A spatio-temporal variation of vegetation during spontaneous succession was studied in 56 basalt quarries spread over 1800 km² in the České středohoří Hills (NW Czech Republic, Central Europe). Differences in the particular habitats inside a quarry, i.e. steep rocky slopes, bottoms and levels; dumps; and screes were considered. The habitats ranged in age from 1 to 78 yr since abandonment. Macroclimate (mean annual temperature and precipitation) significantly influenced the course of succession, which led to a formation of shrubby grassland, shrubby woodland or tall woodland. Participation of target species typical of steppe-like communities significantly depended on the occurrence of the communities in the vicinity, up to a distance of 30 m from a quarry. Disused quarries may become refugia for rare plant species. Spontaneous successional processes led in the reasonable time of ca. 20 yr to semi-natural vegetation. Thus, they can be successfully exploited in restoration programs scheduled for the disused quarries.

Nomenclature: Hennekens (1995) for taxa; Oberdorfer (1992) for syntaxa.

Germination experiments were conducted in a heathland after turf cutting and in a climate chamber to investigate the effects of turf cutting depth, aluminium toxicity and aluminium detoxification by humic acids and base cations on the germination and establishment of Arnica montana. Turfs were cut at three different depths, creating a gradient from organic to mineral soils. Germination and establishment of A. montana were negatively correlated with turf cutting depth. The removal of organic matter resulted in a major decrease in organic fraction of the soil and its nutrients. It also resulted in a considerable decrease in moisture content and humic acids. Additional liming after turf cutting increased germination and establishment in all plots and at all depths.

Germination experiments under controlled conditions in a climate chamber revealed a significantly higher germination at low aluminium/calcium (Al:Ca) ratios. High Al:Ca ratios resulted in poor germination, suggesting Al toxicity. Addition of humic acids increased germination, even at high Al:Ca ratios, suggesting immobilization of Al by humic acids.

It is concluded that turf cutting can have a marked effect on the success of heathland restoration. It results in the intended removal of the eutrophic layer but also in the unintentional removal of much of the buffering mechanisms and/or Al immobilizing compounds. Additional buffering and/or less deep turf cutting may be necessary to allow germination and establishment of rare herbaceous species such as A. montana.

Abbreviations: DOC = Dissolved organic carbon; GLM = General Linear Model; ICP = Inductive coupled plasma emission spectrophotometer.

The results of previous studies concerning spontaneous vegetation succession in various man-made or disturbed habitats in Central Europe are discussed in relation to restoration ecology. An attempt is made to answer the main questions which are important to restoration programs. These concern the rate and direction of succession; participation of target species and communities, woody species, ruderals and aliens; arresting or diverting succession; changes in species diversity; variability of successional pathways and the role of abiotic environmental conditions. The great potential for using successional theory in restoration programs is emphasized.

Nomenclature: Kubát et al. (2002).

In previous studies, limited dispersal was revealed to be the main obstacle to restoration of species-rich flood-meadows along the northern Upper Rhine in Germany. To overcome dispersal limitation we transferred freshly mown plant material from species-rich sources to a restoration site on a former arable field. Before plant material application, topsoil was removed to accelerate nutrient impoverishment and create favourable conditions for seedling recruitment.

Topsoil removal led to a drastic reduction in organic matter and essential mineral nutrients to the level of target communities (P) or even below (N, K). At a removal depth of 30 cm content of the soil seed bank that comprised exclusively of annual arable weeds, ruderals and some common grassland species, declined by 60 – 80%, while at a removal depth of 50 cm the seed bank was almost completely eliminated. With few exceptions, all species recorded in source plant material were found established at the restoration site. However, the overall correlation between seed content in plant material and establishment success was not very high.

Vegetation development at the restoration site was characterized by a rapid decline in arable weeds and ruderals, while resident grassland species and species transferred with plant material increased rapidly from the third year onwards. After four years as many as 102 species were established that could be exclusively attributed to plant material transfer, among them many rare and highly endangered plants. Establishment of species from plant material was most successful in regularly flooded plots, due to the suppression of competitors as well as the creation of favourable moisture conditions for seedling emergence.

