Long-Term Changes in Spatial Patterns and Life-Stage Structure in a Population of Senecio umbrosus Waldst. et Kit. Along With the Transformation of Grassland Vegetation (original) (raw)
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Acta Societatis Botanicorum Poloniae, 2011
The study aimed to determine the long-term changes of the Senecio macrophyllus M.BIEB. population traits: the abundance, reproduction mode, individual fecundity, seed rain and recruitment of new genets in the course of xerothermic grassland overgrowing. The study had also the applied goal: to estimate the chances of special care species to survive in the changing environment without management regime for the maintenance of grassland. The model object was the island population of large-leaved ragwort on Bia³a Góra (the White Mountain) near Tomaszów Lubelski, SouthEast Poland. To achieve these aims I used the following sets of data: phytosociological relevés made in plant communities in an interval of 16-18 years; repeated elaboration of the numbers and life-stage structure of the population, both by non-surface and surface method; observation of plants life cycle in 50 labelled genets; population reproduction and seed rain amounts. The area of an open xerothermic grassland decreased due to the process of overgrowing by bushes which was accompanied by the increasing coverage of forest and meadow herbs as well as monocotyledons, mainly Brachypodium pinnatum and Calamagrostis epigejos. The abundance of the S. macrophyllus population noticable diminished. The flowering mode has been changing during years from an oscillation to a chaotic type which caused the significant decreasing of the individual fecundity, population reproduction and seed rain. In last years it was reflected in the interruption of juveniles recruitment.
Past land use co-determines the present distribution of dry grassland plant species. -Preslia 80: 183-198. Landscapes are constantly changing and, for plant species, this means that some suitable patches disappear while others emerge. Distribution of species in the landscape depends, therefore, not only on actual distribution of suitable habitat patches but also on a species' ability to persist in habitats that are already unsuitable and disperse to habitats that have become suitable. Distribution of species in such landscapes thus strongly depends on the spatio-temporal structure of the landscape and species traits. The present study aims to determine to what degree past land use affects the present distribution of dry grassland plant species at a regional scale. We studied the distribution of 52 dry grassland species in 215 grassland patches. Data on bedrock, slope, potential irradiation, area and past land use for two periods (1950s and 1980s) were collected from maps. Multivariate analysis was performed to assess the relative contribution of environmental and historical factors on present species distribution. In addition, analyses were carried out to reveal the relationship between past land use and occurrence of single species. This study shows that dry grasslands are habitats with rapid land-use changes. Distribution of species in these habitats is largely determined by environmental conditions, but past land-use also has a significant effect. In many species, the effect of past land use is even more important than the effect of environmental conditions. For the species investigated, those restricted both to former pastures and fields could be identified. Only a minority of species are restricted to continuous grasslands. This indicates that many species colonized places cultivated in 1950 within 50 years, suggesting that the dynamics of these species is relatively fast. The results suggest that many dry grassland communities in the region are of recent origin and the distribution of species in these habitats is partly determined by past land use. In addition to information on environmental conditions, detailed knowledge of land use history, landscape structure and species attributes is needed in order to understand the distribution of species in dry grassland communities.
Successional changes of dry grasslands in southwestern Slovakia after 46 years of abandonment
Plant Biosystems - An International Journal Dealing with all Aspects of Plant Biology, 2011
Dry grasslands are endangered by succession because of changes in management, soil conditions and abandonment. The successional changes in vegetation composition after 46 years of abandonment were subject of the study. The analyses were designed to minimize errors that could be caused by application of historical data. With the help of numerical classification, internal variation within the associations was evaluated. Using computer modeling in GIS, the suitable management model for dry grasslands was defined. The following impact of successional changes was observed: The cover of expansive woody species Crataegus sp., Prunus sp., Rosa sp.; non-native species Pinus nigra, Prunus serotina, Robinia pseudoacacia, Syringa vulgaris, Fraxinus ornus, and competitively strong species Bromus erectus, Calamagrostis epigejos, and Peucedanum cervaria increased. The covers of non-native species represent 29% of the total forested area. The Poo badensis-Festucetum pallentis communities are the most endangered. The species diversity, cover of Festuco-Brometea species and Red List species decreased significantly in this vegetation type. The area of grasslands has been reduced by 61.1% compared with 1949 levels. We defined the ''core'' zone with the highest abiotic potential for the conservation of the xerothermophilous communities, where their long-term occurrence will not depend on the presence of the management interventions.
