Application of remote sensing data for monitoring eutrophication of floodplain water bodies

The aim of this article was to investigate the influence of structural features of the floodplain water network on the spatial and temporal dynamics of chlorophyll-a concentration as an indicator of eutrophication. The research was conducted in the waters of the “Dnipro-Orilskiy” Nature Reserve. The geographic information base with polygonal objects which represented water bodies of the reserve was created on the basis of detailed geographical maps and the high resolution space images. The water bodies were characterized using such parameters as the distance of the water body centroid from the nearest shore of the Dnipro River, the area of the water body, the order of the water body and the connectivity of the water body. Chlorophyll-а concentration was estimated based on the surface algal bloom index. The information was obtained about 148 water bodies, 141 of which are water bodies in the floodplain of the Dnipro River. The area of floodplain water bodies within the reserve was 3.28 million m2. The area of floodplain water bodies ranged from 300–232,500 m2. Trophic State Index allows us to estimate the trophic level of Dnipro River waters as mesotrophic, water bodies of first and second order as eutrophic, and water bodies of third and fourth order as hypereutrophic. The dynamics of chlorophyll-a content in water followed the seasonal course of temperatures. The concentration was lowest in the cold period of the year and reached its maximum in the second half of summer. The autumn decrease occurred at the end of September. The seasonal course of air temperature was superimposed on the peculiarities of the temperature regime of a particular water body, which depended on its depth and flow rate. The time, water body area, distance from the Dnipro River channel, connectivity and order of water bodies were the statistically significant predictors of chlorophyll concentration in water and were able to explain 85% of the variation of this indicator. The increase in chlorophyll-a concentration with increasing order of a water body is due to a decrease in the intensity of water exchange and a decrease in the depth of water bodies of higher order. An increase in the order of a water body is accompanied by a branching network of water bodies, the ability of water bodies to clear sediments decreases. Sediment accumulation leads to a decrease in their depth. Warming of shallow ponds and accumulation of organic matter in them are factors of intensive growth of blue-green algae. The evacuation of surplus organic matter, which results from mass vegetation development with excessive nutrient inputs, is a key driver of the eutrophic regime of water bodies. The increasing importance of regulatory processes develops in agreement with an increase in chlorophyll-a concentration in a water body. The importance of the considered factors reaches the highest level in summer time, when simultaneous maximum warming of water bodies and minimum water level in them take place. Accordingly, the differences between deep and relatively cool water bodies and shallow water bodies that warm up quickly, which significantly stimulates the growth of organic mass, reach the greatest contrast. The spatial patterns of variation in chlorophyll-a concentration have a complex multiscale structure, indicating the multiple nature of the acting factors. The spatial variability was represented as a composition of broad-scale and medium-scale spatial processes. The broad-scale process is most dependent on connectivity, whereas for the medium-scale process the leading one is the effect of water body order

The importance of relief for explaining the diversity of the floodplain and terrace soil cover in the Dnipro River valley: The case of the protected area within the Dnipro-Orylskiy Nature Reserve

