Phytomass change in natural phytocenosis as an indicator of technogenic pollution of soils with heavy metals

This study considered the possibility of using plant community phytomass for the assessment of soil pollution with heavy metals (HM) from industrial wastes. The three-year-long field experiment was run under the regional natural meadow vegetation; the polymetallic galvanic slime was used as an industrial waste contaminant. It is shown that soil contamination primarily causes decrease of phytomass in the growing phytocenosis. The vegetation experiments determined nonlinear dependence of cultivated and wild plant biomass on the level of soil contamination; it is described by the equations of logistic and Gaussian regression. In the absence of permanent contaminants, the soil is self-cleaned over time. It reproduces phytomass mainly due to the productivity increase of the most pollution-tolerant species in the remaining phytocenosis. This phenomenon is defined as environmental hysteresis. Soil pollution by industrial waste leads to the loss of plant biodiversity. The research shows that the study of the HM impact on ecosystems is expedient given the consideration of the “soil–phytocenosis–pollutant” complex in the “dose–response” aspect. The reaction of phytocenosis on HM showing decline in phytomass leads to serious limitations in the choice of accumulating plants, because the adsorbed HM are rejected through phytomass.     

The carrying-out of 90Sr and 137Cs by the overground phytomass plant communities of the meadows and of the fallow lands of Chernobyl Exclusion Zone

Below are presented the results of the researches of the carrying-out of 90Sr and 137Cs by the overground phytomass of the fallow lands and meadows herbaceous community of Chernobyl Exclusion Zone (Zone). The radioecological characteristic of the basic cenosis-generative species of the Zone's fallow lands and meadows herbaceous communities is given. Are made the evaluations of the biogenic fluxes of the radioactive matters into structural elements of the mentioned phytocenosises (alive biomass and laying). The radioecological significance of the Zone's herbaceous phytocenosis is presented as one of the bariers on the ways of the carrying-out of the radioactive nuclides out of the borders of the zone.     

A grass mire in Poland: Reserves of phytomass and deposited nutrition elements

The reserves of phytomass and deposited nutrition elements in a grass mire have been estimated. Two grass mires and one sphagnum bog are compared in these parameters. The sphagnum bog and one grass mire are in Poland, and the other grass mire is in Russia. As follows from the comparison, the common climatic and geochemical properties of location have effect on the chemical nature of phytomass. Grass mires have a higher content of nitrogen than sphagnum bogs. Both of the Polish bogs exhibit an increased content of K and a decreased content of Ca. The accumulation of P is characteristic of the Siberian grass mire and the accumulation of S is found in the Polish one.     

Differentiation between responses of primary productivity and phosphorus exploitation to species richness

Several studies have shown that ecosystem functioning increases with increasing species richness. Most of these studies examined the effects of species richness on primary productivity. The underlying mechanism that explains this pattern is usually the selection effect. The higher the diversity in plant communities the higher the chance in including a very productive species that dominates the community, or a legume species that brings N into the soil. Less attention has been given so far to the effects of species richness on phosphorus exploitation. The aim of this work was to investigate the effect of species richness on aboveground primary productivity and P accumulation in a plant diversity experiment. For this reason, 14 grassland plant species were grown in containers as monocultures and in mixtures of 2-, 3-, 4-, 8-, 11- and 14-species combinations. Results show that the aboveground phytomass and total P increased with increasing species richness. Complementarity effects, probably through partitioning of resources, were most apparent in the highest levels of species richness, and were observed to be greater for total P in comparison to phytomass. Selection effects generally were greater for phytomass than for total P; they were significantly positive at the 2- to 8-species combinations but close to 0 or negative in the highest levels of species richness. The increases in phytomass and total P at the highest levels of species richness appeared to be caused by the increased performance of intermediate-productive species. Responsible Editor: Tibor Kalapos.     

