Effects of selective clipping and mowing time on species diversity in chalk grassland

Phytomass distribution and species diversity were followed in a chalk grassland with different selective clipping treatments during 4 years. Removal of the dominantBrachypodium resulted in a sharp increase in forb phytomass and in species number. The dominance-diversity curve changed in shape from geometric to log-normal. Obviously,Brachypodium restricted the growth of most other species. Removal of all species except the dominant showed, in contrast to the niche pre-emption theory, a marked increase in phytomass and reproductive effort ofBrachypodium. It seems that other mechanisms can also lead to a geometric distribution. Removal in a type of vegetation without obvious dominants and with a log-normal species distribution revealed that interspecific competition is not an important factor in this vegetation. This suggested a low intensity of species interaction and a large influence of restricting density-independent factors. Finally, to reduce the dominance ofBrachypodium we implemented a 4-year mowing experiment. Mowing earlier in the season resulted in a reduced exclusion of species byBrachypodium. This alternative mowing time may be sufficient to restore species diversity in chalk grassland. Experiments are under way to further substantiate this conclusion.     

Short-term effects of nitrogen enrichment,litter removal and cutting on a Mediterranean grassland

Semi-natural grassland communities are of great interest in conservation because of their high species richness. These communities are being threatened by both land abandonment and nitrogen eutrophication, and their continued existence will depend upon correct management. However, there is a distinct lack of studies of the ecological mechanisms that regulate species diversity and productivity in Mediterranean grasslands. We have conducted a 3-year field experiment in a species-poor grassland in central Italy to investigate the effects of nitrogen fertilization coupled with removal of plant litter and artificial cutting on species diversity and community productivity. Vegetation cutting reduced living biomass but increased species diversity. In fact, cutting had positive effects on the cover of almost all of the annual and biennial species, while it had a negative effect on the dominant perennial grasses Brachypodium rupestre and Dactylis glomerata. Litter removal had similar effects to cutting, although it was far less effective in increasing species diversity. In contrast, nitrogen enrichment strongly increased the living biomass while maintaining very low species diversity. Our results have indicated that semi-natural Mediterranean grasslands need specific management regimes for maintenance and restoration of species diversity. In the management of these grasslands, attention should be paid to the potential threat from nitrogen enrichment, especially when coupled with land abandonment.     

Short-term effects of nitrogen enrichment, litter removal and cutting on a Mediterranean grassland

Semi-natural grassland communities are of great interest in conservation because of their high species richness. These communities are being threatened by both land abandonment and nitrogen eutrophication, and their continued existence will depend upon correct management. However, there is a distinct lack of studies of the ecological mechanisms that regulate species diversity and productivity in Mediterranean grasslands. We have conducted a 3-year field experiment in a species-poor grassland in central Italy to investigate the effects of nitrogen fertilization coupled with removal of plant litter and artificial cutting on species diversity and community productivity. Vegetation cutting reduced living biomass but increased species diversity. In fact, cutting had positive effects on the cover of almost all of the annual and biennial species, while it had a negative effect on the dominant perennial grasses Brachypodium rupestre and Dactylis glomerata. Litter removal had similar effects to cutting, although it was far less effective in increasing species diversity. In contrast, nitrogen enrichment strongly increased the living biomass while maintaining very low species diversity. Our results have indicated that semi-natural Mediterranean grasslands need specific management regimes for maintenance and restoration of species diversity. In the management of these grasslands, attention should be paid to the potential threat from nitrogen enrichment, especially when coupled with land abandonment.     

Long-term after effects of fertilization on above-ground phytomass and species diversity in calcareous grassland

Abstract. Long-term after effects on species number and productivity in calcareous grassland were analyzed after cessation of fertilization. Three series of permanent plots were monitored yearly from 1971 to 1993. These series differed in duration of fertilization and in fertilizer composition, notably the amount of nitrogen and phosphorus. Yearly above-ground production decreased in all series after fertilization had been stopped, however at different speeds. The grass/forb ratio also decreased, while species number and Shannon index of diversity (H') increased. In the series where fertilizer treatment was stopped in 1967 (1968-series), productivity and grass/forb ratio decreased equally as in the plots where fertilization with a high nitrogen content was stopped in 1979 (80/Npk-series). However, species number in the plots of the 80/Npk-series increased faster than in the 1968-series. This was probably the result of a higher number of species present in the seed rain from the surrounding vegetation in the period after 1980 than from after 1968. In the plots receiving a high amount of phosphorus (80/nPk series), the productivity decreased more slowly than in the high nitrogen plots (80/Npk-series). At approximately the same total production level, the grass/forb ratio remained higher for another five-year period in the 80/nPk-series. Species number and the Shannon index of diversity increased more slowly in the 80/nPk-series than in the 80/Npk-series. Over a given range of productivity, changes in species number and Shannon index correlated better with the grass/forb ratio than with total above-ground phytomass. Therefore, restoration of species-rich grassland should not only be focused on lowering the yearly production, but also on reducing the grass component of the vegetation.     

