Rotational fallows as overwintering habitat for grassland arthropods: the case of spiders in fen meadows

Regular mowing of grassland is often necessary for plant conservation, but uncut vegetation is needed by many arthropods for overwintering. This may lead to conflicting management strategies for plant and arthropod conservation. Rotational fallows are a possible solution. They provide a spatio-temporal mosaic of mown and unmown areas that may combine benefits to both plants and arthropods. We tested if rotational fallows enhance spider overwintering in fen meadows. Rotational fallows consisted of three adjoining strips 10 m wide and 35–50 m long. Each year, one of these strips was left unmown (fallow) in an alternating manner so that each strip was mown two out of three years. Spiders were sampled during spring with emergence traps in nine pairs of currently unmown fallow strips and completely mown reference plots. Fallows significantly enhanced orb-weavers (Araneidae), sac spiders (Clubionidae) and ground spiders (Gnaphosidae). However, only 4.7% of the total variation in community composition was attributable to fallows. Community variation was larger between landscapes (34.5%) and sites (38.2%). Also β diversity was much higher between landscapes (45 species) and sites (22 species) than between fallows and mown reference plots (10 species). We conclude that the first priority for spider conservation is to preserve as many fen meadows in different landscapes as possible. Locally, rotational fallows enhance overwintering of the above-mentioned spider families, which are sensitive to mowing in other grassland types as well. Thus, rotational fallows would probably foster spider conservation in a wide range of situations. However, stronger effects can be expected from larger and/or older fallow areas.     

Community structure and diversity of bryophytes and vascular plants in abandoned fen meadows

We examined effects of abandonment on species diversity and species composition by comparing 21 calcareous fen meadows in the pre-alpine zone of central and northeastern Switzerland. Meadows were divided into three classes of successional stages (mown: annually mown in late summer, young fallow: 4–15 years, and old fallow: >15 years of abandonment). In each fen, we measured litter mass in four 20 cm×20 cm plots, as well as (aboveground) biomass and species density (number of species per unit area) of bryophytes and vascular plants. Bryophyte biomass was reduced in abandoned fens, whereas litter mass and aboveground biomass of vascular plants increased. Species density of both taxonomic groups was lower in abandoned than in mown fens. Young and old successional stages were not different except for bryophytes, for which old successional stages had higher species density than young stages. We used litter mass and aboveground biomass of vascular plants as covariables in analyses of variance to reveal their effects on species density of both taxonomic groups. For bryophytes, litter mass was more important than vascular plant biomass in explaining variance of species density. This indicates severe effects of burying by litter on bryophyte species density. For species density of vascular plants, both vascular plant biomass and litter mass were of similar importance in explaining the decreased species density. Canonical correspondence analyses showed that abandonment also had an effect on species composition of both bryophytes and vascular plants. However, young and old successional stages were not different indicating fast initial changes after abandonment, but slow secondary succession afterwards. Furthermore, indicator species analysis showed that there was no establishment of new species after abandonment that might dramatically alter fen communities. Re-introduction of mowing as a nature conservation strategy may thus be very promising – even for old fallows.     

Seedling recruitment of Succisella inflexa in fen meadows: Importance of seed and microsite availability

Abstract. 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 longdistance 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.     

Abandonment alters community composition and canopy structure of Swiss calcareous fens

Abstract. We compared the plant species composition, productivity and canopy structure of seven mown sites to a chronosequence of 20 abandoned calcareous fens in northeastern Switzerland. Cessation of mowing led to an 18% decline in overall plant species richness and the diversity of most functional groups. Abandonment did not lead to marked increases of above‐ground productivity, but rather selectively favoured certain functional groups. On abandoned fens biomass of grasses increased nearly threefold, at the expense of biomass of Cyperaceae and Juncaceae, which declined by 30% compared to mown fens, while forb biomass remained unaffected. Litter mass increased more than 15‐fold in fallows, while canopy height increased by 50%. The foliage in abandoned fens was oriented more horizontally and had a lower overall cover. However, these successional changes were never dependent upon the age of the fallow. Furthermore, nearly all traits differed significantly on regional and local spatial scales, suggesting that floristic and (meso‐)climatic differences obscure or override successional trajectories in these species‐rich wetlands.     