Simulation of phytomass productivity based on the optimum temperature for plant growth in a cold climate

During long-term monitoring (more than 20 years) of the hydrologic regime at 20 mountainous sites in the Czech Republic (altitude 600–1400 m a.s.l.; vegetation season April-September; mean air temperature 8–10°C; mean total precipitation 400–700 mm; mean duration of sunshine 1100–1300 hours; mean potential transpiration 200–250 mm) it was found that plant temperature does not rise above about 25°C when plants transpire. According to the ecological optimality theory, the phytocenosis that is able to survive unfavourable conditions and produce the biggest amount of phytomass will prevail at sites occurring in long-term stable natural conditions. Simulation of phytomass productivity based on the optimum temperature for plant growth showed that plants with an optimum leaf temperature of about 25°C can survive the unfavourable conditions and produce the largest amount of phytomass at the site studied in the long-term.     

The dynamics of accumulation of above-ground phytomass by technogenic communities in the course of their natural progressive successional replacement in the Norilsk Industrial District

It has been revealed that the above-ground phytomass in pit-wall communities increases most rapidly during the first succession stage, i.e., when plants colonize bare grounds. In following succession stages, the accumulation of phytomass slows down, with phytocenotic composition changing considerably. The above-ground phytomass in dump phytocenoses increases gradually in all succession stages.     

Effects of grazing exclusion on plant species richness and phytomass accumulation vary across a regional productivity gradient

Question: Does long‐term grazing exclusion affect plant species diversity? And does this effect vary with long‐term phytomass accumulation across a regional productivity gradient? Location: Lowland grassy ecosystems across the state of Victoria, southeast Australia. Methods: Floristic surveys and phytomass sampling were conducted across a broad‐scale productivity gradient in grazing exclusion plots and adjacent grazed areas. Differences in species richness, evenness and life‐form evenness between grazed and ungrazed areas were analysed. The environmental drivers of long‐term phytomass accumulation were assessed using multiple linear regression analysis. Results: Species richness declined in the absence of grazing only at the high productivity sites (i.e. when phytomass accumulation was >500 g m^?2). Species evenness and life‐form evenness also showed a negative relationship with increasing phytomass accumulation. Phytomass accumulation was positively associated with both soil nitrogen and rainfall, and negatively associated with tree cover. Conclusions: Competitive dominance is a key factor regulating plant diversity in productive grassy ecosystems, but canopy disturbance is not likely to be necessary to maintain diversity in less productive systems. The results support the predictions of models of the effects of grazing on plant diversity, such as the dynamic equilibrium model, whereby the effects of herbivory are context‐dependent and vary according to gradients of rainfall, soil fertility and tree cover.     

Contribution to the ecology ofStipa species in central Europe: Distribution of mineral elements in soils and phytomass

In 1963, 1964 and 1965, a comparative ecological study was made of the distribution of mineral elements in the soil and phytomass of some Stipa species, viz.Stipa capillata L., S. pulcherrima C. Koch,S. joannis ?elak.,S. dasyphylla ?erň.,and S. stenophylla ?erň. in various locations of Central Europe. In all species and sites studied, chemical analyses of the soil, fresh phytomass (shoots and roots) and dead phytomass were made, together with relevant statistical evaluation. IndividualStipa species differ according to their mineral composition. In comparison with fresh green plant material, the old dead plant material shows a marked increase in ash, calcium, and natrium content. Potassium, nitrogen, and phosphorus show a decrease in the dead plant material. The mineral composition of the roots differs considerably from that of green plant parts: the roots have much higher ash, phosphorus, calcium and natrium content, and lower organic matter, nitrogen, and potassium content. On the basis of the data collected, an attempt was made to estimate cycling of the individual mineral elements.     