Diaspore transfer with plant material proved to be an extremely successful method in restoring species-rich grassland. However, high quality of plant material and suitable site conditions with low competition in early stages of succession seem to be essential prerequisites.

Nomenclature: Wisskirchen & Haeupler (1998).

Stimulation of floating peat by the introduction of poorly humified peat from four cut-over bogs in The Netherlands was studied in a one-year outdoor experiment. The pH of the various peat substrates was increased by adding different amounts of lime: 0–2 to 4–8 g-CaCO₃.kg⁻¹ fresh peat. Both peat type and lime addition were found to affect the buoyancy of the peat substrates. Low nutrient concentrations in the peat, together with a high bulk density, proved to be unfavourable for creating floating peat. Three of the peat types proved to be too acidic (pH < 4.5) to produce sufficient methane (ca. 400–600 µmol.L⁻¹), and buoyancy was only achieved if lime was mixed in with the peat. The smallest amount of lime added (2 g.kg⁻¹ fresh peat) was sufficient to maintain buoyancy for at least one year. Lime addition did not stimulate nutrient mobilization by mineralization, although P, N and K concentrations in the peat water were relatively high. It is concluded that floating peat can be initiated by the introduction of poorly humified peat. If the peat substrates are too acidic, lime can be added to stimulate buoyancy of the peat. Results are discussed in relation to restoration prospects.

Nomenclature: van der Meijden (1996); Daniels & Eddy (1990).

Abbreviations: BV = Bargerveen reserve; DW = dry weight; HV = Haaksbergerveen reserve; MP = Mariapeel reserve; TP =Tuspeel reserve.

By the approval of the European Bird Directive (79/409/EEC) in 1979 and the Habitat Directive (92/43/EEC) in 1992, nature protection has become an important part of European law with direct consequences for land use, industrial development and agriculture. If a member state reclaims an area that is protected by these directives, it has to take compensational measures. When such an area includes saline grasslands that require very specific abiotic conditions, a place with similar conditions must be available to re-establish those grasslands at another location in a sustainable way. This will limit the number and extent of possible sites for compensation.

In the conflict between economy and ecology in the Schelde polders, Flanders has chosen to expand the port of Antwerp in the polders at the left Schelde bank and destroy a protected saline grassland site. As a consequence, it has to compensate for this loss. Therefore, we made a detailed study of the hydrology, geology and soil conditions of the endangered saline grassland site. The same was done in four possible compensation sites, all situated in nearby polders. We found that the presence of upwelling groundwater flowing through a saline peat layer is necessary for the occurrence of saline grasslands. Only in one of the four possible compensation sites, called Muggenhoek, we found such conditions. So, we indicate this place as a possible site for the re-creation of saline grasslands and give some recommendations for their development.

Nomenclature: van der Meijden (1996)

This paper describes the effects of re-establishing seasonal cattle grazing by 0.7 animal.ha⁻¹ on vegetation in a long-term abandoned, and partly degraded, semi-natural mountain pasture in the Šumava National Park, Czech Republic. There was very uneven grazing intensity inside the locality, and grazing preference changed during the season: cattle grazed most of the time in productive but species-poor Deschampsia cespitosa swards, but changed to a species-rich Violion caninae stand in the middle of the summer. A species-rich Carex rostrata community was only grazed at the end of the season. Species-poor swards dominated by Nardus stricta and Carex brizoides were mainly used as resting areas. Both grazing and excluding from grazing had a negative effect on species diversity of the Deschampsia cespitosa swards. The soil seed bank contained only few species that are characteristic of mountain grassland communities, and seed dispersal of the target species by cattle dung was also found to be very limited. Thus both grazing and exclusion from grazing are probably of limited value for the restoration of species-rich grasslands from species-poor Deschampsia cespitosa swards in this case.