Mowing management and density dependence in meadow passerine hatching success

Capsule Improving habitat quality through late or intermittent mowing may increase passerine population density without reducing reproductive success.

Aim To describe the relationship between passerine territory density (TD) and Whinchat Saxicola rubetra and Yellow Wagtail Motacilla flava hatching success, under different management regimes.

Methods TD was defined by the Territory Mapping method in nine sites selected in five French flood plains, in four intermittently mown meadows in Russia and in four additional French sites where mowing was partially postponed. Hatching success was assessed by the observation of prey carrying. Generalized Linear Mixed Models were used to analyse the influence on hatching rates of mowing management, early mowing and TD. Linear Mixed Models were used to study the effect of mowing management on TD.

Results In French early mown meadows, TD affected reproductive success. Higher hatching rates and TD were observed in Russia. Similar results in French study sites with postponed mowing confirmed the influence of mowing management on carrying capacity.

Conclusion In west-European grassland systems, late or intermittently mown patches within or at the edge of meadow areas, with potentially improved invertebrate-prey availability, should help to sustain bird demography and improve the efficiency of current conservation programmes.     

Management of Phragmites australis in Swiss fen meadows by mowing in early summer

Mowing experiments were carried out from1995 to 2001 in Swiss fen meadows toinvestigate whether the abundance of Phragmites australis is reduced by mowingin early summer in addition to mowing inautumn. Experimental plots of 100 m²were established in three fen meadows thatare mown every year in September; treatedplots received an additional cut in lateJune either every year or every two years.Until 1997, the additional cut had noeffect on the above-ground biomass of Phragmites (monitored every year in lateJune). As from 1998, the biomass of Phragmites was 25–30% lower in the plotswith annual June cut than in the controlplots. However, the pooled biomass of allother plant species decreased similarly, sothat the degree of dominance of Phragmites was not reduced. An additionalJune cut every two years had no effect onthe biomass of Phragmites. In June2001, the shoots of Phragmites weresmaller in annually June-cut plots than incontrol plots, but allometric relationshipsbetween shoot length and diameter, shootgrowth from June to August, and nitrogenand phosphorus concentrations of shoots didnot differ between June-cut and controlplots. The additional June cut increasedthe total export of N with the hay by 18%,and that of P by 50% in 2001. Theseadditional nutrient exports were smallerthan those found in the first years of theexperiment and not larger for Phragmites than for the remainder of thevegetation. Together, the results suggestthat a depletion of below-ground storescaused Phragmites to decrease afterseveral years of additional mowing in June.Eighty further permanent quadrats in fenmeadows with normal management (mownannually in September) were surveyed in1995–96 and in 2001. The above-groundbiomass of Phragmites increasedduring this time in 49 out of 80 plots,with a mean relative difference of +35.5%.Thus, even if additional mowing in earlysummer only slightly reduced theperformance of Phragmites compared toplots mown only in September, thistreatment might help to prevent the speciesfrom spreading under the current conditionsin Swiss fen meadows.     

Effects of experimental and real land use on seedling recruitment of six fen species

Seedling emergence and early establishment of six fen species differing in seed mass and growth form were investigated under experimental land use with changed vegetation structure and under real land use in a calcareous fen. Seeds of all six species were sown in plots with different experimental land-use treatments: summer and autumn mowing with or without litter removal, trampling and abandonment. Additionally, emergence and survival of experimentally sown seeds was investigated under real land use on adjacent sites managed by mowing, grazing, intense trampling or abandonment.On abandoned plots and on plots without litter removal of the land-use experiment, emergence rates of all species were negatively affected either by high litter and moss cover or by tall canopy. No differences were found between autumn and summer mowing. Gap creation by experimental trampling did not increase germination rate. Under real land use, establishment of seedlings of most species was positively affected by litter cover and tall canopy. Trampling, in contrast, had a severe negative effect on seedling survival.The investigated species differed in their germination ability which was tested in the germination chamber and in their response to land use. Succisa pratensis with the highest seed mass germinated well in the chamber and in the field more or less regardless of land use. The low germination rate of Parnassia palustris in the germination chamber indicated a limitation of viable seeds. In the field, however, seedling emergence was additionally limited by microsite availability. Seeds of Serratula tinctoria and Primula farinosa germinated well in the germination chamber, but seedling recruitment in the field was hampered in the presence of a high litter or moss cover. Seeds of Tofieldia calyculata and Pinguicula vulgaris were strongly dependent on the availability of suitable microsites in the field. They hardly germinated under natural conditions, in spite of a high number of germinable seeds in the germination chamber.     