Earthworm (Oligochaeta,Lumbricidae) Populations of the Karasu River Basin (Central Caucasus)

The species composition, population structure, and synecological characteristics of earthworms inhabiting forest and meadow formations of unique beech–hornbeam woodland of the Karasu River basin have been studied. Thirteen Lumbricidae species were found. The species composition and earthworm population structure depend on phytocenosis edificators. The greatest diversity, namely, species, chorological, and ecological, was recorded in soils of relict beech phytocenosis. It was shown that in the case of forest clearing its earthworm’s fauna remains intact. In the secondary meadows, the following was noted: the lowest species diversity of Lumbricidae, domination of soil species proper, and dramatically increasing diversity indices compared to forest associations.     

90Sr, 137Cs, 238Pu, 239+240Pu,and 241Am radionuclides in macrophytes within the Krasnensky flood plain: species specificity of concentration and distribution in phytocenosis components

The analysis of the content of radionuclides 90Sr, 137Cs, 238Pu, 239 + 240Pu and 241Am in water vegetation of flood plain reservoirs has allowed studing features of radionuclide accumulation by various species of macrophytes and revealing bioindicators of radionuclide contamination. Thus species-specificity of radionuclide accumulation can essentially change the contribution of different species to a percentage ratio of the radionuclide content in phytomass of reservoirs in comparison with fund of higher aquatic plants.     

Estimation of forest-stand net primary productivity using fraction phytomass distribution model

Methods for assessing the primary productivity of the forest stands between various tree species in different environmental conditions are considered. Methods for the primary productivity assessment using data on the phytomass fractions and stand wood stock have been proposed. It is shown that the Zipf-Pareto equation of the relationship between the phytomass of some tree fractions in the stand can be used for a primary productivity estimation of the stock volume. A model analogous to R. Solow’s macroeconomic model has been proposed to describe the processes of the phytomass growth in the forest stand.     

Site parameters,species composition,phytomass structure and element stores of a terra-firme forest in East-Amazonia,Brazil

Our objective was to asses site parameters, species diversity, phytomass structure and element stores of a Terra-firme forest prior to subsequent studies on nutrient fluxes during forest conversion. The soil was classified as a Xanthic Ferralsol, with a low effective cation exchange capacity (ECEC), low nutrient status and a deeply weathered solum. On 0.75 ha, including all trees with a DBH >7 cm, we identified 222 tree species belonging to 58 families. The above-ground phytomass was estimated using logarithmic regression analysis on two plots of 0.25 ha each. Despite differences in forest structure and species composition, no major differences were found in terms of total phytomass or overall element stores. The mean living above-ground phytomass (LAGP) was 257 Mg ha^–1, and mean quantity of litter 14 Mg ha^–1, while dead wood contributed between 10 to 17% of total above-ground phytomass (32–56 Mg ha^–1). Element store in LAGP was medium to high compared to other studies on tropical forest systems, while LAGP itself was comparatively low. Comparing 26 humid tropical forest stands recorded in literature, no correlation was found between LAGP and the amount of N and base cations stored in LAGP. However, a correlation between LAGP and P storage in LAGP (R ²=0.76) indicates the important role P may play in phytomass accumulation on zonal tropical soils. More then 60% of C, 20% of total N, 10% of total P and 66–88% of total K, Ca and Mg of the system (including the first meter of soil) were concentrated in the above-ground phytomass, including deadwood and litter. Consequently, phytomass destruction in form of forest conversion will lead to major element losses from the system.     

Production and spatial structure of Mediterranean pastures in different stages of ecological succession

