The impact of cutting,liming and fertilizing on characteristics of abandoned upland meadows in the Czech Republic

The responses of three upland grassland phytocoenoses to three different management treatments were studied in Southern Bohemia. The sites were at an advanced successional stage, with all three being meadows abandoned since World War II: (i) Molinion, (ii) degraded Calthion with dominant Carex brizoides and (iii) plant community with the dominant species Calamagrostis villosa. Three different treatments (cutting, liming and fertilizing) were applied to the three grassland types, and their effects on the diversity, plant cover and biomass production were investigated over a 3‐year period. Analyses showed significant differences between meadow types in time as well as response to treatments. Independent of the treatments, the biomass production and Shannon index increased significantly in all meadows by varying degrees during the investigation period, whereas the cover decreased slightly in the case of the Carex community and the Molinion and remained unchanged in the case of the Calamagrostis community. Changes in the ground cover (as percentage) in response to management treatments varied between the meadow types. Limed and fertilized plots of the Molinion and Calamagrostis communities had higher percentage cover values compared to the control, but the cover of the C. brizoides community was not affected. In contrast, cut plots of the Molinion had slightly reduced cover. The changes in biomass and species diversity showed no significant correlation with the types of treatment used.     

Cutting frequency vs. N application: effect of a 20‐year management in Lolio‐Cynosuretum grassland

The aim of this study was to determine the effects of different long‐term management options on re‐establishment of traditional species‐rich grassland in a Lolio‐Cynosuretum grassland. The experiment was set up in 1987 in a low‐fertilized mown pasture in the Eifel Mountains (Germany). Two and four cuts per year each with three levels of nitrogen fertilizer application were compared to no application of P and K fertilizer. Biomass production increased as a result of N application, whereas crude protein content and digestibility of organic matter improved in the four‐cut treatments. During a 20‐year period, we found a significant shift in dominant grass species without any significant effect on species richness. Lolium perenne and Elytrigia repens were replaced by Holcus lanatus and Alopecurus pratensis, especially in the two‐cut treatments with N application. In the unfertilized plots, several individuals of Platanthera bifolia appeared when swards were cut only twice per year, probably as a result of nutrient depletion together with low cutting frequency. An increase in number of cuts mainly supported plant species well adapted to intensive management, even under low N application and relatively low plant‐available P content in the soil. Therefore, we conclude that cutting frequency was a key driver on plant species composition in this experiment. The re‐establishment of traditional species‐rich grassland from intensively managed Lolio‐Cynosuretum was not achieved within 20 years of cutting management combined with absence of P and K application.     

Seasonal productivity and nutritive value of temperate grasses found in semi-natural pastures in Europe: responses to cutting frequency and N supply

Monocultures of thirteen perennial C₃ grass species that co‐occur in temperate semi‐natural grassland communities in Europe were compared in a factorial field design of two levels of N supply and two levels of cutting frequency. Above‐ground yield of dry matter (DM), crude protein (CP) concentration and pepsin‐cellulase DM digestibility of herbage were measured in two successive years. Species was the largest source of variability in yield of DM and DM digestibility of herbage, while CP concentration of herbage responded more to management factors. The highest mean DM yields and values of DM digestibility of herbage were achieved in spring for Festuca arundinacea and in autumn for Phleum pratense. Poa trivialis and Festuca rubra had the lowest DM yield and DM digestibility values, respectively, regardless of seasons and treatments. For all species CP concentration in herbage increased in response to an increase in cutting frequency and N supply by an average of 46 and 34 g kg^?1 DM respectively. Differences between years and seasons indicated the importance of plant phenology on nutritional variables and the influence of environmental factors on species performance. Species ranking was compared according to their annual digestible DM and CP yields. The results show that some grasses have a nutritive value which is comparable to that of forages selected for high yields.     