Floodplains are centers of species diversity, so floodplain habitats often contain protected areas. However, conservation strategies pay little attention to soils, on which the functional stability of both individual ecosystems and landscape chains as a whole depends. Soil morphology provides structural and functional information about floodplain ecosystems. The spatial and temporal heterogeneity of soil morphology is a cost-effective ecological indicator that can be easily integrated into rapid assessment protocols for floodplain and riverine ecosystem restoration projects. Therefore, the aim of our work was to consider the morphological features of soils of the Dnipro-Orylskiy Nature Reserve and assess the role of soil diversity as a factor of structural and functional sustainability of ecosystems of the protected area, as well as to identify the significance of geomorphological predictors for differentiation of soil types to create a soil map of the territory. The World Reference Base for Soil Resources reference soil groups were classified using geomorphological predictors. Soil types were able to explain 90% of the variation in elevation occupied by soils. Arenosols occupied a statistically significantly higher position in topography than other soil types. In turn, Eutric Arenosols occupied a higher position (68.91 ± 0.48 m) than Eutric Lamellic Arenosols (63.32 ± 0.54 m). Other soils occupied positions in the topography that were not statistically significantly different in height. Soil types were able to explain 38% of the variation in elevation that the soils occupied. The highest Topography Wetness Index values were found for Fluvisols (12.73 ± 0.23) and Solonetz (13.06 ± 0.28 m). Differences between these soils were not statistically significant. Topography Wetness Index was slightly lower for Cambisols (11.80 ± 0.21) and Eutric Lamellic Arenosols (12.21 ± 0.28), which also did not differ on this measure. The lowest Topography Wetness Index value was found for Gleysols (11.15 ± 0.17) and Eutric Arenosols (10.95 ± 0.24), which did not differ from each other on this index. Eutric Arenosols and Eutric Lamellic Arenosols are formed at great depths of the water table (7.89 ± 0.50 and 2.62 ± 0.46 m, respectively). Gleysol and Solonetz form at close groundwater level to the surface (0.28 ± 0.27 and 0.21 ± 0.46 m, respectively) compared to Fluvisol and Cambisol (0.46 ± 0.38 and 0.41 ± 0.35 m, respectively). Elevation was the most informatively valuable predictor, but Topography Wetness Index and Vertical Distance to Channel Network significantly improved discrimination. Arenosols were very different from other soils which occupy an automorphic position. Cambisols occupied a transitional position. Other soils occupied hydromorphic positions. Fluvisols and Solonetz occupied wetter positions, while Gleysol occupied less wet positions. Fluvisols and Solonetz differed in the groundwater table. Solonetz predominantly occurred at close groundwater levels. The classification matrix confirmed the possibility of using geomorphological predictors to build a model of spatial variation of soils in the study area. The spatial model demonstrates the organization of the soil cover of the reserve. Calculations showed that Cambiosols occupy 20.7% of the area, Eutric Arenosols occupy 16.0%, Eutric Lamellic Arenosols occupy 17.9%, Fluvisols occupy 15.2%, Gleysols occupy 28.7%, and Solonetz occupy 1.5%

Anthropogenic load іs a leading factor in the morphological variability of Chondrula tridens (Gastropoda, Enidae) in the northwestern Azov Sea region

Morphometric data are widely used in biology to assess intraspecific and inter-population variability and for bioindication and environmental condition assessment. The following hypotheses have been experimentally tested in the paper: 1) the vegetation type affects the change in the shell shape of Chondrula tridens martynovi Gural-Sverlova & Gural, 2010; 2) the change in the shell shape of this species is influenced by the biotope moisture regime; 3) the shell shape changes depending on the anthropogenic load level. The material in the form of empty, fully formed Ch. tridens shells was collected in 2019 in the north-western Azov region within the basin of the Molochna River. The collection points were located in settlements and outside them and differed in vegetation, moisture regime and level of anthropogenic load. The vegetation has been expertly attributed to two alternative types: herbaceous vegetation and tree plantations. By moisture level, the locations have been assessed as xerophytic and mesoxerophytic. The anthropogenic load levels have been assessed as low, medium and high. The study revealed that the morphological characteristics of Ch. tridens demonstrate a significant component of variability, which is due to the shell size. The shell size depends on the anthropogenic impact level. Under conditions of high anthropogenic impact, the shell size increases. Mollusks from locations with low and medium anthropogenic impact levels did not differ in shell size. After extraction of the size component, morphological properties develop three main trends of variability. The mouth apparatus development of mollusks does not depend on the vegetation type, but depends on the biotope moisture level and the anthropogenic transformation level. The mollusk shell elongation was observed to have the opposite dynamics of the height parameters in relation to the width and depended on the level of anthropogenic load. Rearrangement in the mouth apparatus depended on the biotope moisture level and the anthropogenic load level. There were distinguished four clusters, the quantitative morphological features of which allowed us to identify them as morphotypes. Each location was characterized by a combination of different morphotypes, according to which the sampling points may be classified. Morphotype 1 corresponds to biotopes with low level of anthropogenic load, morphotype 4 corresponded to biotopes with high anthropogenic load. Morphotypes 2 and 3 corresponded to moderate level of anthropogenic load. Vegetation type is not an important factor in determining the morphotypic diversity of populations. Under xerophytic conditions, morphotypes 2 and 3 are more common, and under mesoxerophytic conditions, morphotypes 1 and 4 are more common. The range of molluscs in different habitats needs to be expanded in the future to clarify climatic and other patterns

Diversity of diversity indices: Which diversity measure is better?