Vegetation-environment relationships in grassland communities of central Slovakia
A systematic survey of grassland communities in central Slovakian sub-montane and montane regions (including the Kremnické vrchy Mts., Starohorské vrchy Mts., Veľká Fatra Mts., and Zvolenská kotlina Basin) was performed between 1996 and 2007. The main aim was to identify main environmental gradients in the studied vegetation and to estimate the most important individual variables responsible for the variation of their species composition. Along with the floristic composition, the environmental variables were either recorded in the field (altitude, slope, aspect), calculated (solar radiation, climatic data, and phytochorological affinity), or derived from available maps or GIS digital data layers (type of bedrock, soil parameters). These environmental variables were used as supplementary in the detrended correspondence analysis (DCA) or explanatory in the canonical correspondence analysis (CCA). The affiliation of individual phytosociological relevés to associations was estimated by an electronic expert system for Slovak grassland communities. Altogether, 15 xero-, sub-xero-and mesophilous grassland associations were distinguished. Wet and fen meadows were analysed at the level of alliances. Unconstrained ordination revealed moisture and nutrient gradients as most important for the data set. By means of constrained ordination, the variability of the studied vegetation could be explained by a set of geological, topographic, phytochorological and derived climatic variables, although the percentage of explained variance was rather low and did not exceed 12% for all significant factors combined. Among individual variables, the geological bedrock type, climatic water balance, solar radiation, and slope played the most important role in determining the distribution and variability of individual grassland communities. Affinity to phytochorions determined according to local air temperature gradients was also significant. Soil properties played only a subordinate role in our analyses. The analysis of a more homogeneous subset of the data without wetland relevés gave similar results as the analysis of the complete data set. The differences in results of constrained and unconstrained ordinations are discussed together with the potential reasons for extremely high proportion of unexplained variance revealed by the variation partitioning methods.
Community Ecology, 2008
Significant transformation of agriculture took place in Central Europe during the second half of the 20 th century. The paper reviews the nature and consequences of this process in terms of grassland management and land use changes in the Liptov region (N Slovakia) and their impacts on plant communities of fen meadows (Caricion davallianae, Caricion fuscae), wet meadows (Calthion) and mesophilous grasslands (Arrhenatherion, Cynosurion). We studied in detail the changes in structure of the rare plant community Trollio-Cirsietum (Kühn 1937) Oberd. 1957 that occurred between the first period (1974-1983) and the second period (2002-2003). We recorded the decrease in abundance of species characteristic for permanently wet and fen meadows (alliances Calthion and Caricion davallianae) and the increase in abundance of characteristic species of seasonally dried, mesophilous and thermophilous meadows and mesophilous fringes (classes Molinio-Arrhenatheretea, Festuco-Brometea and alliances Molinion caeruleae, Bromion erecti and Trifolion medii). In the second studied period, a large group of mesophilous and thermophilous species appeared as new in this wet-meadow community. A cumulative impact of different factors, especially drainage and intensification of surrounding grasslands as well as abandonment of the community can represent reasons responsible for observed changes. Regardless identified changes, the community still maintains its typical character in significant proportion of the studied sites and hosts a high number of threatened plant species.
1 Distribution of plant species in fragmented landscapes is the result of both seed and site availability. Little is known about how their relative importance differs at different spatial scales. 2 I sowed seeds of eight dry grassland species into 22 localities that differed in occupancy by these species and followed seedling establishment over 3 years. I compared the number of emerging seedlings at three scales: between previously occupied and previously unoccupied localities, between occupied and unoccupied blocks within occupied localities, and between plots with and without seed addition within occupied blocks. 3 At the two larger scales, I also studied the relationship of the number of seedlings and of the distributions of adult plants to environmental factors. 4 Both seed and site availability are important in structuring the distribution of these species, but site availability becomes less important with increasing spatial scale. The intensity of this effect is, however, species specific. 5 The relationship between environmental factors and pattern of species distribution is also clearly scale dependent, and differs between seedlings and adults. Whilst abiotic factors are the main determinants of seedling distribution, the occurrence of adult individuals is best predicted by the occurrence of other species. This suggests that the present distribution of species in the landscape is determined mainly by historical factors. 6 Conclusions based on the importance of seed and site availability for species distribution in natural communities at one scale cannot be extrapolated to other scales. Only comparisons on multiple scales can provide a full understanding of factors affecting species distribution at landscape level.
