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Non-forest woody vegetation (scattered greenery) is currently a common feature of the rural European landscape and provides important ecosystem services. This study presents the statistically based classification of non-forest woody vegetation at the local level according to its structural characteristics mapped in the field. Using hierarchical agglomerative cluster analysis, four groups (clusters) of non-forest woody vegetation were detected. Relation of groups of non-forest woody vegetation to altitude, slope gradient and distance from settlements was found, although differences in these factors between groups are small. Moreover, differences in spatial structure in terms of landscape ecology among groups of non-forest woody vegetation were examined and considerable differences among groups were recognized when comparing basic landscape metrics. Presented classification covers unique local or sub-regional groups of non-forest woody vegetation, but it is not sufficient for the national level. For this purpose, it is advocate advised that additional data be collected and official evidence of existing non-forest woody vegetation be generated.
Given the finite resources of seed production, a trade-off between seed weight and number was expected. However, it still remains unclear how the seed weight-number trade-off changes if there are some mechanisms to enhance resource acquirements during the fruit developments. Sinopodophyllum hexandrum presents furled leaves in flowering time but unfurled leaves in fruiting time, which is considered to enhance the photosynthates to fruit development. To determine the relationship between seed weight and number of S. hexandrum, we examined the altitudinal variations and the relationship between seed weight and number in the fruits from 27 populations of in 2009 and 2010. Our results showed that, along the altitudinal gradient, seed weight decreased significantly but seed number increased insignificantly, indicating that the selective pressure on seed production might come from seed dispersal in high altitude populations. There was no significant relationship between seed weight and number in most populations, but an inverse relationship was found between seed weight and number when the data from all populations were pooled, indicating the seed weight-number trade-off and resource limitation of seed production in S. hexandrum on species level. We suggested that the two unfurled leaves of S. hexandrum might contribute to the resources allocated to the fruit development via enhancing photosynthates, which might mask the seed weight-number trade-off on population level to some degree.
In arid and semi-arid ecosystems, shrubs have an important effect on neighboring plants. However, little is known about the interaction of herb growth stages and shrub location on herb performance. We selected Reaumuria soongorica, (Pall.) Maxim a shrub dominant in the semiarid region of northwest China, to determine whether (1) shrubs facilitate or have negative effects on neighbouring herbaceous vegetation, and (2) such effects vary with herb growth stage and with shrub orientation relative to herbs. The presence of herbaceous plant species, plant density, plant height, and percent cover were determined along 2 m long transects spreading in four directions from the base of shrub — east (transect E), west (transect W), south (transect S), and north (transect N); this was repeated for three growth stages (in May, June and July). Results indicated that the effects of R. soongorica on neighboring herbs in different growth stages were similar. Species number of herb-layer plants tended to increase from beneath the canopy to the opening, but plant density, cover and plant height decreased with distance away from shrub base. The presence of R. soongorica had positive effects on density, cover, and plant height, and negative on the number of herbaceous species during the entire growing season. Herbaceous plants growing on transect N under the shrub canopy had significantly higher density and percent cover than those growing in other directions. Biomass of herbs on transect N grown under the shrub canopy was higher than that of herbs on other transects. We concluded that shrub effects on neighbouring herbaceous vegetation were closely related to the shrub orientation relative to the herbs. Therefore, using shrubs as nurse plants for grass-growing must consider the relative placement of shrubs.
Primary producers are able to strongly affect calcium budget in hardwater lakes. The relative contribution of phytoplankton and charophytes to water decalcification (by precipitation of calcium carbonate) is, however, unclear. In this study we checked the effect of natural phytoplankton community and a charophyte (Nitellopsisobtusa) on the decline of calcium concentration in experimental outdoor conditions. The experiment was carried out in original lake water and two variants of enrichment with inorganic nitrogen and phosphorus to test the changing efficiency in decalcification by both primary producers. At low nutrient concentrations, N. obtusa was responsible for calcium decline in original lake water by 12 mg Ca 2 dm-3 during 20 days of experiment. In these conditions the effect of phytoplankton was negligible. In lake water enriched with nutrients, the exponential growth of phytoplankton led to the decrease of calcium concentration from initial 35 mg Ca 2 dm-3 to 9 mg Ca 2 dm-3 in the same time period. The maximum effect of N. obtusa was the same as in original lake water but manifested itself earlier to decline in the end of experiment. Supersaturation of water with calcium carbonate was always more than threefold and saturation index reached 27 in mixed cultures of phytoplankton and N. obtusa in lake water enriched with nutrients. In this context we hypothesise on a possible role of charophytes as nucleation sites necessary for calcite precipitation. Based on our own and literature data we also discuss expected immobilisation of phosphate incorporated in calcite precipitated by the growth of phytoplankton and N. obtusa.