Nomenclature: Oberdofer (1977) for syntaxa; Rothmaler (1995) for taxa, except for Dactylorhiza majalis Reichenb. ssp. turfosa Procházka and Poa subcaerulea Smith.

Secondary succession and seed bank formation was studied in a formerly grazed, abandoned, eastern Hungarian sandy steppe-meadow (Pulsatillo-Festucetum). The vegetation was sampled at different elevations of a sand dune which became partly invaded by the tree Robinia pseudo-acacia ca. 10 yr ago. Pre-abandonment vegetation records were used as historic references. Though composition of the non-invaded grassland only changed moderately, dominance of tall grasses (Elymus hispidus, Poa angustifolia) increased significantly at the cost of annuals and low stature perennials. In the stand invaded by Robinia most grassland species were lost and replaced by nitrophytes. Vertical position influenced species abundance, but affected the composition only moderately. Fine-scale zonation of the vegetation also changed with time. Species richness of the above-ground vegetation and the seed density of soil samples at the lower elevation were slightly greater than at the higher sites.

Seed banks of sensitive grassland specialists (e.g. Pulsatilla pratensis subsp. hungarica) disappeared during grass encroachment. Following extinction from above-ground vegetation, restoration must rely on dispersal from adjacent areas. In contrast, several annuals and perennials, which survived this degradation stage in the above-ground vegetation, possessed seed banks. Many of these species became extinct from the vegetation during the Robinia invasion but left viable persistent seeds. This fact is promising for restoration of the Potentillo-Festucetum sandy pasture. Competitive weedy species and sprouting Robinia can, however, limit seedling establishment.

Nomenclature: Simon (2000) for taxa; Borhidi (2003) for syntaxa.

Abbreviations: BIC = Bayesian Information Criterium, NMDS = Non-metric Multidimensional Scaling.

Small-scale landscape elements, such as ditch banks, play an important role in preserving plant species richness in agricultural landscapes. In this study, we investigate whether the seed bank might be useful for restoring the above-ground plant species richness. We studied the vegetation and seed bank composition at six species-rich and six species-poor ditch banks, where agri-environment schemes are running to maintain and enhance ditch bank plant diversity. We show that the number of species in the seed bank was low, regardless of the number of species in the established vegetation. Moreover, the seed bank was always dissimilar to the established vegetation. Target species for nature conservation were occasionally present in the seed bank at both species-poor and species-rich sites, but rarely so if the species was absent from the established vegetation. We conclude that the potential use of the seed bank for restoration of ditch banks is minimal. At present, plant species richness seems to be largely controlled by germination opportunities; high biomass and competition appear to hamper germination at species-poor sites. We recommend continued nutrient reduction at such sites. Soil disturbance measures and deliberate sowing should also be considered.

Nomenclature: van der Meijden (1996).

The diaspore bank (seeds of higher plants and spores of ferns and bryophytes) was assessed between 3 and 5 yr after experiments to control Pteridium aquilinum (bracken) and restore appropriate vegetation were initiated at two contrasting locations in the UK. We tested the response of the diaspore bank using univariate and multivariate analysis of variance. The two approaches were complementary and together improved the interpretation of these results. There were considerable differences in the diaspore banks of the two sites and among the experimental locations within sites. Within each experiment there were differences in species composition, with species that were (1) common to both diaspore bank and vegetation, (2) restricted to the diaspore bank and (3) restricted to the vegetation. There is a possibility of increasing the biodiversity of the developing vegetation if some of the species present in the diaspore bank can be germinated. This was especially true for ferns where four species were found in the spore bank which were not present in the vegetation. There were few significant effects of management treatment on the diaspore bank as the experiments had been in progress for only 3 to 5 yr, but a few species had different densities in the different treatments (Betula pubescens, Juncus effusus and some bryophytes). The greatest correlation between vegetation and diaspore bank was found at the top hierarchical level (entire dataset) and this progressively reduced with scale. We interpret this as a landscape/species pool effect: as the scale of the study reduces the correlation between diaspore bank and vegetation also reduces, at least over the time scale of our study. The relevance of these results for restoration ecology is discussed briefly.