The article evaluates the dependence of the most common indices of species diversity on sample size and determines their ability to differentiate between different types of ecosystems, with a special emphasis on discriminating between natural and anthropogenic ecosystems. An approach to adjusting the indices to reduce their dependence on sample size was also proposed. The study was conducted in seven types of ecosystems: four were natural and three were anthropogenically transformed. Samples of soil animals were selected in 2011–2013 and 2021 using the same methods. A total of 20,518 soil animal specimens belonging to 202 species were collected in all study locations. The null alternative was generated by randomly selecting samples containing 2, 3, ..., 110 soil animals from the combined soil animal sample. For each gradation of sample size, 200 sample variants were formed. The density of soil macrofauna in natural ecosystems ranged from 3.6 ± 1.5 to 15.2 ± 6.9 specimens per sample, and in artificial ecosystems – from 13.2 ± 7.6 to 21.0 ± 11.9 specimens per sample. The number of species ranged from 22–80 species, and in artificial ecosystems it was 38–99 species. Indicators of species diversity correlated with each other. A high level of correlation was observed between indicators within groups of indices: indices of species richness and indices of heterogeneity and evenness. Fisher’s log-series alpha and the fundamental parameter of biodiversity were highly correlated with each other, as well as with the Margalef, species richness, and Chao’s species abundance indices. The log-normal distribution best describes the dominance patterns in terms of abundance in the natural ecosystems, and the Zipf-Mandelbrot distribution best describes the dominance patterns in terms of abundance in the artificial ecosystems. Diversity indices were ordered in the space of two dimensions, one explaining the variation between ecosystems and the other depending on sample size. The ordering of the traditional indices showed that there is a vacancy for the best index in the sense that such an index should best explain differences between ecosystems and differences between natural and artificial ecosystems. It should also be independent of sample size. The Simpson heterogeneity index and the Simpson evenness index were the best of the traditional indices, but they did not explain differences between ecosystems very well, especially when it came to distinguishing between natural and artificial ecosystems. The Margalef index, which is supposed to be independent of sample size, on the other hand, showed a very high level of dependence. Such a dependence was also found for the Menhinick index, though to a lesser extent. Obviously, size dependence negatively affects the differential ability of the indices. The corrected indices of species richness and the Shannon index are practically independent of sample size and have a greater ability to differentiate ecosystems by the level of diversity, with natural ecosystems characterized by consistently higher values of the corrected indices than artificial ecosystems. The dependence on the sample size makes indices from different ecosystems practically incomparable, which makes their use meaningless. Even minor differences in sample size can lead to significant deviations in the values of diversity indices. The application of the Michaelis-Menten model allowed us to suggest a method of correction of species richness indices and the Shannon index. After the correction, the indices are practically independent of the sample size, and their differential ability to characterize individual ecosystems and the level of anthropogenic transformation increases significantly

The small-scale variation of herb-layer community structure in a riparian mixed forest