Seed production in grassland species: Morpho‐biological determinants in a species‐rich semi‐natural grassland

Studying the seed production of herbaceous species can help to conserve grassland habitats and re‐create new high‐value grassland surfaces. Studies on grassland seed production have focused mainly on individual species and traits, without characterizing their relative importance at the plant community level. The aim of this study was to investigate the entire seed production process of the main species in a temperate grassland. Fertile shoots (FS) of twenty‐nine grasses and forbs were collected over 4 years and analysed for sixteen traits that determine inflorescence size, seed production and seed quality. The per cent viability played a predominant role in determining the total production of viable seeds. Forbs showed a range of reproductive strategies, including variable distribution of flowers among growth periods, number of inflorescences per FS and relationship between seed size and FS density in the grassland. The flower production for grasses was concentrated in the first growth period, but this limitation was mitigated by a higher seed dormancy. The number of viable seeds per FS and seed size were important components of the reproductive strategy of forbs, with heavy‐seeded species being characterised by high individual densities in the community, but producing few seeds per FS. Light‐seeded species showed an opposite pattern. The results suggest that when using seeds from semi‐natural grasslands for ecological restoration, special attention should be paid to the seed amount, germinability and viability of forbs, as they seem to depend more on seed reproduction and have a lower ovule to seed transformation efficiency.     

Effects of pasture management and fertilizer regimes on botanical changes in species‐rich mountain calcareous grassland in Central Europe

A 3‐year experiment was conducted in Central Europe to examine the effects of three managements, viz. continuous cattle grazing from April to September, mowing once in July and abandonment of grazing, and two levels of fertilizer application, no fertilizer and 400 kg ha^?1 of a NPK fertilizer, on changes in plant species composition and summer biomass of dry matter (DM) in a calcareous mountain grassland containing many plant functional types. Different managements led to changes in species composition due to species‐specific responses. Low creeping and rosette species were associated with grazing, while grasses and tall forbs correlated with mowing and abandonment of grazing, probably because of their ability to outcompete rosette species. There was a negative relationship between the number of species and above‐ground biomass and a positive relationship between number of species and below‐ground biomass, suggesting that these species‐rich communities allocate more to below‐ground organs when not grazed. The application of fertilizer had no effect on species composition but it indirectly increased competitive asymmetry for light and increased the number of plant extinctions. It is concluded that continuation of cattle grazing is an acceptable form of grassland management at the study site and that species and functional group compositions can rapidly change with changing environmental conditions such as abandonment of grazing or application of fertilizer.     

Long‐term effects of mulching,traditional cutting and no management on plant species composition of improved upland grassland in the Czech Republic

A shortage of available livestock for utilizing grassland biomass in Central Europe is challenging for the management of both semi‐natural grasslands and previously intensified (limed, fertilized and reseeded) upland grasslands. An alternative method of grassland management is mulching, in which aboveground biomass is cut, crushed and subsequently spread on the surface. This paper reports on an experiment to compare three different mulching frequencies (one, two and three times per year) with an unmanaged treatment and traditional management of two cuts per year (control) on a previously improved upland meadow. Plant species composition was monitored over 13 years. Traditional management of two cuts with biomass removal was the most suitable method for maintaining plant species richness and diversity, and both were reduced significantly in the once‐mulched and especially in the unmanaged treatment. Tall dicotyledonous weeds such as Urtica dioica, Cirsium arvense and Aegopodium podagraria were promoted by the unmanaged treatment and by mulching once a year. Higher frequency of defoliation had positive effects on the spread of short forbs such as Taraxacum spp., Plantago lanceolata and Trifolium repens. After eight years, there were changes in sward structure in the unmanaged and mulched‐once‐a‐year treatments, with increase in the tall/short species ratio. In conclusion, repeated mulching cannot substitute fully for traditional two‐cut management in improved upland meadows without decreasing plant species richness and diversity, and changing the sward structure. Although mulching once a year may prevent invasion by shrubs and trees, it also supports the spread of weedy species similar to no management.     

Grasslands in ‘Old World’ and ‘New World’ Mediterranean‐climate zones: past trends,current status and future research priorities