Habitat structure mediates top–down effects of spiders and ants on herbivores

Differences in structural complexity of habitats have been suggested to modify the extent of top–down forces in terrestrial food webs. In order to test this hypothesis, we manipulated densities of generalist invertebrate predators and the complexity of habitat structure in a two-factorial design. We conducted two field experiments in order to study predation effects of ants and spiders and, in particular, of the wasp spider Argiope bruennichi on herbivorous arthropods such as grasshoppers, plant- and leafhoppers in a grassland. Predator densities were manipulated by removal in habitats of higher and lower structural diversity, and the effects on herbivore densities were assessed by suction sampling. Habitat structure was changed by cutting the vegetation to half its height and removing leaf litter.We found a significant negative effect of this assemblage of generalist predators on plant- and leafhoppers, which were 1.6 times more abundant in predator removal plots. This effect was stronger in low-structured (cut) than in uncut vegetation. Densities of the most abundant planthopper Ribautodelphax pungens (Delphacidae) were 2.2 times higher in predator removal plots. Furthermore, adult plant- and leafhoppers responded more strongly than juveniles and epigeic species more strongly than hypergeic species. The presence of predators had a positive effect on plant- and leafhopper species diversity. In a second field experiment, we tested the exclusive impact of Argiope bruennichi on its prey, and found that its effect was also significant, although weaker than the effect of the predator assemblage. This effect was stronger in grass-dominated vegetation compared to structurally more complex mixed vegetation of grasses and herbs. We conclude that habitat structure and in particular vegetation height and architectural complexity strongly modify the strength of top–down forces and indirectly affect the diversity of herbivorous arthropods.     

Species diversity and primary productivity inMiscanthus sinensis grasslands

In an old field grassland dominated byMiscanthus sinensis Anderss. the community structures, phytomass, dominance ofM. sinensis and species diversity were measured. Species and life form composition of the stand were characterized by higher percentages of therophytes, woody and shrubby species, liana and alien species. From May so September in 1982, all the aboveground parts were harvested from each of the four quadrats (2 m×2 m) once a month. Seasonal peak of aboveground phytomass, in September, was 1027 g d.w.m⁻² to whichM. sinensis contributed as much as 96.5%. With the progress of the growing season,M. sinensis became increasingly important both in stand phytomass and in dominance, whereas species diversity based on the dry weight contributions of constituent species decreased. Our analysis of these seasonal trends showed that the diversity was largely a function of dominance of the most important species, rather than that of stand phytomass or productivity. The simultaneous measurements of 20 quadrats in late August 1983, also supported the above conclusion.     

Vertical canopy structure of Dutch chalk grasslands in relation to their management

Analysis of leaf canopy overtopping relationships was carried out using a non-destructive point quadrat method followed by a destructive stratified harvest of the above-ground phytomass in Dutch chalk grasslands with different management: summer sheep grazing and annual autumn mowing. The two methods of analysis are compared: e.g. relative leaf overtopping can be recorded by the point quadrat method but it is obscured in vertical vegetation profiles based on stratified phytomass distribution. However the stratified harvest method describes the relationship between canopy phytomass and light microclimate, recorded by measuring Photosynthetically Active Radiation (PAR) at different heights in the vegetation. Plant growth form during peak standing crop is of greater significance than Raunkiaerian life form in determining structure of chalk grassland vegetation. In annually mown grasslands, the tall graminoid growth form, shown by Brachypodium pinnatum, reduces PAR in the lower canopy and suppresses most other growth forms except those which can reach the higher canopy levels, e.g. clumped herbs such as Origanum vulgare. In contrast, grazing can result in a reduction of dominance from the tall graminoids and reduction of the abundance of taller, grazing-sensitive herbs, e.g. clumped and climbing herbs such as Origanum and Lathyrus pratensis, and an increase in grazing-tolerant species, e.g. smaller rosette herb growth forms, e.g. Leontodon hispidus and shorter rhizomatous or stoloniferous graminoids, e.g. Carex flacca and Briza media. Changes in both the overtopping hierarchy at the peak of the growing season and the intensity of overtopping in the course of a growing season are of conclusive importance in determining the relative abundance of species in the vegetation.     

