Edaphic Characteristics Research Articles

Modelling modulus of elasticity of Pinus pinaster Ait. in northwestern Spain with standing tree acoustic measurements, tree, stand and site variables

Aim of study: Modelling the structural quality of Pinus pinaster Ait. wood on the basis of measurements made on standing trees is essential because of the importance of the species in the Galician forestry and timber industries and the good mechanical properties of its wood. In this study, we investigated how timber stiffness is affected by tree and stand properties, climatic and edaphic characteristics and competition. Area of study: The study was performed in Galicia, north-western Spain.Material and methods: Ten pure and even-aged P. pinaster stands were selected and tree and stand variables and the stress wave velocity of 410 standing trees were measured. A sub-sample of 73 trees, representing the variability in acoustic velocity, were felled and sawed into structural timber pieces (224) which were subjected to a bending test to determine the modulus of elasticity (MOE). Main results: Linear models including wood properties explained more than 97%, 73% and 60% of the observed MOE variability at site, tree and board level, respectively, with acoustic velocity and wood density as the main regressors. Other linear models, which did not include wood density, explained more than 88%, 69% and 55% of the observed MOE variability at site, tree and board level, respectively, with acoustic velocity as the main regressor. Moreover, a classification tree for estimating the visual grade according to standard UNE 56544:2011 was developed. Research highlights: The results have demonstrated the usefulness of acoustic velocity for predicting MOE in standing trees. The use of the fitted equations together with existing dynamic growth models will enable preliminary assessment of timber stiffness in relation to different silvicultural alternatives used with this species.Keywords: stress wave velocity, modulus of elasticity, site index, competition index, stepwise regression, CART.

Predicting the responsiveness of soil biodiversity to deforestation: a cross‐biome study

The consequences of deforestation for aboveground biodiversity have been a scientific and political concern for decades. In contrast, despite being a dominant component of biodiversity that is essential to the functioning of ecosystems, the responses of belowground biodiversity to forest removal have received less attention. Single-site studies suggest that soil microbes can be highly responsive to forest removal, but responses are highly variable, with negligible effects in some regions. Using high throughput sequencing, we characterize the effects of deforestation on microbial communities across multiple biomes and explore what determines the vulnerability of microbial communities to this vegetative change. We reveal consistent directional trends in the microbial community response, yet the magnitude of this vegetation effect varied between sites, and was explained strongly by soil texture. In sandy sites, the difference in vegetation type caused shifts in a suite of edaphic characteristics, driving substantial differences in microbial community composition. In contrast, fine-textured soil buffered microbes against these effects and there were minimal differences between communities in forest and grassland soil. These microbial community changes were associated with distinct changes in the microbial catabolic profile, placing community changes in an ecosystem functioning context. The universal nature of these patterns allows us to predict where deforestation will have the strongest effects on soil biodiversity, and how these effects could be mitigated.

Elemental and stable isotope composition of Pinus halepensis foliage along a metal(loid) polluted gradient: implications for phytomanagement of mine tailings in semiarid areas

Aleppo pine (Pinus halepensis Mill.) is a widely used species for restoring degraded semiarid areas, but its use for the revegetation of metal(loid) polluted soils has not been thoroughly investigated. The main goal of this research was to study the ecophysiological status and elemental composition of spontaneous populations of Pinus halepensis growing on mine tailings to assess their use in phytomanagement of mine spoils in semiarid climates. Edaphic characteristics and the physiological (by stable isotopes) and nutritional status of pine trees were determined on mine tailings, in the metalloid-polluted surroundings and a non-polluted control area. Low soil phosphorus availability at the tailings was found to be a more important limiting factor for pine physiological performance than high soil metal(lloid)s concentrations. Foliar phosphorus concentrations showed a strong negative correlation with foliar sulphur concentrations along the studied transect. The carbon and oxygen isotopic composition (δ13C and δ18O) of pine needles indicated that trees at the tailings were less water stressed than those in surroundings or control areas. The low foliar δ15N of pines growing at the tailings was due to low soil fertility and/or a heavy reliance on symbiotic ectomycorrhizal fungi for nitrogen uptake. The results of this study indicate that Pinus halepensis is a suitable tree species for the phytostablisation of neutral or slightly-alkaline mining wastes in semiarid environments, thanks to its drought hardiness and good adaptation to low soil fertility and salinity.