Biodiversity is of crucial importance for ecosystem health and functioning. It is thus one of the most important topics in forest ecology. This study focuses on modelling the spatial distribution of vascular plant diversity (H), richness (S) and evenness (E) in the Yukarıgökdere forest district (14667 ha) located in transition zone between Mediterranean and continental climates in the Mediterranean region, Turkey. Species abundance was sampled at 95 sample plots extending from 1000 to 1900 m a.s.l. in order to calculate the response variables (H, S, E). Climatic and topographical data served as explanatory variables. Multiple regression (ML) and classification and regression tree technique (CART) were used to obtain the distribution models of response variables. The better results were provided by CART. That is why visual assessments of the predicted values of the response variables based on (CART) were performed. The explained variances of the model trees were 63.4, 63.1 and 44.5% for H, S and E respectively. Elevation was found to be the most important environmental factor for all response variables. The higher H and S values were found at the east lower part (1000–1150 m a.s.l.) and the west upper part (1500–1800 m a.s.l.) of the district. The evenness (E) shows generally higher relative values in the upper part of the area. The lowest E specifies the area being optimal for tree growing. It is located between 1400 and 1500 m a.s.l., and ranges from the north to the south in the district.
Our research was conducted on abandoned fields which had been undergoing spontaneous succession for 40–50 years and then were partly burnt. The main objective of the study was to examine if spontaneous fire in the early successional stage of pine forest causes a decrease in the number of species, diversity and density of seed banks, and an increase in the share of species forming long term persistent seed banks. Standing vegetation and soil seed banks were studied on 20 permanent plots on adjacent burnt and unburnt sites one and twelve years after spontaneous fire. One year after the fire the number of species in the seed banks of both areas was similar (11 and 12 species). In the burnt area the Shannon index and the floristical similarity between the seed bank and standing vegetation were lower, and seed density five times higher than in the unburnt area (15 691.5 m-2vs.3426.5 m-2). This was mainly the effect of the high number of seedlings of Callunavulgaris (L.) Hull and Spergula morisonii Boreau germinating from the burnt plots. Twelve years after the fire the number of species in both seed banks had increased little, but seed density in the burnt area (1742.5 m-2) had decreased 16 times, while that of the unburnt area had changed only slightly (2875.5 m-2). At the same time the Shannon index for the burnt area increased considerably whereas, for the unburnt one it did not change. Our study shows that the long-term persistent soil seed bank plays a fundamental role at the beginning of the post-fire regeneration of temperate coniferous forest vegetation. Germination of Calluna seedlings from the burnt soil seed banks in several times higher numbers than from unburnt soil seed banks may suggest that heat from the fire promotes a loss of dormancy in the heather seeds.
The objective of research was to verify, whether succesion of nudal beech forests affects energy, ash and Ct contents of top layers of cambisols and aboveground part of dominant herb species Dryopteris filix-mas. The forest stands, from the juvenile stemwood to the stand of primeval forest character, were located in Slovenské stredohorie Mts (Western Carpathians). It has been found out that the successional stages of beech stands significantly affected soil characteristics of the ecotope, in the case of Dryopteris filix-mas species significant difference was observed only for the energy content. Approximately 7.5% less energy was accumulated in humus subhorizons Oof of mature beech stands (110, 200 years) compared with the juvenile stemwoods. On the other hand, in Aoq horizons markedly more energy (by 35–66%) was accumulated in the soils of mature beech phytocoenoses. The influence of stand succession differentiated ash content in Aoq horizons too. Significant difference (7.6%) was found between 85 and 200-year-old beech stand. Within studied parameters only accumulation of Ct in top soil layers was not significantly affected by stand succession. The relation between energy and ash accumulation in top soil layers of studied beech stands showed significant correlations between the variables (P <0.01). Approximately 62% of energy variability in humus subhorizons Ool of the studied stands was affected by the ash content (lower was the ash content — higher was the energy content). In Aoq soil horizons this dependence was 50% (higher was the ash content — lower was the energy content).