Despite their ecological, economic and social importance, grasslands in areas with Mediterranean climates continue to receive limited scientific, political and media attention. The main objectives of this review are to compare and contrast dryland grasslands in the ‘Old World’ regions of the Mediterranean basin (southern Europe, western Asia and North Africa) with those of ‘New World’ regions with Mediterranean climates (Australia and Chile) and to identify common research priorities. The common characteristics and differences in climate, soils, native vegetation, importance of the livestock sector and the socio‐economic background for the different Mediterranean environments are examined. Past trends and the current status of temporary and permanent Mediterranean grasslands are also described. Some common issues between these regions are as follows: (i) adaptation to climate change; (ii) increasing persistence and drought survival of both annual and perennial species; (iii) the important role of forage legumes; (iv) maintaining grassland plant diversity; and (v) improved ecosystem services, such as carbon sequestration, control of soil erosion and wildfires, and preservation of both wild and domestic biodiversity. The favourable climate in these regions, which allows year‐round grazing and the growth of legumes, should be exploited to improve the sustainability of grassland‐based, extensive farming systems and the quality of their animal products, while at the same time improving ecosystem services. The decreasing support for grassland research and development programmes requires increased international scientific and technical cooperation among the few institutions operating in the different Mediterranean‐climate areas of the World to provide innovative and sustainable solutions to farmers.     

Reintroduction of grazing management after deforestation of formerly abandoned grassland and its effect on early vegetation changes in the Western Carpathians (Slovakia)

Although the process of reforestation of grassland has been widely studied in Europe, little is known about the effect of deforestation on grassland development. Thus, the specific objective of this study was to evaluate early changes in plant species composition, functional group, yield and biomass quality after deforestation of long‐term abandoned pastures. The experiment was established immediately after deforestation on sparse herbaceous vegetation (mean initial cover 27%) with the following treatments: grazing management only (G0), cutting and grazing aftermath (CG), grazing after seeding of grassland mixture (GS), grazing after a burning treatment in which branches were burned after deforestation (GB) and unmanaged control (U). Very rapid recovery of bare ground by germination and/or sprouting of grassland species was similar under all types of grazing management. Total plant species richness increased in all managed treatments except GB. Similarities according to redundancy analyses in plant species composition were found among G0, CG and GB treatments, especially for forbs with correlated rosette or creeping growth. The woody species, tall grasses and tall forbs had higher abundance in the U treatment. The restoration of grassland following deforestation of formerly reforested grassland area by grazing management was a relatively fast process, and swards were created after 3 years. The highest biomass yield was observed under treatments GS and GB. Forage quality of all managed treatments was sufficient for the demands of beef cattle grazing. However, for subsequent grassland preservation, some type of grazing management is necessary to prevent reforestation, which can occur immediately after deforestation in unmanaged places.     

Asymmetric relationship between grasses and forbs: results from a field experiment under nutrient limitation

We compared the role of grasses and forbs in managed grassland under nutrient‐poor conditions via the experimental removal of one of these two species groups and an evaluation of the removal effects over a 5‐year chronosequence (beginning 4 years after removal start), focusing on above‐ground biomass and community composition. There was evidence for the complementarity of grasses and forbs, as shown by better relative performance of both groups in the mixture, measured as the proportional deviation of their above‐ground biomass from that predicted using single‐group plots. Relative performance of forbs was better than that of grasses and did not change significantly throughout the experiment. Relative performance of grasses decreased, reaching a minimum value of 0·03, but then increased to 0·71, in parallel with increasing legume proportion in the above‐ground biomass (from 0·9 to 5·1%). The botanical composition of the grass group did not respond to forb removal. Among the forbs, subordinate species sensitive to light competition became more abundant after removal of grasses; the forb species richness increased on average by 1·6 species per plot. Our results show that the composition and diversity of the forb group is affected by the presence of grasses, and the presence of forbs in a grassland community assures higher temporal stability in above‐ground production. Under increasing depletion of soil nutrients, the grasses derive substantial benefits from the presence of legume species and possibly also from the other forb species. The study supports the need for realistic, long‐term experiments to better understand plant community dynamics.     

A methodology for characterization and analysis of plant functional composition in grassland‐based farms

Understanding the relationships between farmers' land‐use and management decisions, and plant diversity is a challenge. It requires characterization of plant diversity within and between fields and investigation of land‐use allocation to fields. To analyse how grassland functional composition [mean plant trait and functional diversity index (FD)] varies according to scale (field, land‐use type: cutting, grazing, farm), grasslands were characterized according to leaf dry‐matter content (leaf DM) and FD computed from leaf DM values. A leaf DM‐αFD framework was used to analyse how leaf DM‐based plant strategies were distributed at land‐use type and farm scales (βFD). The study was conducted on eight dairy and beef farms (169 grasslands) differing in their stocking rate. At field and land‐use type scales, leaf DM was significantly decreased and increased with N fertilizer rate and field elevation respectively. It was significantly higher for grazing than for cutting. At the farm scale, the main differences between farms resulted from differences in plant strategy distribution between land‐use types within a farm and among farms for a given land‐use type in relation to management intensity. Farms that contributed the most to αFD had the highest stocking rate, and those which had the most contrasting grasslands for management intensity had the highest βFD. Management practices need to be examined at a land‐use type scale for evaluating the within‐ and between‐field plant functional compositions. By contrast, the value of the analysis was reduced if data were collected and averaged at the farm scale.     