Soil physical properties influence “black truffle” fructification in plantations

Although the important effects of pH and carbonate content of soils on "black truffle" (Tuber melanosporum) production are well known, we poorly understand the influence of soil physical properties. This study focuses on physical soil characteristics that drive successful production of black truffles in plantations. Seventy-eight Quercus ilex ssp. ballota plantations older than 10years were studied in the province of Teruel (eastern Spain). Soil samples were analyzed for various edaphic characteristics and to locate T. melanosporum ectomycorrhizae. The influence of cultivation practices, climatic features, and soil properties on sporocarp production was assessed using multivariate analyses. Low contents of fine earth and silt and high levels of bulk density, clay content, and water-holding capacity appear to promote fructification. Watering is also highly positive for truffle fructification. We develop and discuss a logistic model to predict the probability of truffle fructification in field sites under consideration for truffle plantation establishment. The balance between water availability and aeration plays a crucial role in achieving success in black truffle plantations.

Relation Between Edaphic Factors and Vegetation Development on Copper Mine Wastes: A Case Study From Bor (Serbia, SE Europe)

The relationship between edaphic characteristics and vegetation growing on mine wastes in the Bor region (East Serbia, SE Europe) was studied using multivariate statistical analysis. The influence of edaphic factors on the composition of plant life-forms was also investigated, since it could reflect strategies for the avoidance of or tolerance to disturbances of ecosystems. The goal was to provide potential models for the restoration and management of this and similar mine waste areas. The results of this study imply that soil textures, nitrogen contents, reclamation technology and the presence of hydrothermally altered andesite as the type of bedrock significantly influenced plant colonization and vegetation composition of the Bor mine wastes. These edaphic factors explained 30.3 % of the total variation in the vegetation data set. It was also revealed that the pattern of plant life-forms found on the considered site groups corresponded to the soil texture. Based on their relative abundance on the investigated sites and relationships with soil properties it is concluded that therophytes and geophytes are unsuccessful primary colonizers of the Bor mine wastes. Hemicryptophytes of psammophytic character were the most successful primary colonizers and therefore potential candidates for anthropogenically-assisted natural recovery. This study suggested that an assessment of edaphic factors should be widely used in the characterization of mine wastes prior to reclamation. Estimation of their role in the development of existing mine vegetation should predate reclamation procedures. Thus, approaches based on adequate plant life-forms should have a more prominent role in future mine reclamation schemes.

Altered Plant-community Composition and Edaphic Features Associated with Plowing in Southern Wisconsin Fens

The potential for land-use legacies to alter current wetland macrophyte communities and edaphic conditions are underexplored. Here we present results of a study describing associations among these factors in southern Wisconsin fens. Plant-community composition, hydrology, and nutrient availability data were recorded from 1) fens that had been plowed, 2) fens that have never been plowed, and 3) fens with plowed and never-plowed areas. Plowed fens had: 1) lower total species richness, 2) higher invasive species richness, 2) lower native graminoid richness, 3) lower shrub richness, 4) lower root-zone volumetric water content, and 5) higher available N and P then never-plowed fens. Most of these same relationships held when comparing plowed and never-plowed areas of the same fen. Non-metric Multidimensional Scaling revealed that the most important community gradient separates graminoid- and fen-specialist-rich communities from those dominated by invasive species. This gradient also separated plowed from never plowed plots. Accordingly, we believe that a history of plowing has fundamentally altered biotic and, potentially, abiotic conditions, with real consequences for wetland management and restoration.

Direct Effects of Stubble Burning on Some Edaphic Characteristics of Coastal Plain Sands at Different Heating Intensities

