We studied the effects of abandonment on two common fen plant species. In mown and a chronosequence of abandoned fen meadows spanning 35 yr, we measured fitness traits of the sedge Carex davalliana and the forb Succisa pratensis. Cessation of mowing had little effect on fitness traits and seed production of C. davalliana, but seedling density decreased more than threefold. Population density of S. pratensis decreased with increasing community biomass, but was not affected by the cessation of mowing. However, flowering frequency increased threefold and seed production was 20% higher in fallow meadows. Consequently, seedling density of S. pratensis increased nearly threefold after abandonment. However, these changes were not dependent on the age of the fallow. In a common garden and germination experiment, we found no differences in either species between plants from fallows and mown fen meadows, except for the height of the flowering stalk of S. pratensis. The combined results from the common garden experiment and the field studies indicate that changes in fitness traits observed in fallows were mostly phenotypic and likely to be reversible. If other species react in similar ways, there is a high potential for re-establishing traditional fen meadow communities from fallows by mowing.

Nomenclature: Binz & Heitz (1990).

We studied the restoration success of flood plain meadows in the northern Upper Rhine valley, where between 1988 and 1992, 35 ha of arable land was converted into grassland and subsequently managed for nature conservation.

Remnant populations of typical alluvial meadow species were found in old meadows and along drainage ditches that dissect the whole area. We analysed the site conditions and phytosociological relevés in old and new meadows. Small differences in site parameters between old and new meadows contrasted with a clear floristic differentiation between the two meadow types. The vegetation of old meadows was much more differentiated along prevailing environmental gradients than the vegetation of new meadows. Despite the favourable site conditions for the re-establishment of species-rich meadows on the former arable land, restoration success was limited to the vicinity of remnant stands. In contrast to old meadows, indicator species of new grassland were still typical species of regularly disturbed ruderal and arable habitats, often capable of building up a persistent seed bank.

The precise mapping of 23 target species revealed that even wind dispersal predominantly leads to re-establishment in the close circumference of parent plants. We found no indication that regular flooding, hay-making and autumnal grazing had an impact on recolonization of newly created grassland. Even under favourable conditions for the re-establishment of target species, restoration success in alluvial meadows proved to be strongly dispersal limited. We discuss the implications of our findings for future restoration management in grasslands.

Nomenclature: Wisskirchen & Haeupler (1998).

The effects of warming on a montane meadow was simulated by a translocation experiment. A coherent piece of turf and soil was transferred from 600 m to 170 m a.s.l., corresponding to an increase in temperature of ca. 2.8 K. The vegetation was monitored by recording cover and counting individuals one year before the translocation and continued for the subsequent seven years. For comparison, a control plot that had also been translocated but remained at 600 m was monitored. Four of eight species with a montane distribution in Europe showed a constant degree of cover during the investigation period (Nardus stricta, Poa chaixii, Polygonatum verticillatum, Potentilla erecta). In contrast, another four montane species declined in cover or died out (Arnica montana, Meum athamanticum, Hypericum maculatum, Galium harcynicum). None of these species declined on the control plot. It is argued that the species' responded individualistically to the site factors that had changed with the translocation to low altitude. A direct effect of enhanced temperature was probably the reason for the decline of only one species (Meum athamanticum). Reduced humidity might be the reason for the extinction of two moisture demanding species (Viola palustris, Succisa pratensis). The biomass of the plot increased by increased growth of one of the matrix species (Festuca rubra), probably due to elevated nutrient mineralization. Many low growing species responded indirectly to the reduced light availability, caused by an increased level of competition for light (e.g. Galium harcynicum). Increased slug herbivory at low altitude resulted in the extinction of Arnica montana. At the end of the investigation period, the similarity in species composition to the initial state was only 45%, indicating that the community had changed into a different plant association. The importance of considering biotic interactions when predicting the impacts of climate change is discussed.

Nomenclature: Phanerogams according to Ehrendorfer (1973); mosses according to Frahm & Frey (1987).

Abbreviations: AFE = Atlas Florae Europaeae; RGR = Relative growth rate.