Effects of habitat fragmentation on the fitness of two common wetland species,Carex davalliana and Succisa pratensis

Small habitat size and spatial isolation may cause plant populations to suffer from genetic drift and inbreeding, leading to a reduced fitness of individual plants. We examined the germination, establishment, growth, and reproductive capacity of two characteristic species of mown fen meadows, Carex davalliana, and Succisa pratensis, common in Switzerland. Plants were grown from seeds, which were collected in 18 habitat islands, differing in size and in degree of isolation. We used both common garden and reciprocal transplant experiments to assess effects of habitat fragmentation. In the common garden, plants of Carex originating from small habitat islands yielded 35% less biomass, 30% fewer tillers, and 45% fewer flowering tillers than plants from larger ones. In contrast, plants of Succisa originating from small habitat islands yielded 19% more biomass, 14% more flower heads and 35% more flowers per flower head than plants from larger ones. Moreover, plants of Succisa from small isolated habitats yielded 32% more rosettes than did plants from small connected islands. Reciprocally transplanted plants of Succisa originating from small habitat islands produced 7% more rosettes than plants from larger ones. There was no effect of small habitat size and isolation on germination and establishment of both species in the field. Our results document genetic differences in performance attributable to habitat fragmentation in both species. We suggest that fitness loss in Carex is caused by inbreeding depression, whereas in Succisa the differences in fitness are more likely caused by genetic differentiation. Our study implies that habitat fragmentation affects common habitat-specific species, such as Carex and Succisa, as well as rare ones.     

Restorative mowing on an abandoned semi‐natural meadow: short‐term and predicted long‐term effects

Abstract. When management, in the form of cattle grazing and mowing, ceases the abundance of competitively superior plant species tends to increase in abandoned semi‐natural meadows. Litter accumulation elevates the soil nutrient levels and hinders seedling recruitment. We surveyed changes in plant cover and species composition of a formerly grazed meadow in permanent plots for six years. Some plots were unmown, while others were mown and raked annually in August. The cover of grasses decreased and herb cover remained unchanged regardless of the treatment. Mowing and raking significantly reduced litter accumulation and increased the number of ground layer species. The expected long‐term effects of abandonment and restorative mowing were studied by calculating the transition probabilities for unmown and mown plots and simulating the course of succession as projected by the transition matrices. During a simulation period of 30 yr, abandonment led to (1) a decrease in the cover of small herbs, (2) a slight increase in the cover of tall herbs and (3) a slight decrease in the cover of grasses. In contrast, the cover of small herbs on the mown plots remained unchanged or slightly increased during the course of simulation. These results suggest that mowing late in the season is primarily a management tool for the maintenance of the existing species diversity and composition. However, it may not be an effective restorative tool to induce overall changes in the resident vegetation of abandoned grass‐dominated meadows. Grazing or mowing early in the season may be more effective in this respect. Consequently, mowing early or, alternatively, late in the season may provide management strategies for the maintenance and restoration of species diversity, respectively.     

Reinforced Traditional Management is Needed to Save a Declining Meadow Species. A Demographic Analysis

The changes in agricultural practices during the last century have led to a drastic decrease in the number of traditionally managed hay meadows. Also, traditional management practices are often applied more cursorily in the remaining meadows. In combination with an increase in aerial anthropogenic nitrogen deposition, this has led to a loss of biodiversity. To investigate whether the current management is sufficient for maintaining viable populations of a typical meadow plant, Succisa pratensis, we experimentally reinforced the raking and mowing parts of the traditional management over four years in a two-by-two factorial experiment in three traditionally managed wooded hay meadows on the Baltic island of Gotland, Sweden. We found decreased litter and hay production in two of the three studied meadows as a result of our treatments. Plant sizes and asymptotic population growth rates (??) of S. pratensis increased, particularly in plots receiving the combined raking and mowing treatment. Stochastic long-term population growth rates (?? _s ) increased under the reinforced management: projected population sizes 50?years into the future showed a three-fold increase in raked plots and a 17-fold increase in plots that were both raked and mown. Because we found positive responses even in these seemingly well-managed meadows we conclude that it is essential that management is carried out more thoroughly to ensure viable population sizes. Our conclusion applies to most semi-natural grasslands receiving anthropogenic nitrogen, or where traditional management practices are less rigorously applied. We also suggest using biomass estimation instead of vegetation height as a measure of management strength.     