Stubble burning had been identified as a contributor to soil structural degradation and loss of plant nutrients. Contrary to this, some studies have suggested that burning activities might increase availability of plant nutrients and also reported that charcoal residues and charred biomass left on kiln sites improve the fertility of tropical soils by direct nutrient addition and retention. The effect is not sufficiently understood or quantify in areas with very high rainfall intensity that evidenced in high leaching and erosion associated with slope. We; (1) examined the effect of stubbles burning on soil conditions in acid sands, and (2) identified any changes in soil chemical and physical properties under burning at different level of intensity. The experimental fire was performed with measured dry biomass of 30, 90, 120 kg m- 2 , in three replicates on the plots to provide three levels of burning and the unburned plots served as control. At each of the sampling points, random spots were core sampled and augered at 0-15 cm depth, with the aid of a Dutch auger and bulked together to give a composite sample. Laboratory methods of analyses were carried out on soil samples for particle size distribution, pH (soil reaction), organic matter contents, total nitrogen, available phosphorus and exchangeable cations (K, Ca, Mg and Na). The textural class of the soils within the study area was found to be sandy loam with sand fraction being the dominant particle size in all locations after burning and was found to have significant effect on the particle size distribution. Coarse sand fraction was higher in the burnt plot with the mean value of 16.00 gkg -1 in 30 and 120 kgm- 2 , 13.33 gkg -1 in 90 kgm- 2 and 12.66 gkg -1 in the unburnt plot. Also soil burnt with 30 and 90 kgm- 2 of the dry biomass was found to increase bulk density by 4 and 9 % respectively, while 6 % reduction in bulk density occurred in soil burnt with 120 kgm- 2 stubble materials. Total nitrogen content was found to be significantly reduced as a result of burning, while available phosphorus was higher in burnt plots than in the un-burned soil.

Evaluation of Characteristics Floristico-Edaphic of the Steppes at Alfa (<i>Stipa tenacissima</i> L.) in the Saida Region (Western Algeria)

To establish an assessment of floristic and edaphic characteristics of steppe formations we conducted a phytoecological study on a local scale by comparing the current plant diversity and soil in three (3) stations representative of the vegetation to alfa (Stipa tenacissima L.) located south of Saida (western Algeria). The relations between the station, the vegetation and the characteristics of soils in the steppe are very imperfectly known. This study intends to analyze the relationship between floristic composition and edaphic parameters of the steppe at alfa. Anthropogenic pressures on plant structure are different imbalance resulting in one ecological. The floristic and edaphic data have been the subject of a factorial correspondence analysis (A.F.C). The floristic inventory denotes a regressive dynamics of the formations at alfa passing from one site to another. Thus 39 plant species have been inventoried in the site in good condition, against 26 species for the moderately degraded site and 16 species only for the damaged site. The coupled results between species and edaphic parameters show the relations between the plant diversity and the physico-chemical characteristics of the soils. The statistical analyses do appear a strong correlation between floristic composition, the state of vegetation and the edaphic parameters.

Ecological and Climatic Attribute Analysis for Egyptian Hypericum sinaicum

Conservation of globally endangered plant resources is a critical ecological, cultural and economic issue. The undertaking of ecological study focusing on the distribution, abundance and population structures of target species is fundamental to the assessment of the conservation status of wild populations. A study was carried out on the wild herb Hypericum sinaicum (Family: Hypericaceae) in Saint Katherine Protectorate (SKP), South Sinai, Egypt, where 22 sites presenting different habitats in SKP were surveyed for: (1) investigate the floristic composition, vegetation types and H. sinaicum distribution in the area, (2) define the ecological status of H. sinaicum and characterize this range by its size, shape, boundaries and internal structure, (3) clearly identify conservation priorities and suggest appropriate strategies for H. sinaicum conservation, (4) detect the effect of environmental factors on the distribution of H. sinaicum in order to use it as first step for conservation by rehabilitation or restoration, (5) determine the effect of spatial variation on plant community and H. sinaicum productivity, and (6) to determine the ecological and climatic requirements for this species and detect their effect on the species distribution. A total of 113 species were recorded in total within the 237 sites. 37 families were recorded within the study area; Asteraceae (15%) and Lamiaceae (11.5%) presented the dominant families in this area, while the Hypercaceae family which represented the target species (H. sinaicum) was recorded only once. H. sinaicum was recorded as dominant species in only 12 sites from 237 with 5%. Morphological attributes for Hypericum showed great variation due to the variation in the edaphic features of different locations. Finally it’s was observed that vegetation constitutes an organized whole, it operates at a higher level of integration than the separate species and may possess emergent properties not necessarily found in individual themselves. Most of the H. sinaicum populations were small and the plants occurred sporadically in space, as little groups conjugated with wet soil. At the micro-site level, H. sinaicum plants occupied most of high altitude habitats in SKP such as cliffs, Wadi bed, terrace, gorge, slope and cave habitats. H. sinaicum prefers the wet and shady places like gorges, slopes and cliffs with continuous water supply. There is an urgent need to integrate the knowledge derived from ecological, demographic and climatic approaches to species conservation in order to be able to formulate management strategies that take into account all different considerations.

