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In the lower siliceous uplands of Central Europe, various types of nutrient-poor grasslands are widespread and grow intermingled. These species-rich grasslands, often dominated by taxa of the Festuca ovina aggregate, comprise various phytosociological classes. They are remnants of a historic rural lands - cape and are of conservation importance. Few studies on such grasslands are available and there has been disagreement in assigning them to appropriate habitat types or syntaxa. We investigated such nutrient-poor grasslands in the lower Aar valley (Middle Hesse, Rhenish Massif). We surveyed 104 vegetation plots distributed throughout the valley and identified syntaxa to (sub)association level. We carried out supervised classification combining cluster analysis, a priori assignment to classes based on prevailing diagnostic species, and regional refinement based on phi-value maximisation of the units. As a result, we classified five associations within four classes: Polytricho piliferi-Festucetum tenuifoliae/Galio harcynici-Deschampsietum flexuosae and Festuco rubrae-Genistelletum sagittalis (Calluno- Ulicetea), Jasiono montanae-Festucetum ovinae (Koelerio-Corynephoretea), Gentiano-Koelerietum pyramidatae (Festuco-Brometea) and Arrhenatheretum elatioris (Molinio-Arrhenatheretea). Ecologically, soil acidity (resulting from Ca concentrations of the bedrock) was the main cause of floristic dissimilarity of the grasslands and thus community differentiation. Many stands grew on soils with intermediate pH and showed a peculiar mixture of basiphilous and acidophilous species. We conclude that (i) our approach of supervised classification yields convincing reproducible results when a syntaxonomic system is adapted top-down to a geographically restricted area, (ii) nutrient-poor siliceous grasslands dominated by taxa of the Festuca ovina aggregate can be well assigned to ecologically meaningful syntaxa, and (iii) the nutrient-poor siliceous grasslands of the Lahn-Dill Highlands are of high conservation relevance and in urgent need of protection.
Cryptogams form a large part of dry grassland plant species richness. As a frequently used tool in grassland restoration, hay transfer is known to transfer cryptogam species. This might result in cryptogam stands differing from those achieved by natural succession. To assess hay transfer as a medium for cryptogam restoration, I analysed species composition of cryptogams in the hay of dry grasslands in Southern Germany, how fast they establish, and how fast they colonize adjacent plots. Cryptogam samples from hay showed species combinations similar to those of the mown sites and large shoot numbers to be present in the hay. Even low-growing and rare species were found in the hay. Hay receptor sites showed larger pleurocarpous moss and fruticose lichen patches than comparable sites without hay transfer, indicating earlier arrival of viable diaspores at the receptor sites. For acrocarpous mosses that colonize new sites by spores, no differences in turf size between succession and restoration plots were found. This shows that species transferred by hay have a distinct advantage over species that have to arrive at newly opened sites by natural means, i.e. many years later. The colonization from small restoration sites into adjacent areas without hay transfer proceeds with moderate speeds of about 1 to 2 m per year, probably with wind drift as the most important dispersal agent. Abundant cryptogam species including most pleurocarpous mosses and some Cladonia species rarely producing spores will be greatly enhanced by hay transfer. Nevertheless, the facilitation of pleurocarpous mosses may be detrimental to acrocarpous moss and epigaeic and saxicolous lichen species diversity, which should be considered in dry grassland restoration. I suggest a combination of different restoration measures in a mosaic pattern to create suitable conditions for a maximum of cryptogam species.
Between 1996 and 2006 the vegetation succession in drift sands and in blown-out gravel-rich depressions, located in the nature reserve Hulshorsterzand in the central Netherlands, was studied. Within this Natura 2000 habitat (type 2330: inland dunes with open Corynephorus and Agrostis grasslands) so-called lichen steppes are included, famous for their biodiversity, both in flora (cryptogams), and in fauna. With multivariate analysis, the relation between the primary succession, the species composition of the vegetation and the soil quality was studied in three different biotopes i.e. 1. drift sand, 2. blownout gravel-rich depressions and 3. drift sand after management. With a total of up to 34 species, lichen diversity in the study area appeared to be high. Biotope 1, i.e. the pioneer vegetation with Corynephorus canescens on blowing sand, is rather scarce in lichens. Between 1996 and 2006 green algae, C. canescens and Polytrichum piliferum appeared, with the result that much of the former open drift sand area was covered by pioneer stages of the Spergulo-Corynephoretum. If sand stopped blowing in, a combination of P. piliferum with the neophyte Campylopus introflexus occurred. The terminal stages of lichen succession on drift sand, a vegetation with mainly Festuca ovina s.l., Deschampsia flexuosa and reindeer lichens (Cladonia subgen. Cladina), proved to be rather stable. Since 1996 the lichen steppes occurring in biotope 2 were increasingly grass-encroached. Where some sand was still blowing in, lichen diversity did not change much, but gradually C. introflexus increased. However, without sand blowingin, a decreasing lichen cover and loss of some Red List lichens occurred. In general, in this grass-rich vegetation Calluna vulgaris will germinate and gradually a dry heath might develop. However, where dynamics had stopped and Pinus sylvestris seedlings established, succession to a young forest started. Vegetation change from open sand to lichen-rich vegetation is clearly related to a decrease in pH, an increase in organic matter, in % total N and in % total P. The lichen composition is clearly related to this gradient. The applied restoration measures on steep sand dunes in the eastern area, both of cutting pine trees and removing topsoil down to the mineral soil layer, proved to be successful. The sand kept drifting and the pioneer community thriving, including the lichen Stereocaulon condensatum characteristic of pioneer conditions, while the neophytic moss hardly increased between 1996 and 2006.