Fire does not alter vegetation in infertile prairie

The paradigm in prairie ecology is that fire is one of the key factors determining vegetation composition. Fire can impact grassland ecosystems in various ways, including changing plant species composition and inducing nitrogen loss. I found that 17 years of different burning frequencies in infertile grassland had only a minor impact on the vegetation composition and diversity. The only major impact from increasing the frequency of fires was a decrease of Poa pratensis abundance. However, other plant species did not respond to the change in Poa abundance. This result contrasts with previous studies in savannas and more productive grasslands, where the balance between trees, grasses, and the elimination of the litter layer can result in large vegetation changes. However, in this system primary productivity was low, litter did not accumulate and no major vegetation shifts occurred. Thus, the long-term vegetation impacts of burning in an infertile, low-productivity prairie were minimal.     

Multi-scale impacts of crested wheatgrass invasion in mixed-grass prairie

Most of North America’s northern Great Plains have been cultivated for crop production, leaving remnants of natural mixed-grass prairie fragmented and threatened by alien plant invasions. The region’s most widespread alien perennial forage crop, crested wheatgrass (Agropyron cristatum sensu amplo), has invaded native grassland and raised concerns regarding its ecological impact. To evaluate impacts at multiple scales of organization, adjacent invaded and uninvaded mixed-grass prairie were sampled at eight widely separated locations. At the population level, native C₃ mid-grasses and forbs were less abundant in invaded grasslands, while native C₃ and C₄ short-grass abundance was not different. At community and landscape levels, diversity was lower in invaded grasslands largely because of lower forb species richness and cover, and crested wheatgrass dominance of both cover (14% basal cover) and seedbank (404 seeds m⁻²). At the ecosystem level, both vegetation and litter biomass were greater in invaded grasslands, however, below ground organic matter (roots and litter), soil organic carbon, total nitrogen and phosphorus were not different. Crested wheatgrass invasion of mixed-grass prairie was associated with lower diversity within and among plant communities, and appears to simplify the composition of mixed-grass prairie landscapes. Hypotheses for crested wheatgrass dominance and persistence following invasion are suggested.     

Plant responsiveness to variation in precipitation and nitrogen is consistent across the compositional diversity of a California annual grassland

Question: How does responsiveness to water and Nitrogen (N) availability vary across the compositional and functional diversity that exists in a mesic California annual grassland plant community? Location: Northern California annual grassland. Methods: A mesocosm system was used to simulate average annual precipitation totals and dry and wet year extremes observed in northern California mesic grasslands. The effects of precipitation and N availability on biomass and fecundity were measured on three different vegetation types, a mixed grass forb community, and a forb and a grass monoculture. The treatment effects on plant community composition were examined in the mixed species community. Results: While growth and seed production of the three vegetation types was inherently different, their responses to variation in precipitation and N were statistically similar. Plant density, shoot biomass, and seed production tended to increase with greater water availability in all vegetation types, with the exception of a consistent growth reduction in high precipitation (1245 mm) plots in the first year of the study. Shoot biomass responded positively to N addition, an effect that increased with greater water availability. Nitrogen addition had little effect on plant density or seed production. In the mixed grass‐forb community, biomass responsiveness to water and N treatments were consistently driven by the shoot growth of Avena barbata, the dominant grass species. Conclusions: Vegetation responses to changes in precipitation and N availability were consistent across a range of composition and structural diversity in this study. Plant growth and seed production were sensitive to both increased and decreased precipitation totals, and the magnitude of these responses to N availability varied depending on soil moisture conditions. Our results suggest the impacts of changing precipitation regimes and N deposition on annual productivity of California grasslands may be predictable under different climate scenarios across a range of plant communities.     