Vertical differentiation analysis of sierozem profile characteristics in Yili-River valley, China

Research on the vertical differentiation of sierozem profile characteristics can provide a basis to implement soil resource assessment and develop sustainable land management system. In this study, 189 sampling data from 50 sierozem profiles along Yili River-valley in northwest of China were chosen to analyze the vertical change of edaphic characteristics and soil ionic composition – including soil organic matter (SOM), pH value, electrical conductivity (EC), total salinity (TS), contents of CO32-, HCO3-, Cl-, SO42-, K+, Na+, Ca2+and Mg2+ in soluble salt. Then sierozem characteristics in Yili-River valley were compared with those in central Asia, Ningxia and Gansu provinces to reveal the vertical change and regional difference. The results showed that vertical difference of sierozem profile characteristics in different regions had some common: SOM content decreased with soil depth, while pH value, EC, contents of TS and most ions increased with soil depth. But there was obvious regional difference in spatial variation and intensity of sierozem characteristics due to more arid climate in Yili-River valley. The results could be used for regional ecological construction and sustainable development. Key words: Yili-River valley, sierozem, vertical differentiation.

ПРОСТРАНСТВЕННАЯ ОРГАНИЗАЦИЯ СООБЩЕСТВА ПОЧВЕННЫХ МЕЗОПЕДОБИОНТОВ В УСЛОВИЯХ РЕКРЕАЦИОННОЙ НАГРУЗКИ В ЛЕСОПАРКОВОМ НАСАЖДЕНИИ

<p>In work the results of studying of the spatial organization of soil mesofauna of the artificial forest planting have been processed by OMI- and RLQ-analysis methods. Our research were conducted in June, 6st, 2011 in Oles Gonchar University botanic garden (earlier – territory of park of J. Gagarin, Dnepropetrovsk). The studied plot is situated at a distance of 220 m from the Building 1 of DNU and at a distance of 95 m from Y. Gagarin Avenue (the Southeast direction) (48°25'53.88"С, 35°2'25.82"В). The plot consists of 15 transects directed in a perpendicular manner in relation to the Avenue. Each transect is made of seven sample points. The distance between points is 2 m. The coordinates of the lower left point have been taken as (0; 0). The plot represents artificial forest-park planting. The vegetation has typically wood, mesotrophic and mesophilic character (93.55% – silvants, 70.97% – mesotrophic, 57.84% – mesophiles). At each point the soil mesofauna was studied; temperature, electrical conductivity and soil penetration resistance, dead leaf layer and herbage height were measured. Soil-zoological test area had a size of 25×25 cm.</p> <p>In ecological structure of the soil animal community have been found such groups dominant as saprophages, pratants and stepants, hygrophilous, mesotrophocoenomorphes, endogeic topomorphes. The measured edaphic characteristics have been shown to play an important role in structure of an ecological niche in mesopedobiont community. The basic trends of structure transformation of the animal community of soil mesofauna have been found as soil humidity gradient and edaphic properties variability caused features of a forest vegetation cover. The usage of morphological or physiological features of animals for an estimation of degree of specific distinctions is applicable for homogeneous taxonomic or ecological groups possessing comparable characteristics which also can be interpreted ecologically. The soil mesofauna is characterized by high taxonomic and ecological diversity of forms and comparing which by morphological or physiological criteria it is rather inconvenient. Ecological sense of characteristics in different groups will not be identical, and the basis for their comparison will be inadequate. Therefore we apply to the description of the ecological features ectomorphic analysis of soil animals. The organization of communities of soil animals may be considered at levels of an investigated point, a biogeocenosis, a landscape and regional level. Actually, on the basis of landscape-ecological distribution of species in ecological space their accessory to ecological groups – an ecomorphes is established. Various directions of allocating an ecomorphes at the landscape level conditionally are considered independent and form an ecological matrix (in multidimensional space – a multidimensional matrix, or tensor). As the level of a biogeocenosis correlation degree with the ecomorphes, possibly, will be rather high, therefore soil animals will form local, but functionally significant, groups. The regular ratio of ecomorphes in these functional groups will be a reflection of their organizational structure and an ecological diversity. The obtained data testifies to the justice of the come out assumption. It is important to notice that fact that the functional groups allocated in ecological space by means of the RLQ-analysis, show regular patterns of spatial variability. Local functional groups are characterized by ecological characteristics which reflect in terms one ecomorphes of property of others, occupying the higher hierarchical position. So, it is established that within the studied range, steppe ecomorphes are presented by megatrophic, xerophilous, megatrophocoenomorphes, and mostly phytophagous or predatory forms. Meadow and paludal forms are mainly epigeic (paludal) or anecic (meadow), hygrophilous or ultragygrophilous, saprophagous. The pioneering complex of destructive loci is presented by functional group which has no accurate coenotic status, but gravitates to steppe type. Such result approaches us to an understanding of mechanisms of transformation of community of soil animals under anthropogenic impact. For this purpose it is necessary to return to understanding coenomorphes as indicators of types of circulation of substances and energy flow on A. L. Belgard (1971). In such treatment we observe destruction coenotic system unities of a complex under anthropogenic impact, and the functional group appears at us as situational set of species. Obviously, such treatment is hypothetical and demands the further check. However the considered algorithm of gathering of materials and their statistical processing gives the practical tool for the decision of the given problem.</p> <p><em>Key words: </em>soil mesofauna, ecological niche, spatial ecology, ecomorphes</p>