Effects of nitrogen fertilization and cutting intensity on the agronomic performance of warm‐season grasses

Responses of grasses to N fertilization are affected by cutting intensity although little is known regarding the interactions of these factors in warm‐season grasses. Pre‐cutting canopy height, herbage accumulation and changes in the nutritive value of warm‐season grasses in response to four different management strategies were assessed from October 2011 to September 2014. Treatments included two cutting intensities (70 vs. 50% depletion of canopy height set by 95% light interception), two N fertilization levels (zero vs. 300 kg N ha^?1 year^?1) and six perennial C₄ grass species (Axonopus catharinensis; Cynodon spp. hybrid Tifton 85; Hemarthria altissima cv. Flórida; Megathyrsus maximus cv. Aruana; Paspalum notatum cv. Pensacola; and Urochloa brizantha cv. Marandu) grown in monoculture in a factorial experimental design. Canopy height varied among grass species, cutting intensity and N treatments, mainly among seasons, indicating that more than one management target (i.e. canopy height) existed throughout the plant growth cycle for each species. The largest herbage accumulation occurred in the N fertilization treatments for most species, regardless of cutting intensity. Nitrogen fertilization and 50% depletion of canopy height increased the leaf proportion and decreased the neutral detergent fibre content. Overall, N fertilization had a stronger positive impact than cutting intensity on the acid detergent fibre content, dry‐matter digestibility and crude protein content, but the magnitudes of the responses were species‐specific.     

Plant functional traits and nutrient gradients on grassland

The traditional way of interpreting environmental and management effects on floristic composition based on phyto‐sociological classification is increasingly accompanied by a trait‐based approach. Plant functional traits (PFT) enable us to link morphological, physiological and phenological plant properties to their functions. Recent research on PFT has significantly improved our understanding on competitive ability of species, resulting species abundance and ecosystem functioning, through investigations of ecological strategies, community assembly theory and functional diversity. In this paper, we review the wide applicability of the trait approach in grassland science. The paper summarizes the power of PFT, the variation along soil nutrient gradients, and gives a case‐by‐case conceptual generalization of mechanisms of interacting traits at plant and canopy scale. We highlight the main trade‐offs among traits and trait syndromes that are prospects for plant response to nutrient gradient and consequently for ecosystem processes. We also discuss the role of intraspecific variability in PFT for multiple ecological issues. Links between functional ecology and grassland science are also identified in order to establish research opportunities. For managed grasslands, we believe that progress in these links will allow us to address broad and timely questions regarding community dynamics driven by resource availability and the consequent multifunctionality of these grasslands.     

Species interactions in a grassland mixture under low nitrogen fertilization and two cutting frequencies: 1. dry‐matter yield and dynamics of species composition

Four‐species mixtures and pure stands of perennial ryegrass, tall fescue, white clover and red clover were grown in three‐cut and five‐cut systems at Ås, southern Norway, at a low fertilization rate (100 kg N ha^?1 year^?1). Over a three‐year experiment, we found strong positive effects of species diversity on annual dry‐matter yield and yield stability under both cutting frequencies. The overyielding in mixtures relative to pure stands was highest in the five‐cut system and in the second year. Among the possible pairwise species interaction effects contributing to the diversity effect, the grass–grass interaction was the strongest, being significant in both cutting systems and in all years. The grass–legume interactions were sometimes significant, but no significant legume–legume interaction could be detected. Competitive relationships between species varied from year to year and also between cutting systems. Estimations based on species identity effects and pair‐specific interactions suggested that the optimal proportions of red clover, white clover, perennial ryegrass and tall fescue in seed mixtures would have been around 0·1, 0·2, 0·4 and 0·3 in the three‐cut system, and 0·1, 0·3, 0·3 and 0·3 in the five‐cut system.     