We report on the activities of the European Dry Grassland Group (EDGG) during the last year, namely the 8th European Dry Grassland Meeting in Uman', Ukraine in June 2011, the 3rd EDGG Research Expedition in Bulgaria in August 2011, the 4th EDGG Research Expedition in Sicily in April 2012, as well as the completed and forthcoming EDGG-coordinated special features in international journals. Then we provide a brief bibliometrical analysis of the Dry Grassland Special Features in Tuexenia since 2005. The 32 contributions of the years 2005–2011 constituted approx. 17% of the overall content of Tuexenia in this period. Including this 7th Dry Grassland Special Feature, sixty-one authors from 12 countries have contributed to these Special Features, guest-edited by yearly changing teams from a total of 16 guest editors. In the years with statistically reliable data, contributions in the Dry Grassland Special Features have been cited approximately four times as much as regular Tuexenia contributions. It is likely that this fact together with the internationality of the Special Features has contributed to the final inclusion of the journal in the Web of Science in 2011. Finally, we introduce the four research articles of this 7th Dry Grassland Special Feature. Two of them are focusing on vegetation change and restoration issues of cryptogam-rich sand dunes in the Netherlands and calcareous grasslands in Bavaria (Germany), respectively. The others, dealing with siliceous grasslands in Hesse (central Germany) and the results of EDGG Research Expedition 2009 to Transylvania (Romania), focus on syntaxonomy.
The continuous decline in biodiversity in some European landscapes has led recently to the (re-) implementation of low-intensity grazing systems as an alternative to more cost-intensive conservation practices. This approach aims at developing habitat complexes comprising various successional stages and increasing plant species diversity on local (a-diversity) and landscape scales (b-, y-diversity). The primary objectives of this review were to uncover ecological processes in which large domestic herbivores (cattle, equids, sheep, goats, pigs) have a key function in affecting plant diversity and to provide a framework for future research and conservation practices. The reviewed literature covers a wide range of ecosystem types in various temperate regions of Europe with a main focus on recent results from Central Europe. Low-intensity grazing enhances existing environmental gradients and generates manifold disturbance patterns on various spatial scales resulting in high habitat diversity. Livestock trampling has a so far underestimated impact on plant species composition and richness. Additionally, selective herbivore behavior facilitates the coexistence of plant species representing different functional types including a considerable number of threatened and grazing-sensitive species. Co-occurrence of progressive and regressive successional processes on low-intensive pastures results in a high b- and y-diversity, an effect that has been observed soon after the (re-)implementation of grazing. Persistence of speciespoor successional stages of dominant competitive graminoid and herb species can in many cases be inhibited by grazing. Large domestic herbivores serve as effective vectors for the dispersal of diaspores, thus improving the connectivity of isolated plant populations. There is a combined effect of diaspore dispersal and microsite creation which can increase the probability of diaspores to successfully germinate and establish. Overall, low-intensity grazing represents a highly flexible concept to maintain and restore plant diversity in cultivated landscapes; general management implications are given.