Modeling the effects of organic nitrogen uptake by plants on the carbon cycling of boreal forest and tundra ecosystems

Abstract. Boreal forest and tundra are the major ecosystems in the northern high latitudes in which a large amount of carbon is stored. These ecosystems are nitrogen-limited due to slow mineralization rate of the soil organic nitrogen. Recently, abundant field studies have found that organic nitrogen is another important nitrogen supply for boreal forest and tundra ecosystems. In this study, we incorporated a mechanism that allowed boreal plants to uptake small molecular amino acids into a process-based biogeochemical model, the Terrestrial Ecosystem Model (TEM), to evaluate the impact of organic nitrogen uptake on ecosystem carbon cycling. The new version of the model was evaluated for both boreal forest and tundra sites. We found that the modeled organic nitrogen uptake accounted for 36–87% of total nitrogen uptake by plants in tundra ecosystems and 26–50% for boreal forests, suggesting that tundra ecosystem might have more relied on the organic form of nitrogen than boreal forests. The simulated monthly gross ecosystem production (GPP) and net ecosystem production (NEP) tended to be larger with the new version of the model since the plant uptake of organic nitrogen alleviated the soil nitrogen limitation especially during the growing season. The sensitivity study indicated that the most important factors controlling the plant uptake of organic nitrogen was the soil amino acid diffusion coefficient (De) in our model, suggesting that the organic nitrogen uptake by plants is likely to be regulated by the edaphic characteristics of diffusion. The model uncertainty due to uncertain parameters associated with organic nitrogen uptake of the tundra ecosystem was larger than the boreal forest ecosystems. This study suggests that considering the organic nitrogen uptake by plants is important to carbon modeling of boreal forest and tundra ecosystems.

Ornamental plants as climatic indicators of arthropod vectors

Abstract The importance and risk of vector-borne diseases (e.g., leishmaniasis, West Nile Virus, Lyme borreliosis) is going to increase in the European temperate areas due to climate change. Our previous studies have shown that the potential distribution of Leishmania infantum and some Phlebotomus (sand fly) species - a parasite of leishmaniasis, and its vectors - may be expanded even to the southern coastline of the Baltic Sea by the end of the 21st century. The lowland areas of the Carpathian Basin and the main part of Hungary are projected to be suitable for the studied sand fly vectors in the near future. It is important to find some indicator plants to examine whether the sand flies are able to live in a certain climate at a certain time. We studied several Mediterranean and Sub-Mediterranean plant species, and we found that the aggregated distribution of three ligneous species (Juniperus oxycedrus L., Quercus ilex L. and Pinus brutia Ten.) shows high correlation with the union distribution of five sand flies (Phlebotomus ariasi Tonn., Ph. neglectus Tonn., Ph. perfiliewi Parrot, Ph. perniciosus Newst. and Ph. tobbi Adler, Theodor et Lourie). Since these Mediterranean species are highly tolerant of the edaphic characteristics of the planting site, they may prove to be good indicators. The present and upcoming climate of Hungary is seen to be suitable for the selected indicator plant species, and it draws attention to and verifies the potential of the expansion of sand flies, which has been proved by some recent observations of the vectors in Southern Hungary.