Clonal ability,height and growth form explain species’ response to habitat deterioration in Fennoscandian wooded meadows

Fennoscandian calcareous wooded meadows have high conservation value due to very high diversity which has been maintained by consistent mowing, but undergo species loss when this management is abandoned. We compared species richness and composition of regularly mown and abandoned wooded meadows in Estonia and established species groups with respect to their response to abandonment. These meadows were very species rich with a maximum of 43 species per 0.25 m². Species whose populations are maintained by mowing constituted >60 % of the floristic diversity of the mown wooded meadows. Abandonment suppressed species with a preference for dry infertile open habitats. Response to abandonment was related to clonality, height and growth form. The greatest negative response was associated with low graminoids, short-lived and non-clonal species, rosette and semi-rosette growth form. Weak competitors with low height and light seeds exhibited a slow decline; perennial life span and clonality enable a delay in local extinction of these species. Response groups had similar persistence at a national level, revealing that earlier assessment of species dynamics at larger spatial scales could underestimate the number of threatened species. Application of restoration measures could avoid local extinctions of many mowing-supported species, whereas some of the mowing-dependent species likely need reintroduction.     

Population structure of the threatened perennial Serratula tinctoria in relation to vegetation and management

Question: How does vegetation and management affect the population stage structure of Serratula tinctoria, a species indicative of highly endangered and species‐rich flood‐plain meadows? Are different management regimes suitable to support viable populations of S. tinctoria? Location: Flood‐plain of the northern Upper Rhine, Germany. Methods: We analysed the population structure of S. tinctoria at 24 meadow sites which differed in vegetation and management. In this comparative study the investigated meadows were either (1) late mown in September; (2) early mown in June or (3) mown in June and then grazed by sheep. Results: The structure of the surrounding vegetation had a clear effect on the population structure of S. tinctoria. The percentage of bare soil, as well as the cover of bryophytes, were positively related, whereas the Ellenberg N‐value of the established vegetation was negatively related to the density and proportion of seedlings. Generally, we found only slight differences between the population structure of S. tinctoria in early and late mown meadows. Both management regimes had high densities of seedlings. In contrast, the meadow pastures supported significantly lower densities of seedlings and generative adults but relatively high densities of juveniles and vegetative adults, indicating a greater importance of clonal propagation under grazing pressure. Conclusions: Our results clearly showed that viable populations of S. tinctoria may occur in all of the studied management regimes. Although S. tinctoria was considered to be highly sensitive to early mowing, our findings suggest a facilitation of the species at more nutrient‐rich sites by mowing in June, which is also a benefit for the integration of management in farming systems.     

How do management and restoration needs of mountain grasslands depend on moisture regime? Experimental study from north‐western Slovakia (Western Carpathians)

Question: How does species composition change in traditionally managed meadows after mowing has ceased, and in abandoned meadows after re‐introduction of mowing? Are there differences in the dynamics of dry and moderately wet meadows? Location: Zázrivá‐Ple?ivá (19°11′N, 49°16′E), north‐western Slovakia, western Carpathians. Methods: Pairs of experimental plots (mown and unmown) were established to replicate each combination of dry/wet and traditionally managed/abandoned meadows. Changes in species composition were studied over 5 years. The data on changes in species composition was analysed by constrained and unconstrained ordinations, and visualized using Principal Response Curves. Results: Species composition of newly abandoned wet grasslands was changing towards the corresponding long‐abandoned plots even in the first year of abandonment. Similarly, newly established restoration mowing in abandoned dry grasslands rapidly shifted the stand species composition towards that of traditionally managed ones. Nevertheless, 4 year after reintroduction of mowing, the species composition of the restored plots was still far from the target composition. The effect of mowing in abandoned wet grasslands and abandonment in dry grasslands was much less pronounced and slower. Conclusions: Moisture regime is a very important factor determining the management needs of various grassland types. Wet grasslands are much more sensitive to abandonment, with a rapid degradation rate and limited possibilities for restoration, which can be extremely slow. Even in the dry grasslands, that quickly responded to restoration mowing, restoration is a long‐term process.     