The ground vegetation layer is the most diverse plant community in forest ecosystems. We have shown the role of spatial variables, soil properties and overstorey structure in spatial variation of the herb-layer community in a riparian mixed forest . The research was conducted in the "Dnipro-Orils’kiy" Nature Reserve (Ukraine). The research polygon was located in the forest in the floodplain of the River Protich, which is a left tributary of the River Dnipro. Plant abundance was quantified by measuring cover within an experimental polygon. The experimental polygon consisted of 7 transects, each comprising 15 test points. The distance between the rows in the site was 3 m. At the site we established a plot of 45 × 21 m, with 105 subplots of 3 × 3 m organized in a regular grid. A list of vascular plant species was composed for each 3 × 3 m subplot along with visual estimates of species cover projection. The plant community was represented by 43 species, of which 18.6% were phanerophytes, 39.5% were hemicryptophytes, 9.3% were therophytes, 7.0% were geophytes. An overall test of random labelling revealed the total nonrandom distribution of the tree stems within the site. The species-specific test of random labelling showed the nonrandom segregated distribution of Acer tataricum, Pyrus communis, Quercus robur, and Ulmus laevis. Crataegus monogyna and Euonymus europaeus were distributed randomly. The nearest neighbour of Acer tataricum was less likely to be Ulmus laevis. There was no direct spatial connection between Acer tataricum and other trees. Crataegus monogyna, Pyrus communis, Quercus robur and Euonymus europaeus were not segregated from all other species. The nearest neighbour of Ulmus laevis was less likely to be Acer tataricum. Constrained correspondence analysis (CCA) was applied as ordination approach. The forward selection procedure allowed us to select 6 soil variables which explain 28.3% of the herb-layer community variability. The list of the important soil variables includes soil mechanical impedance (at the depth 0–5, 30–35, 75–80, and 95–10 cm), soil moisture, and soil bulk density. The variation explained by pure spatial variables accounted for 11.0 %. The majority of the tree-distance structured variation in plant community composition was broad-scaled. The spatial scalograms were left-skewed asymmetric. Significant relationship was found between the pure spatial component of the community variation and a number of phytoindicator estimations, most important of which were the variability of damping and humidity. Tree stand was obseerved to be a considerable factor structuring both the herb-layer community and spatial variation of the physical properties of soil

Phytoindication assessment of the effect of reconstruction on the light regime of an urban park

The ecological restoration of urban parks is used to increase their recreational attractiveness, improve air quality, mitigate urban heat island effects, improve stormwater infiltration, and provide other social and environmental benefits. The dynamics of plant communities after urban forest restoration requires investigation. The study assessed the impact of urban park reconstruction on the state of grass cover, phytoindication of changes in light regime caused by park reconstruction and found out the dependence of reliability of phytoindication assessment on the number of species in the relevant area. The study was conducted in the recreational area of the Botanical Garden of the Oles Honchar Dnipro National University (Ukraine). A tree plantation was created after the Second World War in the location of a natural oak forest. In 2019, a 2.8 ha area of the park was reconstructed. The samples were taken within polygons, two of which were placed in the reconstruction area and two of which were placed in a similar section of the park where no reconstruction was performed. During the reconstruction process, walkways were rebuilt, shrubs were removed, old, damaged trees were removed, and tree crowns were trimmed. Juvenile trees were planted in place of the removed old trees. Old outbuildings, which greatly impaired the aesthetic perception of the park, were also removed. Transport and construction machinery was involved in the reconstruction. A total of 65 plant species were found within the studied polygons. The number of herbaceous species in the park area after reconstruction was higher than without reconstruction. The crown closure in the reconstructed area was significantly lower than that in the untreated conditions. The phytoindication assessment showed that the light regime varies from the conditions suitable for the scyophytes (plants of typical foliage forests) to the conditions suitable for the sub-heliophytes (plants of light forests and shrubberies, or high herbaceous communities; lower layers are in the shade). The light regime in the park area after reconstruction was statistically significantly different from the regime in the untreated park area. The lighting regime after the reconstruction was favourable to sub-heliophytes, and without reconstruction the regime favoured hemi-scyophytes. Tree canopy crown closure negatively correlated with grass height and herbaceous layer projective cover. The tree canopy crown closure, grass height, and herbaceous layer projective cover were able to explain 86% of the phytoindication assessment of the lighting regime variation. These parameters negatively affected the light regime. The prospect of further research is to investigate the dependence of indicative reliability of the assessment of other environmental factors with the help of phytoindication depending on the number of species. In addition to the indication of traditional ecological factors it is of particular interest to clarify the aspect of the dynamics of hemeroby indicators as a result of park reconstruction

The role of ecological groups in the formation of cyanobacterial communities in the ecosystems of the North Azov region (Ukraine)