Nomenclature: Stace (1997) for higher plants and ferns; Smith (1978) for bryophytes.

Abbreviations: RDA = Redundancy analysis.

In terms of restoration planning, the analysis of natural regeneration processes represents a valuable starting point for the selection of suitable species to be used. This paper aims to identify colonizing key species among the pioneer vegetation of limestone quarries in Lebanon, to identify potential restoration strategies in terms of reconstitution of the pre-mining vegetation cover. Characteristics of the major ground colonizers after disturbance were identified in a representative quarry in the thermo-Mediterranean biozone. The floristic inventories resulted in a matrix of cover values of 107 species × 14 plots. Correspondence analyses were used to pinpoint similarities in the distribution of key species among the different environmental characteristics of sites. The main results reveal a heterogeneous floristic composition along the regeneration gradient, where annual R-strategy taxa such as Inula viscosa and Ainsworthia cordata dominate on very perturbed and degraded sites. Less degraded areas within the quarry were rich in herbaceous perennial or shrub species such as Geranium dissectum, Stachys distans, Salvia triloba and Ptilostemon chamaepeuce. On relatively non-degraded areas woody and shrub perennials such as Pinus brutia, Pistacia palaestina and Quercus calliprinos dominate, along with less stress tolerant taxa such as Arbutus andrachne and Cistus creticus. Species to be used in restoration projects should be chosen from among the local vegetation, according to frequency of occurrence during the whole succession process which will reflect their adaptability to local conditions and their relevance to restoration objectives.

Nomenclature: Mouterde (1966).

Closed canopy vegetation often prevents the colonization of plant species. Therefore the majority of plant species are expected to appear at the initial phase of post-agricultural succession in mesic forest environment with moderate levels of resources. This hypothesis was tested with data from the Buell-Small Successional Study, NJ, USA, one of the longest continuous fine-scale studies of old-field succession. The study started in 1958, including old fields with different agricultural histories, landscape contexts, and times of abandonment. In each year of the study, the cover values of plant species were recorded in 48 permanent plots of 1 m2 in each field. We analysed the temporal patterns of colonization at plot scale and related these to precipitation data and other community characteristics. The number of colonizing species decreased significantly after ca. 5 yr, coinciding with the development of a continuous canopy of perennial species. However, species turnover remained high throughout the whole successional sequence. The most remarkable phenomenon is the high inter-annual variation of all studied characteristics. We found considerable temporal collapses of vegetation cover that were synchronized among fields despite their different developmental stages and distinctive species compositions. Declines of total cover were correlated with drought events. These events were associated with peaks of local species extinctions and were followed by increased colonization rates. The transitions of major successional stages were often connected to these events. We suggest that plant colonization windows opened by extreme weather events during succession offer optimum periods for intervention in restoration practice.

Nomenclature: Gleason & Cronquist (1991).

Abbreviation: BSS = Buell-Small Succession Study.

We tested simulated effects of herb competition on the performance of planted seedlings of Quercus faginea ssp. faginea in Mediterranean abandoned cropland. We produced three types of environment with respect to herb competition: absence of competition (AC), below-ground competition (BGC), and total competition (TC). We assessed the performance of Q. faginea seedlings in each treatment in five ways: (1) seedling mortality, (2) leaf length and total plant leaf area, (3) water potential, (4) total biomass and biomass allocation, and (5) non-structural carbohydrate storage in different plant organs. We also measured (6) soil moisture at different depths and (7) biomass production of herbs. The TC treatment reduced water availability more than the BGC treatment, in agreement with the most pronounced water stress in seedlings under TC conditions. BGC and TC treatments showed a high and similar seedling mortality, which was one order of magnitude higher than that in the AC treatment. Competition treatments affected glucose concentration in both shoots and roots, and followed the rank TC > BGC > AC. Q. faginea seedlings might compensate a lower water availability through glucose accumulation in leaves to reduce the osmotic potential. There was a maximum starch concentration in the BGC treatment that hints that a moderate resource limitation would limit tissue growth but not carbon assimilation. We conclude that the negative effects of herbs on Q. faginea seedlings are mostly a result of competition for water, and that this competition is noticeable since the earliest stages of the establishment. Complete weed removal is a technique that would strongly improve seedling survivorship.