The effects of mowing and fertilization on carbohydrate reserves and regrowth of grasses: do they promote plant coexistence in species-rich meadows?

After the cessation of regular management and after fertilization a single clonal species tends to dominate in many types of grasslands, whereas in regularly managed meadows these potential dominants usually attain a low cover. It has been hypothesized that plants reaching a high dominance in abandoned and fertilized meadows are selectively suppressed by mowing so that a balanced competition is maintained and competitive exclusion is postponed. We compared regeneration capacity and carbohydrate reserves accumulated by three species of clonal grasses, which markedly increase their dominance in irregularly mown, un-mown or fertilized meadows. Above-ground biomass and the amount of storage carbohydrates of the two largest species, (Molinia arundinacea, Calamagrostis epigejos) were reduced in a mown meadow. This effect was weaker in Bromus erectus, which produces smaller shoots. Shoots of Molinia were most impacted by mowing but their regeneration was efficient due to the large carbohydrate reserves in the shoot bases. Fertilization did not affect Bromus and Calamagrostis. In contrast, fertilized plants of Molinia produced larger storage organs and accumulated more carbohydrates. We conclude that plant size and growth form are important features promoting the ability of potential dominants to tolerate mowing and regenerate after it. Our results confirm that taller plants are selectively suppressed by this type of disturbance, thereby potentially promoting plant coexistence.     

Morphology and phenology of Scabiosa columbaria from mown and grazed habitats - Results of a simulation experiment

We analysed the morphology and phenology of Scabiosa columbaria in relation to grassland management by mowing and grazing. We selected 12 populations from mown and grazed calcareous grassland in six regions of central Europe. At each population site, we collected seed material to produce plants for a morphological and phenological analysis of the species in a simulation experiment, which comprised three treatments (control, simulated mowing and simulated grazing).The simulation experiment revealed a clear morphological and phenological differentiation of S. columbaria. Plants from the two treatment types differed in size, since individuals from mown sites had longer top peduncles than individuals from grazed sites. Individuals from mown populations flowered earlier than individuals from grazed populations. In the control treatment, individuals from both habitat types produced a similar number of fruiting capitulums. When subjected to simulated mowing, the reproductive success of the individuals was clearly reduced. Plants from mown habitats produced, however, a significantly larger number of fruiting capitulums than plants from grazed habitats. Simulated grazing reduced the reproductive success stronger than simulated mowing but differences between individuals from both habitat types were not significant.The results of our simulation experiment clearly indicate morphological and phenological adaptation of S. columbaria to mowing and grazing. The comparatively young selection pressure of mowing obviously selected early flowering individuals, while the original land use by grazing favoured late flowering plants.     

Factors Affecting Seed Germination and Seedling Establishment of Fen-Meadow Species

Availability of seeds and provision of “safe sites” for seedling recruitment are essential for successful restoration of seminatural grassland communities. Inability to provide species‐specific conditions for seedling recruitment appears to be a major factor limiting establishment of fen‐meadow species on restoration sites. This contention was tested in the field for both germination and establishment conditions for a selection of fen‐meadow species. A Cirsio‐Molinietum fen meadow and an agriculturally semi‐improved species‐poor grass dominated rush pasture were used. Seeds of Carex ovalis, Cirsium dissectum, Molinia caerulea, Succisa pratensis, and Holcus lanatus were sown onto treatments comprising either irrigation or no irrigation, presence or absence of existing vegetation canopy, and presence or absence of soil disturbance. Germination of all except H. lanatus was higher in the fen meadow than in the rush pasture. The fen‐meadow site was less susceptible to drought, provided more light to the seed environment, and showed a stronger day–night variation in relative humidity compared with the rush pasture. All the fen‐meadow species responded strongly to the experimental treatments, whereas H. lanatus showed only a small response. Soil disturbance was the major factor that increased germination. Removal of the vegetation canopy improved germination only in S. pratensis. Conditions affecting survival of seedlings were different from those affecting seed germination. Seedling survival was greater on the fen‐meadow site than on the rush pasture. Canopy presence was the major factor that reduced seedling survival. Few seedlings survived in the presence of the rush pasture canopy. Irrigation and soil disturbance were of minor importance for seedling survival on both sites. Safe sites for seed germination and seedling establishment of fen‐meadow species existed on the fen meadow even without soil disturbance and gap creation. Safe sites for seedling recruitment were not present in the rush pasture. The need for species‐specific definition of safe site characteristics at the two stages of seedling recruitment (i.e., for seed germination and for seedling survival) was demonstrated. The implications of these findings for restoration of seminatural grasslands are discussed.     