Fine-scale spatial distribution of leaves and shoots of two chalk grassland perennials

The fine-scale spatial distribution of leaves and shoots of Brachypodium pinnatum and Carex flacca, two rhizomatous graminoids, was investigated in two chalk grasslands in South Limburg (The Netherlands). The objective was to examine whether leaves and shoots of Brachypodium, a dominant species, had a regular distribution on a small scale, as has been suggested for other clonal species that form high-density stands. Patterns were compared to Carex, which is never found to be as abundant as Brachypodium.The number of shoots and leaf contacts were counted in small quadrats, grouped in a grid. Using Moran's I analysis for autocorrelation, it appeared that leaves and shoots of both species were arranged in clumps, and that these clumps were randomly distributed across the soil surface. Shoot clumps in Carex were smaller in diameter and not as pronounced as those in Brachypodium.In most cases, patterns of leaves and shoots were positively correlated, indicating that leaves were predominantly positioned above and around the groups of quadrats where the shoots were attached. However, in dense stands of Brachypodium the positions of leaf clumps were not correlated to those of shoot clumps. This is a result of the tall growth form of this species and its high shoot densities, and it is suggested that this will be a characteristic of any species that dominates a dense stand.     

Germinable soil seed-bank of former grassland converted to coniferous plantation

The influence of afforestation with cedars on field layer vegetation and on the germinable soil seed-bank were investigated along a 60-m transect merging from open grassland to sparse and dense canopy cover. A total of 132 species were found, 76 in the seed-bank and 109 in the vegetation, with 53 species in common. Conifer cover was not found to be associated with a decrease in total number of species in the vegetation or seed-bank, but the mean number of species in the vegetation, total cover in field layer vegetation and mean number of individuals in the seed-bank decreased significantly from grassland to forest stands. The grassland seed-bank was dominated by Saxifraga tridactylites and Veronica agrestis; the seed-bank of plots of scattered cedars was dominated by Trifolium incarnatum ssp. molinerii; and that of dense cedar plantations was dominated by Campanula rapunculus. The number and cover of grassland species of field layer vegetation decreased in the forest, with respect to open grassland, and the same trend was found for density of individuals in the seed-bank. It is concluded that grassland restoration by cutting cedars cannot rely on the presence of grassland species in the soil seed-bank.     

Vegetation and seed bank in a calcareous grassland restored from a Pinus forest

Question: What is the importance of the seed bank in the maintenance of the restoration potential of a 60‐year‐old abandoned calcareous grassland overgrown by Pinus trees? Location: ‘Les Pairées’, province of Luxembourg, Belgium. Methods: The seed bank and the above‐ground vegetation were surveyed in three adjacent stands, previously forming a unique calcareous grassland: a 60‐year‐old Pinus forest, a four‐year‐old clear‐cutting and a typical calcareous grassland. Floristic diversity was compared among stands and between vegetation and seed bank. Results: The species richness of the vegetation and the seed bank was significantly lower in the Pinus forest. More floristic similarities were found between the clear‐cutting and the calcareous grassland. Seed bank was essentially transient, dominated by annual species. Its correspondence with the above‐ground vegetation was weak. Conclusion: Very few calcareous grassland species have persisted in the Pinus stand. Four years after clear‐cutting, the stand was nearing restoration towards a calcareous grassland. Seed longevity in the soil was not the most explicative factor. Dispersal of propagules from adjacent sources was also important.     

Bird community composition across an Andean tree‐line ecotone

Few studies have found strong evidence to suggest that ecotones promote species richness and diversity. In this study we examine the responses of a high‐Andean bird community to changes in vegetation and topographical characteristics across an Andean tree‐line ecotone and adjacent cloud forest and puna grassland vegetation in southern Peru. Over a 6‐month period, birds and vegetation were surveyed using a 100 m fixed‐width Distance Sampling point count method. Vegetation analyses revealed that the tree‐line ecotone represented a distinctive high‐Andean vegetation community that was easily differentiated from the adjacent cloud forest and puna grassland based on changes in tree‐size characteristics and vegetation cover. Bird community composition was strongly seasonal and influenced by a pool of bird species from a wider elevational gradient. There were also clear differences in bird community measures between tree‐line vegetation, cloud forest and puna grassland with species turnover (β‐diversity) most pronounced at the tree‐line. Canonical Correspondence Analysis revealed that the majority of the 81 bird species were associated with tree‐line vegetation. Categorizing patterns of relative abundance of the 42 most common species revealed that the tree‐line ecotone was composed primarily of cloud forest specialists and habitat generalists, with very few species from the puna grassland. Only two species, Thlypopsis ruficeps and Anairetes parulus, both widespread Andean species more typical of montane woodland vegetation edges, were categorized as ecotone specialists. However, our findings were influenced by significant differences in species detectability between all three vegetation communities. Our study highlights the importance of examining ecotones at an appropriate spatial and temporal scale. Selecting a suitable distance between sampling points based on the detection probabilities of the target bird species is essential to obtain an unbiased picture of how ecotones influence avian richness and diversity.     