Abbreviations: AC = Absence of competition; BGC = Below-ground herb competition; TC = Total herb competition.

Throughout the Mediterranean region, vegetation dynamics are affected by human activities which are either ‘stresses’ or ‘disturbances’, depending on their frequency, intensity and spatial distribution. To minimize or reduce anthropogenic degradation caused by land use and other disturbances, it is necessary to understand and predict the various responses of plant communities to disturbances. In particular, detailed but integrative approaches are required to assimilate large databases on vegetation and to make them directly useful for managers and restorers.

We describe two case studies undertaken to evaluate the effects of logging or overgrazing on plant species diversity in pine forests of southern France and steppe ecosystems of southern Tunisia. Both studies employed the same methodology to identify plant functional traits (morphological, life history and regeneration traits) associated with community response to disturbance. The results of these analyses allowed us to develop state and transition models that could be used to plan and predict ecosystem trajectories, assess ongoing degradation processes and monitor community and ecosystem responses to management and restoration practices. We discuss the relevance and the use of plant functional types (PFTs) as tools for ecosystem management and planning and for monitoring restoration in southern Europe, northern Africa and elsewhere. Using this approach it is possible to improve management strategies for the conservation, restoration and sustainable exploitation of biodiversity and of ecosystems.

Nomenclature: Le Floc'h & Boulos (In press); Tutin et al. (1964–1980).

Abbreviations: GLM = Generalized linear model; LDMC = Leaf dry matter content; PPC = Perennial plant cover; SLA = Specific leaf area.

Grassland communities are increasingly recognized as disturbance-dependent ecosystems, yet there are few replicated, multi-site studies documenting vegetation responses to varying frequencies and types of grassland disturbance. Even so, land managers frequently manipulate disturbance regimes in an attempt to favour native grassland plants over exotic species. We conducted a factorial experiment testing three frequencies of clipping combined with litter accumulation, litter removal, and soil disturbance within the highly threatened California coastal prairie plant community. We monitored the response of native/exotic, grass/forb plant guilds once a year for four years. More frequent clipping reduced cover of exotic grasses and favoured exotic forbs, whereas native species were largely unaffected by clipping frequency. Litter accumulation, litter removal, and soil disturbance did not affect vegetation composition. Effects of litter accumulation may take longer than our experiment allowed, and soil disturbance due to our treatments was not sufficiently strong to show consistent effects relative to mammalian soil disturbance. Treatment response of some plant guilds differed among sites, highlighting the importance of replicating experiments at several sites before recommending conservation management practices.

Abbreviation: UCSC = University of California, Santa Cruz.

Nomenclature: Hickman (1993).

The impact of cattle grazing on the vegetation of calcareous fens was compared to the effects of traditional autumn mowing in southern Germany. Vegetation composition was studied in adjacent pairs of fen meadows and pastures with similar environmental conditions and biomass production. Vegetation data were analysed with respect to species richness, species composition and response of species traits to disturbance, including morphology, defence mechanisms, clonal growth form and generative reproduction. Species richness was significantly reduced by grazing, but the percentage of typical fen species or Red Data Book species was not affected by land use type. Detrended Corrspondence Analysis indicated that species composition could best be explained in terms of a land use gradient. Species traits showed a clear trend in their response to land use type. Grazing favoured grasses and small forbs. Only a few species with defence mechanisms against foraging were more frequent or abundant on pastures. Many other species with defence mechanisms, however, did not have an advantage on pastures. Flowering and seed dispersal traits did not respond significantly to grazing or mowing. Species with fast spreading stem derived clonal organs were favoured on pastures, whereas all other clonal growth forms and, particularly, non-clonal species were more abundant on meadows. More indicator species of wet soil conditions and species adapted to flooding were found on pastures. Grazing can be recommended as an alternative land use to mowing in contrast to abandonment, but a reduction in species richness and changes in species composition and species traits may occur.

