model suggests that global change impacts on forage species populations can be detected even before changes in patch‐size distribution and plant cover. Our findings support the model and indicate that the population status (plant density and plant‐size distribution) of forage species allows for predicting forage dynamics and is useful to the early detection of losses of ecosystem services linked to human well‐being in drylands.

Managing Fire-Adapted Invasive Plants in the American West

Humans impact fire in many ways. They may reduce ignitions by implementing fire suppression protocols or increase fire incidence through accidental or prescriptive ignitions. Anthropogenic changes to climate affect wind speeds and temperature that in turn may translate to more dangerous fire behaviour. Importantly for this discussion, humans also change the species composition of plant communities either directly by moving plant propagules or indirectly by affecting climate which in turn affects the geographical distribution of plants. Largely because of human actions, Western United States have witnessed drastic increases in the geographic distribution and severity of several important fire-adapted exotic plant species including Bromus tectorum (cheatgrass), Cenchrus ciliaris (buffelgrass), Ventenata dubia (ventenata), Taeniatherum caput-medusae (medusahead), Arundo donax (giant reed), and others. A recent United Nations study finds "the management of invasive alien vegetation is crucial for the prevention of extreme wildfires". The increase of invasive plants that are fire-adapted has changed the fire regimes in the American West fundamentally leading to more frequent and intense fires. Altered fire regimes have significant human and environmental-health consequences and threaten the economic sustainability of communities broadly, especially in the wild-land-urban interface. In California, seven of the 20 deadliest fires on record and 11 of the 20 most destructive fires have occurred in the past five years. Exposure to smoke from wildfires can have severe health consequences broadly across the region. Environmental degradation and severe wildfire events associated with exotic plant invasion have had significant impacts on rare, threatened and endangered species.

The Plant Species Composition of an Abandoned Meadow as an Element of an Ecosystem Mosaic within an Urban-Industrial Landscape

The absence of traditional management in grasslands is responsible for the consequent changes in plant community species composition and diversity of this habitat in Europe. The common reason for these changes is the spread of expansive native species such as Calamagrostis epigejos (L.) Roth and their subsequent dominance over other component species. The aim of the study was to determine the effect of management treatments (e.g., mowing, harvesting biomass) and their frequency of application (e.g., once or twice a year) on the cover abundance of C. epigejos (L.) Roth and the subsequent changes in component grassland species richness and diversity (Shannon–Wiener index) of an abandoned meadow in Silesia in S. Poland. A difference in species richness was found after five years of mowing, but an increase in species diversity appeared only after seven years of the treatments. Significant increases in species richness and Shannon–Wiener index and a significant decrease in cover abundance of C. epigejos (L.) Roth were recorded after different periods and for different treatments.

Species diversity is a strong predictor of ecosystem multifunctionality under altered precipitation in desert steppes

With the intensification of global climate change, the precipitation patterns are altered and grassland ecosystem is facing biodiversity loss and ecosystem services decline. It is of ecological significance to explore the underlying mechanisms of change in multiple ecosystem functions and services (multifunctionality) under altered precipitation. Plant community diversity (species, functional and phylogenetic diversity) has been proposed inducing links between ecosystem multifunctionality and environmental changes. However, which facet of plant community diversity can predict ecosystem function better remains controversial. Here, species, functional and phylogenetic diversity were investigated along precipitation gradients (−60%, −40%, −20%, CK, +20%, +40% and +60%) in the desert steppe of Inner Mongolia. In addition, ecosystem multifunctionality indices (averaging multifunctionality and threshold multifunctionality) were determined by eleven functions to assess the relationship between plant community diversity and multifunctionality under altered precipitation. We found that +40% and +60% precipitation significantly increased species richness by 52% and 33% and increased averaging multifunctionality by 20% and 46%. Functional and phylogenetic diversity at +60% precipitation were significantly higher than that at −60% treatment. Multifunctionality indices were positively correlated with precipitation gradients and plant community diversity. Importantly, species diversity possessed stronger predictive power of averaging multifunctionality than functional and phylogenetic diversity, which explained averaging multifunctionality of more than 38%. These results indicate that altered precipitation can change species composition of plant community and functions of ecosystem, further resulting in the closed relationship between species diversity and ecosystem multifunctionality. Our results highlight the critical role of species diversity in predicting multifunctionality of the altered precipitation conditions in desert steppes.