The role of Cyanoprokaryota ecological groups in the ecosystems of the North Azov region was revealed in this work. On the territory of Pryazovskyi National Nature Park, 9 experimental polygons were studied, which covered steppe areas or slopes, salt marshes, coastal sandy soils and water bodies (rivers, lakes, estuaries, sea bays, lagoons). As a result of research on the territory of Pryazovskyi National Nature Park, 124 species of cyanoprokaryotes were identified, which include 127 intraspecific taxa. It was proved that the procedure of canonical correspondence analysis is the most suitable for the analysis of the species matrix. The axes identified as a result of the ordination procedure, which indicate the coordinated dynamics of the species, correlated with both synecological characteristics, such as diversity indicators, and with autoecological characteristics, such as ecotypes of cyanoprokaryotes in relation to habitat types or types of adaptation to salinity conditions. The first four canonical axes together explain 47.5% of species matrix variability. Canonical axis 1 explains 18.0% of the variability of the species matrix and is mostly marked by aqual subaerophytes and eurybionts. This axis indicates the presence of a gradient of salinity conditions where the most saline conditions correspond to the positive values of the axis, and the negative values correspond to less saline. Canonical axis 2 describes 12.1% of species matrix variability. This axis differentiates aquatic ecosystems from others. Canonical axis 3 explains 10.0% of the communities’ variability. This axis distinguishes freshwater ecosystems from saline ecosystems. Markers of freshwater communities are stenotopic halotolerants, which are narrow-range, common mainly in the temperate zone of Europe. The canonical axis 4 explains 7.3% of variability of the matrix of species and is able to differentiate sand ecosystems. The ecotopic structure and geographic range width of community species have the greatest independent value among the considered sources of variation. The independent role of adaptation to the salinity conditions of the ecotope and the role of the type of ecosystems is somewhat smaller. The interaction between the sources of variation is important in the variation of the structure of communities. The interaction between the ecotopic structure and the geographic range width of species and the triple interaction between the ecotopic structure of a community, the width of the geographic range of species and the ecosystem type plays the greatest role in the variation of community structure. Ecotopic groups, which indicate the preference of a particular habitat, correlate with the species composition of the communities. It is shown that the ratio of ecototopic groups in a community is a characteristic that reveals the features of the community as a whole

Ecological Niche Packing and Spatial Organisation of the Urban Park Macrofauna Comminity

Abstract. The results of studying of the spatial organization of the soil macrofauna of the urbanozem of the grassland were processed by OMI- and RLQ-analysis methods. The biogeocenotical situation at the location of an experimental polygon was shown to be typical of a meadow-steppe mega-mesotrophic xeromesophic character. The data for the research was collected by means of manual sorting of the soil samples with the area of 0.25×25 cm on a regular grid (7×15 samples) with the distance between the selection points 2 m (results presented as L-table), the measurement of temperature, electrical conductivity and soil penetration resistance, the litter depth and the height of the grass (R-table). The soil macrofauna of the experimental area was represented by 27 species with a total density of 56.38 ind./м2. The ecological structure of the animal community of the soil was dominated by the pratants and silvants, mesophiles, olygotropic, endogeic topomorphs, saprophagous. Such edaphic characteristics as soil penetration resistance, electrical conductivity, litter depth, as well as height of grass, played an important role in structuring of ecological niche of macrofauna community. The first two axis of OMI analysis described 73.43% of inertia, which was sufficient for the description of the differentiation ecological niches of macrofauna on the investigated polygon to conduct in the space of the first two axes. For the average value of the marginality of the community (OMI = 2.90), the significance level was р = 0.001, which testifies to the important role of the selected environment variables for structuring of the soil macrofauna community. The four key functional groups of macrofauna were found as a result, the RLQ-analysis and the next cluster procedure and assessed the role of the edaphic factors in their spatial variation. Each of the functional groups was interpreted in terms of an ecomorphic approach

Modeling the spatial variation of urban park ecological properties using remote sensing data