Influences on the establishment and dominance of vegetation in stormwater infiltration basins

Infiltration basins are widely used in urban environments as a technique for managing and reducing the volume of stormwater. These basins can be spontaneously colonized by wild plants, which can be used as bioindicators of edaphic characteristics. As the basins are anthropogenic environments, the description of plant biodiversity allows the determination of which species colonize such environments and identification of the relationships between plants, basin type and operation. Nineteen infiltration basins were selected according to their catchment types (industrial, urban, agricultural). The dominant species were identified and sampled. Rumex sp., Taraxacum sp. and Artemisia sp. are the three types most represented (88, 61 and 55% respectively of the basins studied). Their families and their respective orders are those most commonly found (Caryophyllales, Asterales and Polygonaceae, Asteraceae). Poaceae is the family grouping with the largest number of different species (11). Although each species occupies only 1 or 2 basins, plants of this family occupy 61% of the basins. Although the catchment characteristics of the 19 basins do not play a direct role in the diversity of plant families, they can influence the presence or absence of certain species. Thus, these plants can be used as bio-indicators of basin soil and operating characteristics, such as sediment depths, inundation frequency and duration.

Environmental effects on distributions of culturable soil oligotrophic bacteria along an elevational gradient in the Chihuahuan Desert

Oligotrophic bacteria have been isolated from many habitats, yet environmental regulation of their distributions in soil has not been elucidated. To address the issue of environmental influence upon oligotrophic distributions, Chihuahuan Desert soils were sampled from five sites along an elevational and vegetational gradient within Big Bend National Park during January and August of 2002 and 2003. Soils were diluted and plated on oligotrophic media, and plates were incubated at 15, 25, 35, 45 and 60 °C. Additionally, measurements of soil organic matter, pH, moisture, extractable nitrate, extractable ammonium and microbial biomass carbon were collected for each sample to relate oligotrophic bacterial distributions to soil nutrient and edaphic characteristics. Analysis of variance indicated significant site, season, incubation-temperature and interaction effects on total oligotroph numbers. Canonical correspondence analysis and multiple regressions indicated that all soil-chemistry variables significantly influenced discrete morphologies of oligotrophs. Oligotroph distributions were most congruent with soil-chemistry variation in three sites, whereas oligotrophic diversity in two sites did not adhere closely to measured environmental variables. While vegetation type may structure oligotroph communities at the two mid-elevational sites, abiotic constraints are drivers in low-desert sites.

Syrian Bean-Caper (Zygophyllum fabago L.) Improves Organic Matter and Other Properties of Mine Wastes Deposits

The omni-presence of Zygophyllum fabago L. (Syrian bean-caper) natural colonies in post mining areas prompted us to investigate its contributions to reclamation of mine wastes deposits′ in southeast Spain. Select plant-related (edaphic) characteristics and bio- and water soluble-Cd, Cu, Pb and Zn in rhizosphere of Z. fabagowere compared to deposits one year since application of pig slurry and marble waste. Total N in rhizosphere increased up to a factor of 20X (339 vs 17 mg N kg−1) in El Gorguel and 27X (85 vs 3.1 mg N kg−1) in El Lirio sites. Organic matter accumulation in rhizosphere from litter and roots of Z. fabagoincreased organic C from 6.6 to 19.5 g kg−1in El Gorguel and from 2.1 to 5.7 g kg−1 in El Lirio in one year. Dissolution of inorganic C takes place due to organic acids from root exudates of Z. fabago. Reduction in bio-available Cd, Cu, Pb, and Zn in rhizosphere of Z. fabagoat El Lirio is attributed to increase in pH from 5.3 to 7.7 through marble waste addition, although increased cation exchange capacity may also have played a role. Addition of marble waste to encourage colonization by Z. fabagoin acidic mine wastes deposits was recommended.