We present the results of a unique study of long-term succession in a former raised bog after intensive peat cutting. As probably one of the first restoration experiments the study site "Gammelmose" (22 ha) in NE Zealand, Denmark, was in 1844 protected from any further human usage. Since then several surveys of water level, peat re-growth and vegetation change were carried out in 18 permanent plots. The vegetation data from 1861, 1885, 1963, 1981 and 2005 were analysed with DCA and correlated with selected environmental variables. The peat layer increased in thickness by <1 m within the period 1859–2005, and the bog surface became slightly convex; the water level was at 10–20 cm belowground in 2005. The vegetation developed from an open wetland with a number of fen species over a phase with locally dominant Phragmites australis to a half-open birch-pine forest with abundant Sphagnum-mosses. The increasing frequency of woody species was reflected by lower Ellenberg indicator values for light and soil moisture. The first DCA axis was correlated with succession time and frequency of woody species, and negatively with the two Ellenberg indicator values. The second DCA axis was also correlated with time and woody species, but negatively with Ellenberg values of soil nutrients and soil reaction. In the period 1861–2005, several fen species with relatively high demands for light and nutrients disappeared (e.g. Peucedanum palustre, Stellaria palustris, Viola palustris), while most bog species continued (e.g. Andromeda polifolia, Vaccinium oxycoccos, V. uliginosum), and new plant species – mainly naturalised from gardens – immigrated (e.g. Spiraea alba var. latifolia, Picea glauca, Prunus padus). In 2005, the vitality and growth of many trees in the bog looked reduced, and some of the taller individuals began to sink into the peat layer. Thus, in future the half-open bog forest may show some natural dynamics allowing survival of bog species in a mosaic of changing microhabitats.
Bramble scrubs are among the least known and understood vegetation types in Europe. In the Dutch National Vegetation Overview, three associations belonging to the Lonicero-Rubion silvatici were distinguished, viz. the Rubetum grati, Rubetum silvatici, and Rubetum pedemontani. During several vegetation mapping projects and Rubus excursions, a distinct type of bramble scrub was recorded repeatedly in the Campine in the province Noord-Brabant in the southern part of the Netherlands. In this paper, this scrub is described as a new association, the Rubetum taxandriae Haveman, de Ronde & Weeda, with R. taxandriae, R. campaniensis, and R. baronicus as character species, and R. insectifolius as regional character species. Variation, ecology and distribution of this new association are given and discussed, and two subassociations are distinguished. The differences with the Rubetum silvatici, to which this community was believed to belong, are discussed. Based on an earlier analysis of the centres of diversity of the genus Rubus in the Netherlands, it is supposed that the Rubetum silvatici in its circumscription in the Dutch National Vegetation Overview can be divided in more regionally distributed communities, partly as subassociations of the Rubetum silvatici, partly as independent associations.
In the Westphalian Basin (North-Rhine Westphalia, Germany), 176 relevés of hedgerows first surveyed during the 1970s were reassessed in 2009 and 2010, and the floristic differences between these two time points were compared. The results were used to analyse the impact of exogenous factors on the species community composition using multivariate statistics (non-metric multidimensional scaling). Significant changes were found within all of the communities along the first axis of the ordination, and, in most cases, increasing average temperatures were best correlated with these alterations. However, based on the considerable evidence found, the alterations induced by land-use change and the intensification of agriculture appear to be the inducing factors.
This paper explores political engagement by Guatemalans who seasonally migrate to Canada as contracted agricultural workers. Since 2003, an ever-increasing number of Guatemalans have pursued economic opportunities in Canadian fields and greenhouses as participants in a labour migration scheme brokered by the International Organization for Migration (IOM) called the Temporary Agricultural Workers to Canada (TAWC) Project. While some describe this labour migration as a win-win situation for employers and migrant workers, for too many of these migrants, work in Canada has demanded sacrifices and losses, not the least of which of their human rights and dignity at the hands of employers and administrators of the TAWC Project. While there is a great deal at stake for these migrants should they denounce mistreatment, given the climate of fear created by the employer-driven nature of the TAWC project, a growing number of them have been pushed to do so. With the support of allies that encourage political empowerment of migrant workers, black-listed Guatemalans have formed a political advocacy group - Asociación de Guatemaltecos Unidos por Nuestros Derechos (AGUND) - aimed at fighting for the realization of their rights and redressing cases of wrongdoing. Based on workers’ testimonies and other institutional interviews, this paper outlines the difficulties workers have experienced as labour migrants to Canada, the context of vulnerability that largely impedes them from denouncing mistreatment, and the development and activities of AGUND. Informed by literature on political organizing, it also identifies the factors that have both impeded and encouraged political activity on the part of these disenfranchised yet determined Guatemalan workers.
The European Union is currently challenged by right-wing populism and economic stress. To understand the nature of these challenges, we need to take an interdisciplinary approach in which empirical studies of politics are combined with studies of the normative implications of European policy-making. To this end, I draw attention to the right to free movement, which is pivotal both for European politics and liberal political philosophy. I show that even though transnational rights, such as the free movement for people, products and money, are normatively sound and desirable, enhancement of free movement may challenge the heterogeneity among the national models of rights and societal commitments. The risk is that the national institutions as a political arena face difficulties in coping with current political challenges such as right-wing radicalism, social inequality, environmental regulation, immigration and financial insecurity. On the other hand, I argue that we should be aware that the transnational rights might in some countries enhance human rights, which national parliaments have not been able to accommodate.