Parks perform a wide range of ecosystem services in urban environments. The functional importance of parks depends on the composition and structure of the tree stand and the specific influence on soil and microclimatic conditions. The article reveals the dependence of soil and microclimatic properties on the structure of the crown space of a park stand. Spectral indices were also shown to be applicable for predicting the spatial variability of soil and climatic properties and indicators of crown space. Soil properties (temperature, moisture, and electrical conductivity in the 5–7 cm layer) and microclimatic parameters (light exposure, air temperature, and atmospheric humidity) were measured in the park plantation using a quasi-regular grid. The canopy structure and gap light transmission indices were extracted from the true-colour fisheye photographs. Thirty species of trees and shrubs were detected in the stand and understory. Robinia pseudoacacia L. was found most frequently (24.5% of all tree records). Acer negundo L. and A. platanoides L. were also frequent (12.4% and 15.5%, respectively). The first four principal components, whose eigenvalues exceeded unity, were extracted by the principal components analysis of the variability of ecological properties and vegetation indices. The principal component 1 explained 50.5% of the variation of the traits and positively correlated with the spectral vegetation indices. The principal component 1 reflected the variability of tree cover densities due to the edaphic trophicity. The principal component 2 described 13% of the variation in the feature space. This component correlated positively with the spectral indices. The principal component 2 was interpreted as a trend of vegetation cover variability induced by moisture variation. The principal component 3 described 8.6% of trait variation. It was most strongly correlated with the atmospheric humidity. An increase in atmospheric humidity was associated with an increase in the soil moisture and electrical conductivity and a decrease in the soil and atmospheric temperature. The principal component 4 described 7.5 % of the variation of traits. An increase in the values of principal component 4 was associated with an increase in the soil moisture and electrical conductivity and atmospheric moisture and was associated with a decrease in the soil and atmospheric temperature. The combinations of the trophotope and hygrotope create the optimal conditions for specific tree species, which is a condition for achieving the maximization of ecosystem services. The mineral nutrition conditions of plants and soil moisture exhibit spatial patterns that allow them to be considered in the design and management of park plantations. The ecological indices measured in the field were shown to be predicted using the vegetation indices. Multiple regression models were able to explain 11–61% of indicator variation. The regression relationships between markers of soil and microclimatic conditions and vegetation predictors are important for monitoring the condition of park plantations and evaluating the performance of park plantation management tools

Temporal dynamic of the phylogenetic diversity of the bird community of agricultural lands in Ukrainian steppe drylands

This study discussed the importance of the phylogenetic components in the structure of bird communities of anthropogenically transformed ecosystems. The investigation was conducted in the landscapes of the south and south-east of Ukraine in the nesting seasons 1988–2018. The bird community in the agricultural landscape was found to be presented by 10 species. The number of species was closely correlated with its phylogenetic analogue – Faith’s index. Both indices were stationary over time, as they do not show a statistically significant time trend. The two axes were extracted as a result of the DPCOA procedure and the permutation test showed their statistical significance. The axis 1 was the most sensitive to the opposite dynamics of the abundance of Coturnix coturnix and Burhinus oedicnemus on the one hand and Alauda arvensis and Melanocorypha calandra on the other. The axis 2 is the most sensitive to the opposite dynamics of Corvus monedula and Melanocorypha calandra on the one hand and Coturnix coturnix and Motacilla flava on the other. Based on phylogenetic diversity, the years can be clustered with the extraction of four relatively homogeneous phylogenetic structures of bird communities. The indicator of the initial period of dynamics (1988–1992) was Burhinus oedicnemus. Sowing or mechanical weeding may be considered as a major factor of nest destruction of Burhinus oedicnemus. The decreasing of the abundance of the trophic recourses because of agricultural activity may have caused the monotonous negative trend over time of the Burhinus oedicnemus populations. The period 1993–2003 was a transitional one, for which there were no clear indicators, as a characteristic feature of this period was the processes of bird community restructuring. The period 2004–2013 was characterized by the loss of Burhinus oedicnemus from the community and a sharp increase in the abundance of Corvus monedula. These species are distinguished by their phylogenetic specificity and are located on the periphery relative to the phylogenetic core of the community. There was growing importance in the community of such species as Alauda arvensis, Anthus campestris, and Melanocorypha calandra between 2014 and 2018. Our results also confirm the assumption that phylogenetic overdispersion is an important requirement for the stability of the bird community in anthropogenically transformed landscapes