Physiological and ecological adaptations of altitudinal gradients reveal alpine plants' ecological and evolutionary responses to environmental changes. Here we quantitatively investigated the variation in the foliar physiological and morphological traits of alpine tree species (Abies fargesii) along the altitudinal gradient in the Taibai Mountains, China. We collected the needle samples of Taibai fir (A. fargesii) from seven sites at altitudes of 2550, 2650, 2750, 2850, 2950, 3050 and 3150 m, respectively, and measured the 12 foliar physiological and morphological traits. Each set of needle sample (100 needles) was randomly selected from the upper- third of A. fargesii canopies.
The results showed that leaf mass per unit area (LMA), stable carbon isotope composition (δ13C), stomatal rows (SR), leaf carbon concentration per unit area (Carea), leaf nitrogen concentration per unit leaf mass (Nmass) and area (Narea) linearly increase significantly while stomatal density (SD), number of stomata per unit nitrogen concentration (St/N) and per unit leaf mass (St/LM) decrease with the altitudes raise. Moreover, all measured traits presented both strong correlations and significantly linear relationships with the main climate factors such as the mean temperature, rainfall and relative humidity during the growing season as well as the altitudes, except for leaf free water concentration (LWC), leaf carbon concentration per unit leaf mass (Cmass) and C: N ratio.
The patterns of foliar traits in response to altitudes imply that the alpine plants need higher cost (e.g. higher nutrient concentration) to adapt to the harsher environments along altitudinal gradient. Moreover, our results show that the variation patterns of the leaf traits for A. fargesii plants should be driven by the interactions of multi-climate factors because the abiotic factors that directly influence the growth of plants covary with the increasing altitudes.
The ongoing warming in the Qinghai-Tibetan Plateau leads to changes in ecosystem processes while the responses of soil and vegetation are not well understand. Thus, we used infrared radiators to carry out experimental warming from July 2010 to August 2011 in an alpine meadow on the Plateau (about 4630 m above sea level) to research the responses of environmental factors and vegetation characteristics to short-term warming (1 year). The experimental design was a block design consisting of five replications and included three treatment levels: control, T1 (130 W m-2) and T2 (150 W m-2). The results showed that air temperature at 20 cm height, surface temperature and soil temperature in the 0–100 cm layers increased with warming. The biggest differences of T1 (1.66°C) and T2 (2.34 °C) appeared on the surface and at 20 cm depth, whereas the biggest amplitudes of T1 (27.15%) and T2 (35.81%) all occurred at 100 cm depth. Soil moisture showed different trends with warming in different soil layers. In the 0–40 cm layers, soil moisture decreased with warming. The biggest differences (-2.97% for T1 and -2.73% for T2) and amplitudes (-18.07% for T1 and -16.64% for T2) all appeared at 10 cm depth. In the 60–100 cm layers, soil moisture increased with warming. The biggest differences (2.53% for T1 and 6.45% for T2) and amplitudes (11.39% for T1 and 29.05% for T2) all occurred at 100 cm depth. Relative to control, vegetation height and aboveground biomass increased significantly in T1 and T2 (P <0.05), while vegetation coverage had not significant differences in T1 and T2 (P> 0.05). In T1 and T2, the amplitudes were 30.67% and 30.19% for vegetation height, and 36.22% and 27.87% for vegetation aboveground biomass, and 12.89% and 4.42% for vegetation coverage, respectively. In the path analysis between environment and vegetation properties, vegetation was directly affected by soil moisture at 40 cm and 60 cm depths, whereas indirectly influenced by relative humidity at 20 cm height and soil temperature at 40 cm depth. This might be related to the downward movement of the soil moisture caused by warming.
The spread of species far from their native range is an important component of global changes. Investigating the ability of alien plants to invade different habitats is one of the most important approaches in the analysis of biological invasion mechanisms.
The study was based on floristic research carried out in 1998–2002 in the north-western part of Poland. The habitats sampled were classified according to the EUNIS classification. A dataset of 2638 naturalized neophyte records was compiled based on a total of 2132 floristic lists. Species entries were supplemented with data on taxonomic position (family), origin, frequency, life form and number of habitats a particular species colonises. Ordination analyses showed the level of disturbance in individual habitats to be important in species-habitats relationships. Some of the species (e.g. Chamomilla suaveolens, Galinsoga parviflora, Veronica persica) occurred mainly in man-made, heavily disturbed habitats, while others (e.g. Impatiens parviflora, Padus serotina, Quercus rubra) were present primarily in natural habitats, less affected by humans. The species with the broadest habitat ranges identified included, i.a. Conyza canadensis, Impatiens parviflora, Epilobium ciliatum, and Oxalis fontana. Most of them, however, had different “core” habitats. Some species, e.g. Juncus tenuis, Elodea canadensis, Veronica persica were associated with one or a few habitats. The ability of species to invade numerous habitat types did not depend on their invasive status. The most successful aliens are those which spread dynamically along forest paths as well as those penetrating forest communities. The phytocoenotic role of each naturalized neophyte in plant communities requires a detailed study.