Species composition of semi‐natural mesic grasslands as a factor influencing the methane yield of plant biomass (Central Europe)

AbstractSemi‐natural lowland and mountain mesic meadows are grasslands rich in species, and their conservation status depends on treatments such as mowing or grazing livestock. In many countries, the condition of grasslands is deteriorating because of their inappropriate use or abandonment. This study aimed to determine the effects of the species composition of plant communities and functional plant groups on the methane yield from biomass harvested from mesic grasslands in the Sudetes Mountains. Biogas potential analysis was performed based on biomass samples collected from Poland and the Czech Republic. The biogas potential was determined in 40 day‐long batch anaerobic digestion tests. The average methane yield obtained from the biomass was 246 ± 16 NL CH4 kg−1 VS, whereas the methane yield per hectare was 870 ± 203 m3 CH4 ha−1. Plant communities comprising different dominant species had no effect on the methane yield but affected the methane yield per hectare. Additionally, the species composition of grasslands with a higher percentage of forbs had lower biomass yield, resulting in lower methane yields per hectare. The continuity of the low‐intensity management of mountain grassland, which can be provided by the utilization of their biomass for bioenergy production, sustains high biodiversity and ensures appropriate meadow conservation.

Drought, nitrogen deposition and arthropod herbivory modify plant establishment dynamics after soil disturbance

Global change projections predict more recurrent and intense drought coupled with more frequent soil disturbance events and increased levels of N deposition related to intensive land-use. How these abiotic drivers interact with each other and with biotic drivers in determining plant community dynamics is still unclear.Our study aimed to disentangle the roles of biotic and abiotic drivers in plant natural succession after soil disturbance. We carried out a factorial field experiment in which we performed soil disturbance in two seasons and manipulated drought, N deposition and herbivory. After each disturbance event, we monitored plant establishment dynamics.The species composition of plant communities established after disturbance was different in the early and late season trial probably due to different phenology of species from the seed bank. Depending on the timing of disturbance, plant communities responded differently to drought and N. In particular, seedling emergence and growth appeared sensitive to water stress only in the late season trial. Irrespective of the other treatments, arthropod herbivores increased the number of plant species established after soil disturbance. N generally had a negligible effect on plant community dynamics. We only observed positive effects of N on plant biomass in in the late season trial when there was a high water availability.Under future global change, we expect drought to affect plant establishment after soil disturbance by interacting with biotic and abiotic drivers. In particular, we showed that overlooked drivers such as timing of soil disturbance and arthropod herbivory will play an important role in shaping novel plant communities. Our results stress the critical need to adopt a multiple factor approach when assessing global change impacts on plant community diversity, composition and recovery ability.

Topography and soil content contribute to plant community composition and structure in subtropical evergreen-deciduous broadleaved mixed forests

Topography and soil factors are known to play crucial roles in the species composition of plant communities in subtropical evergreen-deciduous broadleaved mixed forests. In this study, we used a systematic quantitative approach to classify plant community types in the subtropical forests of Hubei Province (central China), and then quantified the relative contribution of drivers responsible for variation in species composition and diversity. We classified the subtropical forests in the study area into 12 community types. Of these, species diversity indices of three communities were significantly higher than those of others. In each community type, species richness, abundance, basal area and importance values of evergreen and deciduous species were different. In most community types, deciduous species richness was higher than that of evergreen species. Linear regression analysis showed that the dominant factors that affect species composition in each community type are elevation, slope, aspect, soil nitrogen content, and soil phosphorus content. Furthermore, structural equation modeling analysis showed that the majority of variance in species composition of plant communities can be explained by elevation, aspect, soil water content, litterfall, total nitrogen, and total phosphorus. Thus, the major factors that affect evergreen and deciduous species distribution across the 12 community types in subtropical evergreen-deciduous broadleaved mixed forests include elevation, slope and aspect, soil total nitrogen content, soil total phosphorus content, soil available nitrogen content and soil available phosphorus content.