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

The impact of grazing pressure on gas exchange of Periploca laevigata was studied in relation to its nutritional status. P. laevigata, a woody and highly palatable shrub, is an important forage species in the dry season in Cabo de Gata Natural Park (Almeria, SE Spain) where this study was carried out. Seasonal and diurnal courses of net photosynthesis, transpiration and stomatal conductance were measured in the field. In addition, soil and plant nutrient status were measured as potential factors influencing leaf photosynthetic levels. Early in the growing season, ungrazed P. laevigata had higher photosynthetic activity than grazed plants suggesting that the defoliated plants were still recovering from herbivore damage in the previous summer. Later in the growing season grazed P. laevigata had higher photosynthetic activity than ungrazed plants, suggesting higher metabolic activity and a possible investment in chemical defences. Concentrations of P and N in the soil were higher in the grazed area. The nutrient concentration of the leaves of P. laevigata was similar in grazed and ungrazed plants.

Abbreviations: HG = High grazing disturbance; LG = Ceased grazing.

The role of sheep grazing on vegetation change in upland mires removed from livestock farming and surrounded by conifer plantation was investigated with a grazing trial at Butterburn Flow in northern England. Paired grazed and ungrazed plots from central and peripheral locations were compared over 14 yr. Vegetation data from 34 mires in Kielder Forest provided an ordination framework within which vegetation trends were investigated. A gradient from dry moorland/hummock to wet mire/hollow vegetation dominated this framework and may reflect hydrological variability and structural vegetation differences between the mires.

Some species were significantly affected by change in grazing intensity and there were differences between the edge and the centre of the mire. Overall vegetation change depended upon the grazing management and the position of the plots such that the removal of sheep grazing decreased the cover of species typical of wet ombrotrophic conditions, but only at the periphery of the mire. The vegetation in one plot became very similar to that of mires elsewhere in Kielder Forest where sheep were removed several decades ago.

Cessation of grazing on upland mires is likely to lead to slow structural and species change in vegetation at the mire edge with a long-term loss of ombrotrophic species. The nature conservation significance of these changes will depend upon whether or not management objectives target natural conditions or wish to maximize ombrotrophic vegetation. The context of external factors such as climate and pollution may, however, be more important in determining site condition on the wettest mires.

In France, most civil engineering and excavation projects are at present accompanied by compensatory measures with the aim of preserving biodiversity. In order to avoid the destruction of a habitat of high conservation interest in NE France, harbouring two legally protected plant species, an experiment of soil translocation was conducted on an area of 1 ha. The donor site was an extensively managed mesophilic meadow and the receiving site was a neighbouring arable land. The vegetation of the translocated meadow was described 8 and 17 months after soil translocation, and compared (1) with vegetation resulting from more classical restoration techniques tested on the arable land (natural regeneration and seed mixture sowing) and (2) with the soil seed bank and vegetation previously present on the donor site. Results showed that the soil translocation technique permitted the development of many meadow species, including two legally protected species, and few ruderal species despite a large area of bare ground. This technique seems effective in terms of number and abundance of meadow species compared to natural regeneration and commercial seed sowing. In the case of the two classical methods, species richness was lower and only widespread species were present. Topsoil translocation provides a good compensatory method to avoid habitat and species destruction. However, the study should be continued, with the aim of assessing the longer term development and stabilization of the vegetation of the translocated meadow.

Nomenclature: Lambinon et al. (1992).