THE SPATIAL ORGANISATION OF THE SOIL MESOPEDOBIONTS UNDER RECREATION IMPACT

In work the results of studying of the spatial organization of soil mesofauna of the artificial forest planting have been processed by OMI- and RLQ-analysis methods. Our research were conducted in June, 6st, 2011 in Oles Gonchar University botanic garden (earlier – territory of park of J. Gagarin, Dnepropetrovsk). The studied plot is situated at a distance of 220 m from the Building 1 of DNU and at a distance of 95 m from Y. Gagarin Avenue (the Southeast direction) (48°25'53.88"С, 35°2'25.82"?). The plot consists of 15 transects directed in a perpendicular manner in relation to the Avenue. Each transect is made of seven sample points. The distance between points is 2 m. The coordinates of the lower left point have been taken as (0; 0). The plot represents artificial forest-park planting. The vegetation has typically wood, mesotrophic and mesophilic character (93.55% – silvants, 70.97% – mesotrophic, 57.84% – mesophiles). At each point the soil mesofauna was studied; temperature, electrical conductivity and soil penetration resistance, dead leaf layer and herbage height were measured. Soil-zoological test area had a size of 25×25 cm. In ecological structure of the soil animal community have been found such groups dominant as saprophages, pratants and stepants, hygrophilous, mesotrophocoenomorphes, endogeic topomorphes. The measured edaphic characteristics have been shown to play an important role in structure of an ecological niche in mesopedobiont community. The basic trends of structure transformation of the animal community of soil mesofauna have been found as soil humidity gradient and edaphic properties variability caused features of a forest vegetation cover. The usage of morphological or physiological features of animals for an estimation of degree of specific distinctions is applicable for homogeneous taxonomic or ecological groups possessing comparable characteristics which also can be interpreted ecologically. The soil mesofauna is characterized by high taxonomic and ecological diversity of forms and comparing which by morphological or physiological criteria it is rather inconvenient. Ecological sense of characteristics in different groups will not be identical, and the basis for their comparison will be inadequate. Therefore we apply to the description of the ecological features ectomorphic analysis of soil animals. The organization of communities of soil animals may be considered at levels of an investigated point, a biogeocenosis, a landscape and regional level. Actually, on the basis of landscape-ecological distribution of species in ecological space their accessory to ecological groups – an ecomorphes is established. Various directions of allocating an ecomorphes at the landscape level conditionally are considered independent and form an ecological matrix (in multidimensional space – a multidimensional matrix, or tensor). As the level of a biogeocenosis correlation degree with the ecomorphes, possibly, will be rather high, therefore soil animals will form local, but functionally significant, groups. The regular ratio of ecomorphes in these functional groups will be a reflection of their organizational structure and an ecological diversity. The obtained data testifies to the justice of the come out assumption. It is important to notice that fact that the functional groups allocated in ecological space by means of the RLQ-analysis, show regular patterns of spatial variability. Local functional groups are characterized by ecological characteristics which reflect in terms one ecomorphes of property of others, occupying the higher hierarchical position. So, it is established that within the studied range, steppe ecomorphes are presented by megatrophic, xerophilous, megatrophocoenomorphes, and mostly phytophagous or predatory forms. Meadow and paludal forms are mainly epigeic (paludal) or anecic (meadow), hygrophilous or ultragygrophilous, saprophagous. The pioneering complex of destructive loci is presented by functional group which has no accurate coenotic status, but gravitates to steppe type. Such result approaches us to an understanding of mechanisms of transformation of community of soil animals under anthropogenic impact. For this purpose it is necessary to return to understanding coenomorphes as indicators of types of circulation of substances and energy flow on A. L. Belgard (1971). In such treatment we observe destruction coenotic system unities of a complex under anthropogenic impact, and the functional group appears at us as situational set of species. Obviously, such treatment is hypothetical and demands the further check. However the considered algorithm of gathering of materials and their statistical processing gives the practical tool for the decision of the given problem.