Influence of cutting regime and fertilizer application on the botanical composition,yield and nutritive value of herbage of wet grasslands in Central Europe

The changes in dry matter (DM) yield, botanical composition and nutritive value of herbage to ruminants of two wet grasslands, Arrhenatherum elatius grassland (Experiment 1) and a Molinia caerulea fen meadow (Experiment 2), in which a range of cutting and fertilizer treatments were imposed in 1999, were assessed after 4–7 years of treatment imposition. Both experiments had a split‐plot design with four replicates. In Experiment 1 the three main‐plot cutting treatments were two cuts with a delayed first cut, three cuts and four cuts during the growing season of each year. In Experiment 2 the cutting treatments were two cuts with a traditional harvest time, two cuts with a delayed first cut and three cuts. The four sub‐plot fertilizer treatments were an unfertilized control, application of a phosphorus and potassium (PK) fertilizer, application of a nitrogen (N) and PK fertilizer to the first cut only (N₁PK) and application of PK plus N applied to each of two, three or four cuts (N_c PK). Application of fertilizer influenced yield and botanical composition of herbage more than the cutting treatments while the opposite occurred for nutritive value of the herbage. Application of fertilizer increased the proportion of tall grasses in Experiment 1 and forbs in Experiment 2. The proportion of Equisetum palustre, present only in Experiment 1, was reduced from 0·33 to less than 0·01 by increased cutting frequency together with the NPK fertilizer treatments. In Experiment 1 diversity of vascular plants was negatively affected only by the four‐cuts treatment while on both wet grasslands other cutting and fertilizer application treatments had no effect. Changes in DM yield of herbage caused by the cutting and fertilizer application treatments were similar for both vegetation types with DM yield increased significantly by fertilizer application but only slightly or not reduced by increasing the cutting frequency. Nutritive value of herbage was positively correlated with cutting frequency and was most influenced at the first cut.     

The conservation management of mesotrophic (meadow) grassland in Northern England. 2. Effects of grazing, cutting date, fertilizer and seed application on the vegetation of an agriculturally improved sward

The plant species number and composition, iind yield of herbage biomass of an agriculturally improved hay meadow were assessed after 4 years under various combinations of grazing, fertilizer applicution. cutting date and seed addition treatments in a replicated split-plot design. Grazing treatments consisted of either autumn grazing with cattle and sheep, spring grazing with sheep or both regimes. Fertilizer application treatments consisted of either 25 kg ha^?1 N plus 12–5 kg ha^?1 P and K or no fertilizer. Cutting date treatments consisted of cuts on either 14 June, 2i July or 1 September. Seed addition treatments consisted of either no addition or sowing with a range of meadow species in the autumn. Data analysis was by correspondence analysis and analysis of variance. Species number decreased with fenilizer use and when the cutting date was 1 September. A range of species was affected by the main treatments and there were some first-order interactions, mainly between cutting date and fertilizer application. Rhinanthus minor was particularly favoured by the seed addition treatment. Species attnbutes in the regenerative and established phase were related to treatments and their effect on species composition. The National Vegetation Classification communities were associated with particular treatment regimes. The 21 July cutting date favoured ‘improved’ over ‘unimproved-traditional’ swards, with spring grazing favouring ‘unimproved-traditional’ swards. Lowest yields of herbage biomass were associated with autumn and spring grazing, the 14 June cutting date and no fenilizer treatments. The fenil-izer, 1 September cutting date and auiumn grazing treatments gave the highest yields. The implications of these results are discussed in terms of the conservation management required to return agriculturally improved mesotrophic grassland to a species composition similarto that of traditionally managed grassland.     

Sustainable,low‐input,warm‐season,grass–legume grassland mixtures: mission (nearly) impossible?