Effects Exercised by Artificial Forest Stands on the Restoration of Secondary Virgin Lands in Agroforest Landscapes of Dry Steppes

For the first time, mathematical methods are used to assess the restoration of secondary virgin lands on dry-steppe fallow lands under the influence of artificial protective forest stands, a mandatory component of modern agroforest landscapes. Using variance analysis, Spearman’s rank correlation coefficient, and the method of correlation pleiades, it is established that artificial stands significantly affect the species composition of plant communities. The greatest impact of cluster forest stands on the species composition of plant communities is observed in their immediate vicinity. The study objects located far from the forest stands feature the maximum similarity coefficients with the virgin lands. It is shown that fallow lands in edge zones of artificial stands planted in a linear fashion are similar to phytocoenoses of adjacent areas by their species composition.

Vaccinium myrtillus L. в Кировской области (южно-таежная подзона): фитоценотическая приуроченность, экологические предпочтения

Vaccinium myrtillus L. is an important component for forming phyto-environment in boreal forest ecosystems, in which it develops various consortium connections. Being a mycorrhizal species, V. myrtillus improves nutrition and stimulates the growth of plants of all layers, supporting inter- and intra-specific connections of different layers of forest communities. In order to estimate the environment-forming role of V. myrtillus in ecosystems it is essential to acquire data on quantitative presence of the species in plant communities composition and on ecological-phytocoenotic peculiarities within its range. The aim of the study is to define phytocoenotic parameters and ecological conditions of V. myrtillus habitats within the southern taiga part of its range (Kirov region). We collected the material during the growing seasons of 2009-2015 and made 110 geobotanical descriptions according to common geobotanical methods (Methods of studies…, 2002). Ecological conditions were estimated based on species compositions in communities using 10 ecological scales by Dmitry Tsyganov (1983). The ecological discomfort index was determined for each habitat (Klimenko, 2012). Common methods of soil analyses were used for different biotopes of the studied species (Arinushkina, 1962). Hemeroby was determined by the species composition in plant communities, in which every species has individual human impact tolerance spectre (Frank and Klotz, 1990). V. myrtillus acts as a dominant or codominant of the herbaceous-shrub synfolium of boreal coniferous and mixed forest communities with 30-70% cover. It is accompanied by the following species: Vaccinium vitis-idaea L., Rubus saxatilis L., Juncus filiformis L., Calamagrostis epigeios (L.) Roth., Thelypteris palustris Schot, Melampyrum sylvaticum L., and Majanthemum bifolium (L.) F. Schmidt. The species is found on gley and gleyic podzolic soils, mostly sabulous, rarely-sandy; and on peatygley and sod-podzolic soils (See Table 1). Bilberry is common on high acidity soils with pH varying from 2.54 to 4.93. The concentration of organic carbon in bilberry forest litter varies from 5.71 to 69.2% (See Fig. 1). V. myrtillus is a mesobiont species whose average ecologic valency coefficient reaches 55%. In the investigated coenopopulations, the species achieves 8.15 to 50.10% of its potential capabilities regarding the studied factors. V. myrtillus is a hemieurybiont by climatic factors (0.58 points). It achieves its maximum on ombroclimatic scale (44.5%). According to climatic scales, ecological conditions of the studied habitats occupy the central position of all possible. The generalized spectrum of soil scales shows the species as a mesobiont (It–0.45). This allows widening V. myrtillus soil humidity scale 1.27 point left and soil moisture variability scale 0.80 points right. On other scales, the environmental position of the studied coenopopulations are within the data given by Dmitry Tsyganov for the species (See Table 2 and Fig. 2). The discomfort index is also given to estimate habitat ecological conditions. Based on phytoindication data and according to the discomfort index, we defined that the most favorable conditions of edapho- and climatopes for V. myrtillus are formed in sphagnum phytocoenoses. The least favorable conditions were noted in bilberry pine and bilberrypleurocarpous moss pine-spruce forest types. The study of hemeroby showed that oligo-mesohemerob species (highly sensitive to anthropogenic factors) prevail in all V. myrtillus coenopopulations, i.e. 41%. A-hemerob, a-euhemerob and polyhemerob species were not noted in any of the studied CPs (See Table 3 and Fig. 3). This proves that the species is of low resistance to anthropogenic influence and can survive moderate intensity human impact. The studied plant communities with V. myrtillus are low-hemerobic.