Dynamics of a Community of Dominant Woody Riparian Species Along a Coastal River of Texas

Abstract Little is known about the structure of riparian communities within the central Gulf coast of Texas. We present a phytosociological description of the riparian corridor within two contiguous sites along the Mission River in Refugio County, Texas, that differ in respect to tidal influence along the river, and compare this woody riparian community to others in Texas. In summer 2009 and 2010, we established 33 transects perpendicular to the river after reviewing digital data from ArcMap 9.3.1 on elevation, edaphic characteristics, uses of land, and cover of land and wetland. We included sites above and below the tidal zone to ensure that the diversity of the community was documented. Transects traversed the edge of the river, ridge and swale topography, and up to the transitional zone between the riparian zone and upland habitat. We sampled a total of 137 plots and documented all species of trees, shrubs, and vines with diameter at breast height ≥3 cm. The important species were Ulmus crassifolia, Ce...

Ecological niche modeling implicates climatic adaptation, competitive exclusion, and niche conservatism among Larrea tridentata cytotypes in North American deserts1,2

Larrea tridentata is a dominant and widespread shrub of North American warm deserts. The species comprises three “chromosomal races,” including diploids (Chihuahuan Desert), tetraploids (Sonoran Desert), hexaploids (Mojave and western Sonoran Deserts), as well as the geographically restricted tetraploid L. tridentata var. arenaria. Creosote bush is a recent arrival to the North American continent, and it is hypothesized that its geographic dispersion reflects rapid ecological divergence mediated by polyploidization. Here we use species distribution modeling to quantitatively evaluate alternate hypotheses for cytotype distributions, based on comprehensive field sampling of creosote bush populations over four years. Using ecological niche models and analyses of field-collected soils, we test whether (1) the climatic niche of the three cytotypes are differentiated; (2) there is evidence for strong climatic gradients at the distributional boundaries of the cytotypes; and (3) cytotype ranges are distinguished by edaphic features. Quantitative tests of niche equivalence indicated that distribution models for all cytotypes were significantly different from one other, suggesting that cytotype races occupy unique and distinctive habitats. However, tests of niche similarity suggest a pattern of niche conservatism, wherein cytotypes tend to occur in climatically similar regions of their respective deserts. Moreover, the modeled diploid distribution was projected to intrude into the geographic range of tetraploids, and the modeled tetraploid distribution was projected to intrude into the range of hexaploids, suggesting that intercytotype competition is a factor influencing cytotype distributions. The range boundary between the dune endemic L. tridentata var. arenaria and hexaploid L. tridentata was noteworthy for exhibiting a strong climatic gradient and striking differences in soil texture (increased sand, decreased gravel). More generally, soil texture differed statistically between sites occupied by diploid, tetraploid, and hexaploid L. tridentata, albeit with considerable overlap across the geographic ranges of the three cytotypes. Taken together, our findings suggest that multiple factors affect the distribution of creosote bush chromosome races, including but not limited to ecological divergence.

Characterization of depth-related changes in bacterial community compositions and functions of a paddy soil profile

Depth-related changes in bacterial community structures and functions were analyzed in a paddy soil profile using denaturing gradient gel electrophoresis (DGGE) and a metabolic profiling technique (BIOLOG ECO plates). Canonical correspondence analysis (CCA) was used to analyze the correlations between the relative abundance of bacterial groups and soil-available elements. DGGE and sequencing analysis revealed 12 classes and one unknown bacterial group. At the family level, Comamonadaceae and Moraxellaceae dominated through the soil profile, while Acidobacteriaceae and Nitrospiraceae dominated in the deepest layer. In addition, Streptococcaceae dominated and was only observed in the deeper layers. Metabolic profiles revealed the greatest carbon source utilization capacity in the surface layer, and no significant differences between upper and deeper soil layers. The carbon sources utilized by microorganisms were different among the different layers. CCA indicated that soil-available Mn, Ca, Cu, Al, and K concentrations were positively correlated with the relative abundance of Comamonadaceae, Moraxellaceae, Streptococcaceae, Microbacteriaceae, Nocardioidaceae, and Nitrospiraceae in the profile. The results showed that the paddy soil profile harbored diverse bacterial communities and experienced depth-related changes in community structure and carbon source utilization. The bacterial communities and functions might be shaped by the soil edaphic characteristics along the soil profile.