The aim of this paper is to describe the changes of Mediterranean pasture phytomass and their dependence on succession, slope geomorphology and herbivore consumption. Four neighbouring slopes of similar aspect and steepness, located in a pasture area of Central Spain, were chosen for sampling. The slopes had not been cultivated for 1, 3, 8 and 40 years respectively. On each slope both the upper, erosion zone and the lower, accumulation zone were sampled during the months of plant growth (April to July), phytomass being recorded in plots where herbivore consumption was avoided with protection cages and in unprotected plots.Results from the protected plots show that the upper and lower parts of slopes undergo a different development during succession. The highest values of phytomass reached, tended to decrease during succession in the upper zones, the same being true for production. However in the lower zones both parameters tended to increase in time. The ratio P/B, widely known in ecology to decrease with time, did not seem to behave as a usual index of succession in the studied ecosystem. In the upper zone this ratio tended to decrease but in the lower zone it increased with succession after the first years.Phytomass consumption by herbivores was progressively concentrated during succession in the slope sectors of greater production, mainly in the lower zone, which increased its productivity as the slope-talweg system became functional. The evolution of the ecological structure of a slope should be interpreted not only as a result of the tolerance of species to phsysico-chemical factors. It may also reveal the existence of an important interaction between the pasture and the grazing behaviour of exploiting animals. Multivariate analysis of phytomass records revealed a trend of temporal variation which should be identified with the progress of succession.     

Herbaceous phytomass and nutrient concentrations of four grass species in Sudanian savanna woodland subjected to recurrent early fire

Fire is an integral ecological factor in African savanna ecosystems, but its effects on savanna productivity are highly variable and less understood. We conducted a field experiment to quantify changes in herbaceous phytomass and nutrient composition in a Sudanian savanna woodland subjected to annual early fire from 1993 to 2004. Fire effects were also assessed on two perennial and two annual grass species during the following growing season. Early fire significantly reduced above‐ground phytomass of the studied species (P = 0.03), their crude protein (P = 0.022), neutral detergent insoluble crude protein (P = 0.016) and concentrations of Ca, Fe and Mn (P < 0.05). Perennial grasses had higher above‐ground phytomass but lower total crude protein and fat than annual grasses. Nonstructural carbohydrates tended to be higher for annuals, while fibre and lignin contents were high for perennials. Except Na and Fe, the concentration of mineral elements varied between species. Fire did not affect measures of digestibility and metabolizable energy, but its effect differed significantly among species. In conclusion, the results illustrate that long‐term frequent fire will counterbalance the short‐term increase in soil fertility and plant nutrient concentrations claimed to be accrued from single or less frequent fire.     

Phytomass utilization and deposition of feces by ungulates on steppe pastures of eastern Mongolia

The amount of phytomass removed by a complex of livestock (horses, cattle, sheep, and goats) and wild ungulates (Mongolian gazelle Procapra gutturosa Pall.) grazing in plain and mountain pastures of eastern Mongolia has been estimated by taking account of feces deposited by these animals. The results show that at an animal density of up to 30 head/km², the total annual amount of feces reaches 140 kg/ha (dry weight), with the greater part (up to 90 kg/ha) being deposited by horses. The contribution of Mongolian gazelles in some pastures reaches 20–40 kg/ha per year. Decomposition of feces proceeds very slowly, with the annual loss of their weight averaging only 9–12%. This is evidence for gradual accumulation of nondecomposed matter in the soil. The removal of phytomass by the complex of ungulates, calculated from the amount of feces with regard to their annual loss and forage digestibility, varies in different grazing areas from 240 to 400 kg/ha (25–60% of the total aboveground phytomass). The greatest amount of phytomass is utilized by horses, reaching 200 kg/ha (13%), and Mongolian gazelles utilize up to 86 kg/ha per year. In the growing season, ungulates remove no more than 11–16% of the total aboveground phytomass. It is concluded that the impact of total ungulate stock does not impair the productivity of vegetation in the pastures studied.     