Winter and spring burnings constitute a traditional management practice of the Flooding Pampa grasslands which are dominated by the tussock grass Paspalum quadrifarium. In addition to increasing the primary productivity and the nutrient quality of the regrowth, this burning favours the establishment of opportunistic species, especially the legume Lotus glaber and the thistles Cirsium vulgare and Carduus acanthoides. The aims of the present study were to assess the effects of burning and those of the remnant litter on L. glaber and thistle recruitment, as well as the effects of L. glaber density on the emergence, survival and flowering of thistles. Two field experiments were carried out: 1. A completely randomized factorial design with occurrence of L. glaber and fire was applied in a mature Paspalum stand; 2. A completely randomized design with four L. glaber seed densities oversown on a burned Paspalum stand, as the treatments. Thistle and L. glaber recruitment within the Paspalum stand was dependent on fire, but their emergence in burnt plots was reduced by the presence of remnant litter. Remnant litter and interference from L. glaber provide complementary mechanisms to reduce fire-cued colonization by thistles. While seedling emergence of thistles was mostly affected by the presence of remnant litter, seedling survival depended on local density of L. glaber. By the end of the first post-fire growing season, the survivorship of established thistles was linearly reduced with increasing sowing density and above-ground biomass of L. glaber. The maintenance of a significant litter coverage and a high density of L. glaber in the pre-fire seed bank, as well as the oversowing of L. glaber after fire, may be useful tools in fire management of Paspalum stands aimed to improve their forage value with reduced dependence on chemical control of weeds.

Nomenclature: Cabrera (1953).

The biodiversity of species-rich semi-natural meadows is declining across Europe due to ceased management. In this study we aimed to find out how successfully the local species richness of an overgrown semi-natural mesic meadow could be restored by sheep grazing after a long period of abandonment. The cover of vascular plant species in grazed plots and ungrazed exclosures was studied for five years and the responses of different functional plant groups were followed (herbs vs grasses, tall vs short species, species differing in flowering time, species representing different Grime's CSR strategies and species indicative of rich vs poor soil). Grazing increased species number by nearly 30%. On grazed plots the litter cover practically disappeared, favouring small herbs such as Rhinanthus minor, Ranunculus acris, Trifolium pratense and the grass Agrostis capillaris. Grazing decreased the cover of the late flowering tall herb Epilobium angustifolium but had no effect on the abundance of the early flowering tall herbs Anthriscus sylvestris or Geranium sylvaticum. We suggest that to succeed in restoration it is useful to determine the responses of different functional plant groups to grazing. Grassland managers need this information to optimize the methods and timing of management used in restoration. Additional management practices, such as mowing, may be needed in mesic meadows to decrease the dominance of tall species. The availability of propagules seemed to restrict further increase of species richness in our study area.

Abbreviations: GRI = Grazing response index; NMDS = Non-metric MultiDimensional Scaling.

Nomenclature: Hämet-Ahti et al. (1998).

Ellenberg's bio-indication system for soil moisture (F), soil nitrogen (N) and soil reaction (R) was examined, based on 559 vegetation samples and environmental characteristics (vegetation cover, soil depth, soil moisture, chemical soil properties) from four Faroe islands. The original indicator values from central Europe were used for the calculation of weighted community indicator values of F, N and R. These were regressed with respect to environmental data, applying standard curvilinear regression and generalized linear modelling (GLM) and new predicted values of community indicator values were obtained from the best model. Faroe species optima values of 162 taxa for one or more of the three Ellenberg scales were derived from fitting Huisman-Olff-Fresco (HOF) models of species abundance with respect to predicted community indicator values and are proposed as new Ellenberg species indicator values to be used in the Faroe Islands. F was best correlated with a GLM model containing soil moisture, organic soil fraction, soil depth and total vegetation cover, R with a GLM model containing pH and calcium in % organic soil fraction, N with total phosphorus in % organic soil fraction. The calibrated species indicator scales are much truncated, as compared with the original values, resulting in significantly different overall distributions of the original and new species indicator values. The recalculated community indicator values are much better correlated to environmental measurements. Several species do not have clear optima, but linear or monotone relationships to the examined indicator scales. This probably indicates that the occurrence of some species in the Faroe Islands are either determined by factors other than moisture, pH or soil nutrient status or, given the young age and environmental instability of the islands, are governed by stochastic mechanisms. Extension of Ellenberg indicator values outside central Europe should always be carefully calibrated by means of adequate environmental data and adequate statistical models, such as HOF models, should be applied.

Nomenclature: Smith (1978); Purvis et al. (1992), Johansen (2000).

Abbreviations: F = Soil moisture, GLM = Generalized linear modelling, HOF = Huisman-Olff-Fresco, LOI = Loss on ignition (organic fraction), MSD = mean soil depth, MSM = mean volumetric soil moisture, N = soil nitrogen, R = soil reaction

Woodland colonization on wetlands is considered to have a detrimental effect on their ecological value, even though detailed analysis of this process is lacking. This paper provides an evaluation of the ecological changes resulting from succession of poor fen (base-poor mire) to willow wet woodland on Goss Moor NNR in Cornwall, UK. Different ages of willow carr were associated with eight understorey communities. During willow colonization, in the ground flora, there was a progressive decrease in poor fen species and an associated increase in woodland species, which appeared to be related to an increase in canopy cover and therefore shade. The most diverse community was found to be the most recent willow and was dominated by poor fen species. The oldest willow was the second most diverse and was associated with a reduction in poor fen species and an increase in woodland species. Architectural features were used successfully to assess the general condition and structure of willow. Tree height and DBH were identified as useful parameters to accurately assess willow age in the field. The implications of active intervention to remove willow in order to conserve the full range of communities within the hydrosere are discussed.