Each individual habitat supports well-established alien species whose traits fit its characteristics and the disturbance intensity. Analysis of alien species traits, local distribution, habitat preferences and range makes it possible to reliably assess potentially successful invaders.
This paper outlines the Phytoplankton Multimetric for Polish Lakes (PMPL) — an ecological status assessment method which can be used to implement the European Water Framework Directive (EC, 2000). The PMPL includes abundance parameters of phytoplankton: the metrics: “chlorophyll a”, “total biomass” while the taxonomic composition is partly evaluated by the metric “biomass of cyanobacteria”. All of these three single metrics as well as the final PMPL index values are the same scale and range from 0 to 5. The PMPL can be transformed to a normalized Ecological Quality Ratio (EQR) range from 0 (the worst status) to 1 (the best status). The PMPL method differentiates “stratified” and “unstratified” lake types as well as subdivisions into lakes characterized by a high (>2) or low (<2) lake volume-to-catchment area ratio (VQ). The metrics used and the PMPL index respond to eutrophication pressure expressed by total phosphorus and total nitrogen concentration, the significance of the relationships depends on the tested parameter and the abiotic type of lake. From among the single metrics, the metric “chlorophyll a” was usually found to reveal the strongest significant correlation to both total phosphorus and total nitrogen (Spearman`s coefficient varied from -0.41 to -0.75 and from -0.34 to -0.56, respectively). The weakest correlation with nutrients was noted for metric “biomass of cyanobacteria” (R=-0.13 to -0.62). The PMPL correlated best with TP and TN in unstratified lakes (R=-0.49 to -0.70). The testing of the PMPL index shows a statistically important distinction between Good/Moderate ecological status and confirmed designated boundaries of High/Good and Good/Moderate states.
KEYWORDS: ecological potential, Heavily Modified Water Bodies (HMWB), Macrophyte Biological Index for Lakes (IBML), macrophytes, reservoirs, Water Framework Directive (WFD)
According to the requirements of the European Water Framework Directive, the Member States of the European Union are obliged to assess and report on the ecological potential of heavily modified and artificial water bodies; water reservoirs on rivers were also designated among them. The objective of this study was to gain more knowledge about macrophyte assemblages in reservoirs in Slovakia, where it was necessary to start analyses leading to the ecological assessment. The research was carried out in 14 multipurpose reservoirs during the vegetation seasons 2008–2010. Analyses focused on the determination of species composition considering the similarity between reservoirs, the impact of selected environmental variables on species composition and evaluation of the Macrophyte Biological Index for Lakes (IBML) in relation to its use for ecological assessment. In total, 60 taxa of macrophytes were identified. More than 90% of all determined taxa are indicators of IBML. The statistical analysis performed was based on the study of macrophyte assemblages and environmental variables and gave the following results: i) based on species composition, two main clusters of reservoirs were identified respecting altitude (reservoirs at an altitude above and less than 300 m a.s.l.) and affiliation to phytogeographical ecoregion (reservoirs in Pannonian lowland and Carpathians); ii) water temperature, followed by dissolved oxygen and chemical oxygen demand, were found to be the main environmental variables influencing the composition of macrophyte assemblages using DCA analysis. Water temperature and phosphates were determined to be the variables responsible for species composition using CCA analysis; iii) differences of the mean IBML values between clusters corresponded with the results of cluster analysis. A significant correlation was found between IBML and two variables: conductivity and alkalinity. Based on the results, it is recommended to use the IBML for analyses leading to the assessment of ecological potential based on biological quality elements.