Distribution and effects of tree leaf litter on vegetation composition and biomass in a forest-grassland ecotone

Aims After abandonment of grasslands, secondary succession leads to the invasion by woody species. This process begins with the accumulation of tree litter in the forest–grassland ecotone. Our objectives were to determine the relationships between litter amounts and vegetation composition and cover along natural forest–grassland ecotones and to experimentally study the initial effects of tree litter accumulation on grassland vegetation and on microsite conditions.Methods We established 11 transects varying from 12 to 15 m in length in different forest–grassland ecotones in the Lahn-Dill highlands, Germany, and measured the mass and cover of tree litter and the cover and composition of vegetation at five sequential positions along each transect by using 1 m 2 plots with five replications. In a field experiment, we established plots subjected to different litter amounts (0, 200 and 600g m ?2) and evaluated changes in grassland vegetation, soil temperature and soil nutrient availability below the litter layer.Important findings Tree litter amounts decrease from 650 to 65g m ?2 across the forest–grassland ecotone. Vegetation changed from shrubs and annual species (adapted to more stressful conditions) in the forests edge to grasses, rosettes and hemirosette species (with higher competitive abilities) in the grassland. These anthropogenic forest–grassland ecotones showed abrupt edges, and the two adjacent ecosystems were characterized by different species pools and functional groups. In the field experiment, the presence of a litter layer reduced vegetation biomass and cover; the species richness was only reduced in the treatment with high litter (600g m ?2). Additionally, adding litter on top of vegetation also reduced thermal amplitude and the number of frost days, while increasing the availability of some nutrients, such as nitrogen and aluminium, the latter being an indicator of soil acidification. Adding a tree litter layer of 600g m ?2 in grassland areas had strong effects on the composition and diversity of grassland vegetation by reducing the cover of several key grassland species. In, or near, forest edges, litter accumulation rapidly changes established vegetation, microsite conditions and soil nutrients.     

Effects of herbaceous plant functional groups on the dynamics and structure of an alpine lichen heath: the results of a removal experiment

Alpine lichen heaths are polydominant, low-productive communities where lichens and, at some localities, the dwarf shrub Vaccinium vitis-idaea prevail. To analyse the role of herbaceous dominants in the structure of alpine heaths, we established a removal experiment. We tested (1) whether dominant graminoids and forbs differ in their effects on species richness, phytomass, and abundance of individual species; and (2) which remaining species are able to replace the removed dominants. Permanent plots were established in 1996 in the Teberda Reserve (the Northwestern Caucasus, Russia) at 2750 m a.s.l. with four treatments: (1) control, (2) forb removal, (3) graminoid removal, (4) graminoid and forb removal. Target species were clipped every year to avoid regrowth. We counted the shoot numbers of all vascular plants yearly from 1996 to 2009. In 2010, we harvested the aboveground phytomass. We used mixed-effects models to assess the responses of the remaining species and phytomass fractions to the removal. The biomass of the removed dominants was almost compensated for by the remaining species, but due to diffuse competition none of the subordinate species became a new dominant. Graminoid removal reduced community weighted mean leaf dry matter content and litter accumulation. Species number per plot completely recovered after graminoid, not forb removal. Shoot numbers of Antennaria dioica, Arenaria lychnidea, Campanula tridentata, Ranunculus oreophilus, and Trifolium polyphyllum showed positive responses to graminoid removal. Anemone speciosa shoot numbers decreased after graminoid removal. In alpine heath, graminoid dominants contribute more to community structure than forb dominants.     

Effects of the litter layer of Pteridium aquilinum on seed banks under experimental restoration

Questions: Does the litter layer of Pteridium aquilinum (bracken) act as a barrier to certain species in the seed bank? Does bracken control/restoration treatment affect seed transfer through the litter layer? Location: Five experiments at three sites across the UK covering two major vegetation types; acid‐grassland and heath‐land. Methods: At each experiment a range of bracken control and vegetation restoration treatments were applied for about ten years. The seed bank was sampled in both the bracken litter and the soil. The cover (%) of each species in the vegetation and the bracken litter abundance (cover and depth) was also estimated. Results: The bracken litter layer acts as an inert barrier as it contained a large proportion of seeds available in the litter‐soil profile (38%– 67% of the total). Bracken litter depth and cover also influenced significantly the seed bank composition in both the bracken litter and the soil. These effects were site‐specific, and species‐specific. The application of treatments changed significantly the balance between seed inputs and outputs in the bracken litter layer for some species. This was either a positive or negative response relative to the untreated control plots. Conclusion: For heathland and acid‐grassland restoration, the bracken litter layer may be an important seed source, but it must be disturbed particularly before seed addition.     