Nomenclature: Stace (1997) and Meikle (1984) for higher plants; Daniels & Eddy (1990) and Smith (1978) for bryophytes.

Vegetation and soil seed banks of a threatened Atlantic fen meadow community were studied using recent phytosociological records and seedling emergence from soil samples. Similarly managed but differently degraded stands that suffered different levels of species impoverishment were compared. The actual vegetation was related to a set of phytosociological references representing the subassociations of the community. DCA positions of reference relevés from the different subassociations were overlapping, suggesting that in all references many common species occur. Recent records were positioned in-between the seed bank samples and the references. The soil seed banks of all stands were dominated by ordinary species. Most character species had at most sparse seed banks and no seedlings of locally extinct character species, mentioned in historic floristic records, were detected. In contrast species of pioneer and small-sedge communities as well as those of heathlands were abundant in the seed banks. Based on the vertical distribution of seeds in the soil layers most fen meadow species were classified into transient or short-term persistent seed bank types. We concluded that complete restoration of the Cirsio dissecti-Molinietum without reintroduction is only likely in stands that were degraded only a few years ago. On the other hand, the presence of viable seeds of Nanocyperion and Parvocaricetea species is promising for the restoration of these communities even after decades. Recreation of pioneer habitats by sod cutting will preserve these species.

Nomenclature: van der Meijden (1996) for taxa; Schaminée et al. (1996) for syntaxa.

Abbreviations: DCA = Detrended Correspondence Analysis; EXV = Eexterveld; ULE = Ule Krite; WYL = Wyldlannen; WTS = Wijnjeterperschar.

The objective of the present study was to map dominant plant communities of an alpine area in the northeastern Alps (Austria), based on computer modelling. We employed gradient analysis by means of Canonical Correspondence Analysis (CCA) as a prediction tool and image segmentation as a filter for reducing the number of incorrect predictions. Topographical variables reflecting relief properties at different scales were used as surrogates for environmental conditions in combination with spectral band values from infrared orthophotographs. Coupling topographic correlation using CCA and image analysis proved practicable to map the distribution of alpine plant communities. Although plant communities often showed similar spectral response, they were mapped according to their specific topographical niches. Generally, topographic variables, indicative of environmental gradients controlling plant distribution, provided this information in most cases. The importance of spectral vs topographic variables varied among plant communities. Whereas the correlation between topography and plant species distribution was particularly significant for mapping alpine grasslands, spectral texture measures proved to be of major importance in discriminating between pioneer communities. Post-processing by image segmentation improved overall accuracy by 12%. A total of 17 plant communities and their mosaics were mapped, with an overall accuracy of 69.4% and a κ value of 0.64. Inaccuracy resulted from insufficient resolution of the available digital elevation model and confounding effects of additional controls like land use history, which could not be accounted for by topographic descriptors.

Abbreviations: CCA = Canonical Correspondence Analysis; DCA = Detrended Correspondence Analysis; DEM = Digital Elevation Model; GIS = Geographic Information System; NDVI = Normalized Difference Vegetation Index.

Nomenclature: Adler et al. (1994).

The effects of different forms of land use on germination and establishment of the rare fen species Succisella inflexa were investigated in seed introduction experiments in a mown and an abandoned fen meadow in SE Germany. Treatments included abandonment, mowing in fall and mowing with creation of gaps in the moss and litter layer. Floating capacity of seeds was tested in order to estimate potential dispersal by water.

On the mown meadow, gaps had a slightly positive effect on germination rates, while greatly increasing seedling survival until the next spring. At the abandoned site, litter inhibited germination, whereas mosses had a negative effect on germination and a positive effect on survival rates during the first year after germination. Both germination and seedling establishment were negatively affected by the presence of slug herbivores. On the abandoned site, no seedlings at all survived until the next spring. Even though seeds of Succisella inflexa were capable to float for several weeks and to germinate thereafter, the situation at the field sites indicates that long-distance dispersal is highly unlikely. Our results showed that not only direct effects of abandonment, such as accumulation of litter, may have led to poor germination and poor seedling establishment of the species. Additionally, indirect consequences of changes in land use, such as higher seedling herbivory by slugs and successional vegetation changes due to abandonment, were important in determining habitat quality and availability of microsites for seedling recruitment. Furthermore, early mowing imposed seed limitation on plant populations.

Nomenclature: Oberdorfer (1994) for vascular plants; Frahm & Frey (1992) for mosses.