Grazing lands in warm‐temperate and subtropical North America have become less diverse. Pastures are typically grass monocultures, while rangelands are generally managed for the grass components. Overstocking, selective herbicides, fire exclusion and heavy rates of nitrogen fertilizer have contributed to near exclusion of native, warm‐season legumes. The simplicity of managing grass monocultures, pasture production responses to nitrogen fertilizer and profitability of grass‐only systems have limited interest in legume‐based approaches. Changing economics and ecological concerns with ecosystem accumulation of industrial inputs contribute to an increasing interest in legumes. Unlike the development of temperate pasture legumes and recent research in the tropics, legumes tolerant of both freezing temperatures and hot weather have received less attention. Poor establishment, limited persistence and potential invasiveness limit currently available introduced species. Native, herbaceous, warm‐season legume species occur throughout warm‐temperate North America, but little attention has been directed to these plants as potential forage species. Some success with a few native legume species, primarily in the genus Desmanthus, suggests potential for expanded assessment of forage value of the many species available. Current assessments of native legumes, primarily for conservation purposes, provide an opportunity to expand evaluations of these species for pasture and rangeland potential while economics of livestock production and public interest in ecosystem health are supportive. Experiences with legumes of warm‐temperate origin in North America, along with results with temperate and tropical pasture legumes globally, provide a starting point for future efforts at incorporating greater legume diversity in pastures and rangelands of subtropical and warm‐temperate regions around the world.     

文昌8个森林群落结构与物种多样性研究

以文昌航天发射缓冲区不同森林群落为研究对象,选择8个不同植被类型,分别设置1 hm2固定大样地,对森林植物群落的多样性、森林植物群落的物种均匀度、森林植物群落的物种优势度进行观测。结果表明：不同森林群落乔木层物种多样性差异显著,半红树林群落树种种类最高,物种多样性最高达到2.38,其次分别是天然次生林和人工混交林;不同森林群落中不同层次植物均匀度总体表现出草本层＞灌木层＞乔木层的规律,但天然次生林由于郁闭度较高,林下草本较灌木少,多样性和均匀度均小于灌木层;红树林物种优势度最小,各物种优势差异不显著。     

Effects of species aggregation, habitat and season on the accuracy of double-sampling to measure herbage mass in a lowland grassland ecosystem

Double‐sampling, as a cost‐effective and sufficiently accurate method, is an acknowledged method for estimating herbage mass at the level of the plant species up to the total plant community. It was investigated whether adjusting visual estimations of double‐sampling is applicable at different levels of species aggregation when different seasons and habitats are involved. The method was used in six different habitats of the same ecosystem, a grassland nature reserve in western Belgium, based on eight sampling periods. A general linear model was used to analyse the data at four levels of species aggregation. The correlation between estimated and measured values of herbage mass was significant for the majority of graminoid species at the levels of the sub‐life‐form and total plant community but not at the level of the life‐form. Interaction of habitat type and measured herbage mass, and interaction of date and measured herbage mass, were significant for a minority of species. A significant interaction of both date and habitat with measured herbage mass was found in some cases at the level of the sub‐life‐form and total plant community. Results suggest that the double‐sampling method is reliable for most graminoids and at the sub‐life‐form level, but should be applied more cautiously for forbs species, and when different sampling periods and habitat types are involved at the level of the life‐form. To avoid producing several calibration lines at the level of the species and to overcome deficiency of observations at this level, lumping morphologically similar species from the same vegetation stratum in sub‐life‐form groups is recommended for adjusting estimated herbage mass.     

Model predicting dynamics of biomass, structure and digestibility of herbage in managed permanent pastures. 2. Model evaluation

A mechanistic model, simulating the dynamics of production, structure and digestibility of managed permanent pastures, was developed. Its evaluation consisted of (i) studying model response to a range of grassland communities, cutting frequencies and site characteristics, and (ii) testing the model against experimental data, focusing on biomass accumulation and digestibility during three different cutting cycles, herbage production under a frequent cutting regime, and sward dynamics during the winter. The model realistically predicted the dynamics of biomass, structure and digestibility of herbage for various communities of permanent pastures, in different sites and under different management conditions for upland areas of the Auvergne region in France. The predicted responses to environmental conditions and cutting regimes were close to field observations and experimental results. Although the model successfully predicted the dynamics of average herbage production, it lacked precision in predicting the low biomass production observed in relation to the weather conditions found in a few specific years. The model was able to predict the dynamics of the sward during winter and is, therefore, fit for producing multiple‐year simulations. To improve the prediction of variability of biomass production and to predict the medium‐ to long‐term dynamics of permanent pastures, the model could be refined by adding seasonal and multiple‐year variation in nitrogen availability and in the proportion of grass functional groups in the grassland community.