Tuexenia, 2009
We first report from the 5 th Dry Grassland Meeting held from 28 th to 30 st of August 2008 in Kiel, Germany. Then we take stock of the achievements of the German Arbeitsgruppe Trockenrasen and the international Working Group on Dry Grasslands in the Nordic and Baltic Region towards establishment of vegetation databases of dry grasslands in these study regions. At the conference, the European Dry Grassland Group (EDGG) was founded as an international platform of dry grassland researchers and conservationists. As networking tools it provides a homepage on the internet, publishes a quarterly electronical bulletin, and will organise the future European Dry Grassland Meetings. In the last part of this contribution, we give a short introduction to the five articles of this Special Feature. Four of them make a major contribution to supra-national classification of Koelerio-Corynephoretea and Festuco-Brometea communities, respectively, by providing syntaxonomic overviews based on comprehensive data from eastern European countries for which only few data have been available until now. The other major focus of the Feature papers is on degradation and restoration of various types of dry grasslands. Zusammenfassung: Trockenrasen im Wandel-Sammelbeitrag mit Artikeln von der 5. Trockenrasentagung 2008 in Kiel Zunächst berichten wir von der 5. Trockenrasentagung vom 28.-30. August 2008 in Kiel. Dann fassen wir zusammen, was die deutsche Arbeitsgruppe Trockenrasen und die internationale Working Group on Dry Grasslands in the Nordic and Baltic Region hinsichtlich der Errichtung von Datenbanken mit Vegetationsaufnahmen von Trockenrasen aus den jeweiligen Untersuchungsgebieten bislang erreicht haben. Während der Tagung wurde die European Dry Grassland Group (EDGG) als internationale Plattform für Trockenrasenforscher und-schützer gegründet. Sie will zum Informationsaustausch zwischen diesen beitragen, indem sie eine Homepage im Internet betreibt, ein vierteljährliches elektronisches Bulletin publiziert und die künftigen European Dry Grassland Meetings organisiert. Im letzten Teil führen wir kurz in die fünf Artikel dieses Sammelbeitrages ein. Vier davon stellen einen wesentlichen Beitrag zur großräumigen Klassifikation der Koelerio-Corynephoretea bzw. Festuco-Brometea dar, indem sie syntaxonomische Übersichten basierend auf umfangreichem Aufnahmematerial aus osteuropäischen Ländern präsentieren, für die bisher kaum pflanzensoziologische Daten verfügbar waren. Der zweite Themenschwerpunkt in den Artikeln ist die Degradierung und Wiederherstellung von verschiedenen Trockenrasentypen.
Plant Ecology, 2014
Fennoscandian calcareous wooded meadows have high conservation value due to very high diversity which has been maintained by consistent mowing, but undergo species loss when this management is abandoned. We compared species richness and composition of regularly mown and abandoned wooded meadows in Estonia and established species groups with respect to their response to abandonment. These meadows were very species rich with a maximum of 43 species per 0.25 m 2. Species whose populations are maintained by mowing constituted [60 % of the floristic diversity of the mown wooded meadows. Abandonment suppressed species with a preference for dry infertile open habitats. Response to abandonment was related to clonality, height and growth form. The greatest negative response was associated with low graminoids, short-lived and nonclonal species, rosette and semi-rosette growth form. Weak competitors with low height and light seeds exhibited a slow decline; perennial life span and clonality enable a delay in local extinction of these species. Response groups had similar persistence at a national level, revealing that earlier assessment of species dynamics at larger spatial scales could underestimate the number of threatened species. Application of restoration measures could avoid local extinctions of many mowing-supported species, whereas some of the mowing-dependent species likely need reintroduction.
Agriculture, Ecosystems & Environment, 2014
According to island biogeography theory, the species richness of patches is determined by their size and spatial isolation, while in conservation practice, it is patch quality that determines protection and guides management. We analysed whether size, isolation or habitat quality are most important for the species richness in a set of 50 dry grassland fragments in agricultural landscapes of eastern Austria. We studied two plant taxa (vascular plants, bryophytes) and 11 invertebrate taxa (gastropods, spiders, springtails, grasshoppers, true bugs, leafhoppers and planthoppers, ground beetles, rove beetles, butterflies and burnets, ants and wild bees). The species richness of three categories was analysed: (1) dry grassland specialist species, (2) all grassland species and (3) all species. We used regression and hierarchical partitioning techniques to determine the relationship between species richness and environmental variables describing patch size and shape, patch quality, landscape configuration and landscape quality. The area-isolation paradigm was only applicable for dry grassland specialists, which comprised 12% of all species. Richness of all grassland species was determined mostly by landscape heterogeneity parameters. Total species richness was highly influenced by spillover from adjacent biotopes, and was significantly determined by the percentage of arable land bordering the patches. When analysing all taxa together, species richness of dry grassland specialists was significantly related to historical patch size but not to current patch size, indicating an extinction debt. At the landscape scale, the variable 'short-grass area' was a better predictor than the less specific variable 'area of extensively used landscape elements'. 'Distance to mainland' was a good predictor for specialists of mobile animal taxa. Plant specialists showed a pronounced dependence on quality measures at the patch scale and at the landscape scale, whereas animal specialists were influenced by patch size, patch quality, landscape quality and isolation measures. None ଝ This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial-No Derivative Works License, which permits noncommercial use, distribution, and reproduction in any medium, provided the original author and source are credited. et al. / Agriculture, Ecosystems and Environment 182 (2014) 25-36