Current state of forage resources and feeding of reindeer (<Emphasis Type="Italic">Rangifer tarandus</Emphasis>) and musk oxen (<Emphasis Type="Italic">Ovibos moschatus</Emphasis>) in the arctic tundras of Wrangel Island

The species composition and aboveground biomass of plant and lichens and the composition of reindeer and musk ox diet in the arctic tundra of Wrangel Island were studied in 2004 to 2007. The above-ground phytomass in different areas of the island varied from 1105 to 2100 kg/ha. The composition of plants consumed by reindeer and musk oxen and their proportions in the diet were determined by standard micro-histological analysis of plant remains in their feces. The results showed that, either in winter or in summer, both species obviously preferred feeding on willows (Salicaceae), which comprised almost half of their diet. Moreover, their feeding was highly selective, especially with respect to sedges and rushes (Cyperaceae + Juncaceae) and legumes (Fabaceae). Although the contributions of these plant groups to the total aboveground phytomass were very small (less than 4 and 8%), their proportions in the diet reached 27 and 24%, respectively. Mosses were not a preferred forage: their proportion in the aboveground phytomass reached 40%, but that in the diets of both species was below 10% in summer and increased to 20% only in the winter diet of reindeer. At a high abundance of lichens (up to 20% of the aboveground phytomass), neither of the animals consumed them during the study period.     

Chemistry of medicinal plants (review)]

Data on the chemical composition related to synthesis of physiologically active substances (alkaloids, terpenoids, glycosides, phenolic compounds, etc.), and accumulation of individual elements or groups of five to ten elements (e.g., Cr, Co, Mn, and Zn) in medicinal plants were reviewed. Chemical features of medicinal plants serve as an integral determinant of their species specificity and pharmacological properties and enabling their wide use in medical practice. The relationship between the synthesis of physiologically active substances and accumulation of elements is mediated by several levels of molecular regulation.     

Trophic levels of small mammals: Multi-elemental composition and toxic load

The chemical compositions (25 elements) of the diet and carcass of two sympatric small mammal species (Clethrionomys glareolus and Sorex caecutiens) inhabiting near a large copper smelter and in unpolluted area (Middle Ural, Russia) have been analyzed and compared. The group of phytophages is shown to play a special role in the translocation of chemical elements over the trophic levels of mammals. Specific features of the diet and a barrier at the gastrointestinal level limit accumulation of chemical elements in the animal body. Under the same conditions, carnivores act in the mammal community as concentrators of several elements (Pb, Cd, Cr, and As), displaying increased their concentrations in the body as compared with the diet. On the other hand, the toxic load on the animal organism is independent of trophic specialization.     

Chemical Features of Medicinal Plants (Review)

Data on chemical composition related to the synthesis of physiologically active substances (alkaloids, terpenoids, glycosides, phenolic compounds, etc.) and to the accumulation of individual elements or groups of five to ten elements (e.g., Cr, Co, Mn, and Zn) in medicinal plants were reviewed. Chemical features of medicinal plants serve as an integral determinant of their species specificity and pharmacological properties and enable their wide use in medical practice. The relationship between the synthesis of physiologically active substances and accumulation of elements is mediated by several levels of molecular regulation.     

The Current State of the <Emphasis Type="Italic">Zostera marina</Emphasis> + <Emphasis Type="Italic">Stephanocystis crassipes</Emphasis> Community in the Eastern Bosphorus Strait,Sea of Japan

The state of the macrophyte community of Zostera marina + Stephanocystis crassipes in the cove off Cape Tokarevsky (Eastern Bosphorus Strait, Sea of Japan) was evaluated, using the method of sample plots, in June 2014. The taxonomical and morpho-functional composition, as well as the structure of the community, has been studied. A total of 39 species of marine macrophytes have been found in this area, including 6 species of Chlorophyta, 22 species of Rhodophyta, 10 species of Phaeophyceae, and 1 species of Tracheophyta (Zostera marina), which constitute 15, 56, 26, and 3% of the total number of species in the community, respectively. The studied phytocenosis is characterized by a poor taxonomic composition, a high biomass of opportunistic species (auxiliary species on the dominance scale), and the proportions of higher algal taxa typical of the clean waters of Peter the Great Bay. Thus, based on a combination of these characteristics, the Zostera marina + Stephanocystis crassipes phytocenosis can be regarded as being in an early stage of anthropogenic transformation and the waters are classified as moderately polluted.