A study on the response of macroinvertebrate assemblages to the restoration of hydrological connectivity of an oxbow lake through the channel excavation is presented. The study included a five-year environmental monitoring (hydrological, hydro-chemical measurements and invertebrate sampling) carried out in the years 2008–2009 and 2011–2012 in the floodplain of the Słupia River (N Poland). The results allowed for assessing ecological effects of the hydrotechnical treatments (re-opening of an old river bed, declogging and installation of wooden deflectors) applied in the oxbow restoration. The results confirmed the preliminary hypothesis that the level of hydrological connectivity determines the dynamics of invertebrate fauna communities in river-floodplain systems. Analysis of the data revealed that such reconnection considerably influenced the structure of hydrobionts by altering abiotic habitat conditions. Effects of radical changes in the habitat morphology and hydrodynamic conditions and monitoring of macroinvertebrate assemblages preformed in the restored lake indicated a significant instability of the ecosystem soon after the treatment, what was confirmed by the results of canonical analysis, in which 50% of the total variance remained unexplained. Among factors analysed, water quality parameters explained 21.4% of the total variance in macroinvertebrate communities. However, the hydrobionts showed a significant instability with respect to variable hydrological conditions (flow through the lake) what contributed to a low share of water flow along the oxbow in explaining the total variance. The analysis of long-term changes that occurred in the studied ecosystem showed that the restoration of full hydrological connectivity brought only a short-term increase in benthofauna abundance. The most distinct reorganization in the structure of macroinvertebrate communities was observed in the first year after the reconnection while the consecutive four years brought only insignificant changes, mainly the appearance of a few species, mainly molluscs. Our investigation suggests that the taxonomic composition of macroinvertebrates in the studied oxbow lake having the only one-arm opening, before the improvement of hydrological connectivity, seemed to be more stable and optimal for this kind of habitat, than after the hydrotechnical works, when the ecosystem became passable due to both-arms connections to the river channel. Therefore, semi-lotic oxbows, connected to parent rivers only with one arm, can be properly functioning aquatic ecosystems in river floodplains.
The study investigated the effect of microhabitat (emergent/submerged macrophytes) within lakes of different status (transparent/cloudy water) on the diversity and distribution of chironomid assemblages. Field and laboratory studies were undertaken bimonthly, from January to November 2008, in two shallow lakes of Polesie Lubelskie (eastern Poland), transparent water and cloudy water lake. The main objectives of the study were to compare the density and taxonomic richness of chironomids associated with emergent and submerged macrophytes within lakes of extremely different environmental conditions and to recognize the most important variables affected chironomid distribution between microhabitats within lakes. In transparent water lake, number of chironomid taxa varied between 12 (emergent macrophytes) and 18 taxa (submerged macrophytes) and was significantly higher than in cloudy water lake, 6 and 8 taxa, respectively. Mean abundance of chironomids associated with emergent macrophytes was higher in cloudy water lake. The opposite relation was observed on submerged macrophytes. The PCA analysis showed visible distinction of chironomid assemblages between microhabitats and lake types. The results of RDA led to determine the significant variables (Monte-Carlo permutation test) affected chironomid distribution. In both, transparent and cloudy water lake, the significant variables responsible for chironomids distinction between microhabitats were density and biomass of macrophytes, biomass of periphytic algae and pH. Moreover, nutrients, N-NO3 (transparent water lake) and P-PO4 (cloudy water lake), showed the significant influence.
Currently, the alternative forms of management are increasingly applied in agriculture. Although their less negative impact on environment is generally supposed, there is still a lack of a reliable data about their real favourability for the abundance and diversity of soil invertebrates, including millipedes. Therefore, the aim of our study was to find out, whether the form of agricultural management affects the structure of millipede communities and hence, the performance of their functions in soil ecosystems. The research was carried out using pitfall trapping through growing seasons 2005 to 2007 on the model territory of Agricultural Cooperative (AC) Očová (Central Slovakia). Millipedes were captured at four pairs of sites (8 sites in total). The same cultivated crop (wheat, barley, alfalfa or permanent law) with application of two different forms of agricultural management (conventional form and sustainable form with basic sustainable agro-environmental scheme) was characteristic of each pair of sites. The research results disclosed that the management form plays a significant role, especially in such agrocoenoses, in which the same crop is cultivated for several years (e.g. sites with alfalfa or permanent lawn), i.e., on the sites without ploughing or other similar agrotechnical measures. In these cases, the sites with the sustainable agro-environmental scheme had higher species richness (8 and 9 species) and higher total abundance of millipede communities (2.2 and 5.7 ind. collected per one day and one trap) than the sites with the conventional form of agrotechnical management (5 and 5 species, 0.09 and 0.3 ind. collected per one day and one trap). In order to obtain a more detailed knowledge about the impact of agricultural management forms on millipede communities, this kind of research should be carried out in different conditions (other crops, soil conditions, climate zones, etc.) as well.
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