Bottlenecks and spatiotemporal variation in the sexual reproduction pathway of perennial meadow plants

Sexual reproduction is important for the growth of populations and the maintenance of genetic diversity. Several steps are involved in the sexual reproduction pathway of plants: the production of flowers, the production of seeds and the establishment of seedlings from seeds. In this paper we quantify the relative importance and spatiotemporal variability of these different steps for four grassland perennials: Centaurea jacea, Cirsium dissectum, Hypochaeris radicata and Succisa pratensis. We compared undisturbed meadows with meadows where the top soil layer had been removed as a restoration measure. Data on the number of flower heads per flowering rosette, the numbers of flowers and seeds per flower head, and the seedling establishment probabilities per seed were collected by field observations and experiments in several sites and years. Combination of these data shows that H. radicata and S. pratensis have higher recruitment rates (1.9 and 3.3 seedlings per year per flowering rosette, respectively) than the more clonal C. dissectum and C. jacea (0.027 and 0.23, respectively). Seedling establishment is the major bottleneck for successful sexual reproduction in all species. Large losses also occurred due to failing seed set in C. dissectum. Comparison of the coefficients of variation per step in space and time revealed that spatiotemporal variability was largest in seedling establishment, followed closely by flower head production and seed set.     

Influence of management on the seed production and seed bank of calcareous fen species

Abstract. The dynamics of the seed production and seed bank of two dominant perennial species of calcareous fens were investigated in response to different mowing frequency, fallow or pasture. The production of fertile shoots responded strongly to management practices. On sites where mowing alternated with fallow, autumn mowing led to an increase of fertile shoot density in Schoenus ferrugineus and a decrease in Molinia caerulea in the subsequent season. Repeated annual mowing after long-term fallow raised the density in Schoenus and inhibited initiation of flowering shoots in Molinia. Seed set and viability were influenced mainly by climatic or other factors. Variation of seed production between sites and in consecutive years at the same site could thus be large. The relationship between total seed production and seed bank was weak, but it improved when germination rates were included in the calculation. As the seed bank was generally smaller than the viable seed production, low survival and a high turnover of seeds in the upper soil layers is assumed for both species. Implications for recruitment strategies are discussed.     

Land use affects flowering time: seasonal and genetic differentiation in the grassland plant Scabiosa columbaria

Management practices like mowing or grazing have a large impact on grassland species. Due to its evolutionary significance, the interaction between the flowering time of plants and land use is of special interest. Asynchronous flowering restricts gene flow between populations and promotes, as a consequence, their differentiation. We selected 12 populations across southern central Europe to study the impact of mowing and grazing on seasonal and genetic differentiation in the grassland species Scabiosa columbaria. We conducted a common garden experiment to analyse floral display between populations and applied molecular markers to assess genetic diversity and genetic differentiation between populations. We demonstrated explicitly that flowering time and genetic differentiation are linked with the type of land use. Populations from mown habitats flowered significantly earlier than populations from grazed sites. Furthermore, genetic differentiation was stronger between populations from sites of different land use than between populations from far away geographic regions. The results of this study indicate that populations of S. columbaria are seasonally adapted to mowing and grazing. Land use is, therefore, an important factor for evolution in grassland species, which promotes the development of seasonal ecotypes and clearly affects intraspecific variation.