Site‐specific responses of native and exotic species to disturbances in a mesic grassland community

Abstract. 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.     

Realistic Variation in Species Composition Affects Grassland Production,Resource Use and Invasion Resistance

We investigated the effects of realistic variation in plant species and functional group composition, with species occurring at realistic abundances, on ecosystem processes in exotic-dominated California grassland communities. Progressive species removals from microcosm communities, designed to mimic nested variation in diversity observed in the field, reduced grassland production, resistance to intentional invasions, and resistance to natural colonization by new species. Three lines of evidence point to the particular importance of intensified competition within a single functional group—late-active forbs—in explaining the observed effects of realistic species loss order on community resistance. First, reduced success of naturally colonizing species in more diverse assemblages was dominated by declining colonization by late-active forbs. Second, increasing late-active forb biomass appeared to reduce the biomass of intentionally introduced yellow starthistle (Centaurea solstitialis, a late-season forb) both within and across diversity levels. Finally, starthistle addition reduced biomass of resident late-season forbs but not of any other functional group. Increasing diversity increased light levels and soil moisture availability in spring and summer, providing a proximate mechanism linking our realistic species loss order to decreased community resistance. Starthistle addition reduced light and soil moisture availability but not N across richness levels, mirroring the apparent effects of the additional late-active forb species present in higher diversity treatments. Species losses that entail the early loss of whole or key functional groups could, through mechanisms like those we explore, have greater ecosystem consequences than those suggested by randomized-loss experiments.     

Fifty years vegetation development of a xerothermic calcareous grassland in Central Europe after heavy disturbance

Fifty years ago on the south-facing slope of a limestone hill 4 km NE of Göttingen (Germany) a small plot of 4 m² size was chosen in a xerothermic calcareous grassland (Mesobromion alliance) for investigation. The formerly grazed slope was abandoned a few years prior to the study, but in 1987 intermittent grazing started again. The mean annual temperature in Göttingen (1953–2003) was 8.8 °C on the average; the annual mean increased by 1.1 °C during the study period. Mean annual precipitation amounted to 642 mm (393–1093 mm). The mean monthly precipitation during summer (April–August) varied in the range between 29 and 101 mm. In the years 1953–2003 the presence of species was recorded annually in 400 subplots (100 cm² each). In part of this time also the amount of bare soil within the plot was recorded, and standing crop and the nitrogen contents in leaves of Bromus erectus were measured in the immediate surrounding of the plot.In fall 1953 the vegetation was removed completely in half of the plot, in the other half the two dominant grasses Bromus erectus and Brachypodium pinnatum were left. The differences between the two halves vanished already after 2 years (starting phase 1953–1955). Thus, only results concerning the plot as a whole are reported here. During the investigation three periods could be distinguished. After the starting phase in period I (1955–1986) total presence, presence of the most important species, species richness, number of endangered species, diversity and evenness increased. In this way the grassland regenerated after the heavy disturbance, and a dense, species-rich vegetation formed. Only a few species showed maximum values already within the first 10 years and faded out later.Period II (1987–1997) spanned 10 years of grazing. During this time total presence, presence of many important species, species richness, number of endangered species, diversity and evenness decreased, whereas areas with bare soil increased. Only two species showed maximum values during this phase, and just one new species invaded (Lolium perenne). During this period a more open type of grassland was formed. Period III (1998–2003) spanned 5 years without grazing and only one grazing year (2002). Here, a partial regeneration of a more closed grassland took place with traits similar to period I.Several phenomena occurred continuously through all three periods. Bromus erectus always was the dominating species. Nevertheless, proportions of graminoids (in % total presence) were lowered, and the proportion of herbs increased. The ratio Bromus erectus/Brachypodium pinnatum was determined mainly by Brachypodium. Seedlings of woody plants were always present, but in most cases survived only one summer. Shrubs did not settle inside the plot, although small bushes developed in the immediate surrounding. In summary the 50-year process can be described as a slow recovery of a calcareous grassland after very heavy disturbance, modified by intermittent grazing, without formation of shrub vegetation.