Tuexenia : Mitteilungen der Floristisch-Soziologischen Arbeitsgemeinschaft, Band 36 (2016)
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- phytosociology (3)
- species richness (3)
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- Allio-Stipetum (1)
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Halting the loss of grassland biodiversity and restoring degraded ecosystems are high priority tasks in the EU Biodiversity Strategy. Sowing low-diversity seed mixtures is widely used in grassland restoration because of its high predictability and fast, promising results. Generally, the sown perennial grasses establish within a few years and form a dense sward, which effectively suppresses weeds. Unfortunately, these grasslands are often species-poor because the sown grasses hamper the colonisation of target grassland forbs. Our aim was to test a novel approach to increase the diversity of species-poor grasslands. We selected eight 8-year-old grasslands restored by low-diversity seed sowing where we created 32 establishment gaps by breaking up the grass sward and sowing a high-diversity seed mixture (35 native species). Altogether, we established three grazed gaps (1m × 1m, 2m × 2m and 4m × 4m) and one fenced gap (4m × 4m) per site and monitored the presence and abundance of sown and non-sown species within a time frame of two years. We asked the following questions: (1) Which target species establish most successfully? (2) What is the effect of establishment gap size on the establishment success of target species and weeds? (3) What is the effect of management (grazed versus not managed) on the species composition of the establishment gaps? Our results showed that by creating establishment gaps and sowing diverse seed mixtures, we were able to overcome microsite and propagule limitation, successfully introducing target species into the species-poor grasslands. We found that all sown species established in the gaps, and the majority of the species maintained or even increased their first-year cover in the second year. Smaller gaps were characterised by lower cover of sown species and a quite stochastic development compared to the larger ones. Weed cover was moderate in the first year and decreased significantly in the second year, regardless of gap size. Therefore, in restoration practice, the use of larger establishment gaps is recommended. We found that the cover of sown species and weeds were similar in the grazed and unmanaged gaps during our study. However, management by extensive grazing might be crucial in the long-term because livestock can disperse target species propagules and create microsites. Our study shows that establishment gaps can serve as biodiversity hotspots. Further studies need to clarify to what extent they can improve the restoration success across the entire grassland.
Plant diversity change for cities and their surroundings is well documented. For rural areas such studies are difficult as literature data are mostly insufficient. We reconstructed phytodiversity change in the Feldatal community (Germany, Hesse) by comparison of historical herbarium collections (1945–1976, Hans Hupke) with a recent floristic survey (2012). The study area is a rural area typical for Central Europe, dominated by agriculture and forestry and with a stable human population. Floristic diversity decreased (683 to 497 species; 31% of the total flora), principally by disappearance of species of unimproved grassland, fields and villages. The small number of newly documented species (33 spp.; 5% of total flora) comprises mostly naturalized ornamentals and salt tolerant species along roads. Plant diversity change of the last decades in rural landscapes in Central Europe was mainly dependent on the intensification of agriculture.
Inland sand vegetation, in our case steppic sandy grassland on base-rich soils, is highly endangered in Europe and therefore in the focus of restoration ecology. While there are studies which deal with short-term restoration success, results for an extended time are rare. We were able to analyse the success of a three-step restoration measure for 10 years.
The experiment was established on an exarable field in the Upper Rhine valley, Hesse, Germany. The three-step restoration approach comprised 1) abiotic restoration by deep-sand deposition, 2) inoculation with raked/mown plant material from two different donor sites with well-developed Koelerion glaucae/Allio-Stipetum vegetation and 3) low-intensity grazing by donkeys. The vegetation of the restoration and donor sites (also serving as reference sites to assess restoration success) was sampled on six permanent plots, respectively. Data analyses included ordination, classification and target-species ratios (TSR: relation of target species to all species).
Detrended correspondence analysis revealed a continuous succession of the restoration plots towards the corresponding reference plots: open soil decreased, ruderal species declined and target species increased. While speed of succession decreased, there was still a further improvement in the tenth year. The qualitative TSR (number of target species) reached a plateau after the sixth year with values only slightly lower than at the reference sites. The quantitative TSR (cover of target species) showed a steady improvement and even excelled one reference site. Koelerion glaucae species were present with constancy 17–67% since the 3rd year, with 33–100% since the 7th year. It does not completely resemble either reference site due to a mixture of propagules of both donor sites (e.g. by wind and donkeys) and input from the surroundings. Already in the first year, three Red-list species established themselves, since the 8th year 23 Red-list/near-threatened species have been present. Some ruderal species colonised the restoration site and occurred permanently.
Additionally, we studied the establishment of the highly threatened species Bassia laniflora after inoculation for 6–12 years on three further plots adjacent to the other ones. One of these plots was located on a former sandy field without abiotic restoration; two other plots represented typical Koelerion glaucae vegetation on a newer deep-sand deposition. Bassia laniflora established itself well on all plots. We conclude that restoration of steppic sandy grassland, including highly threatened species, was not only permanently, but increasingly successful over a time span of 10 years. Management by grazing, however, will remain essential to suppress ruderalisation.
The majority of studies investigating plant functional traits have used species average trait values, and assumed that average values were sufficiently representative of each species considered. Although this approach has proven valuable in community ecology studies, plant functional traits can significant-ly vary at different scales, i.e. between but also within populations. The study of species functional trait variability can facilitate increasingly accurate studies in community ecology. Nevertheless, the current extent of within-site plant trait variability has been poorly addressed in the literature. Calcareous grass-lands are ecosystems well-suited to study plant trait variation at small spatial scales. Many species are present on heterogeneous calcareous sites, with significant differences in hydric status due to variations in soil depth, soil moisture, aspect, and slope. This study assesses the extent of intra-population func-tional trait variability and tests the hypothesis that this variability can be explained by within-site envi-ronmental heterogeneity. Three functional traits (SLA-specific leaf area, LDMC-leaf dry matter con-tent, and plant vegetative height) were assessed in three populations of four calcareous grassland spe-cies totalling 950 individuals. The heterogeneity in soil depth and potential direct incident radiation was also quantified and related to plant functional trait variability. The intra-population functional trait variability was compared to the inter-population variability of collected data and global inter-population variability data obtained from the worldwide TRY functional traits database. The results showed that SLA, LDMC, and plant height are characterized by considerable intra-population variation (SLA: 72–95%, LDMC: 78–100% and vegetative height: 70–94% of trait variability). The results also indicate higher plant height and larger SLA for individuals located in plots with deeper soils or lower potential direct incident radiation, on gentle slopes or north-facing slopes. Our findings additionally support the concept that higher plant height, higher SLA, and lower LDMC are related to higher availability of soil water. Individuals on shallow soils or in more exposed areas are better equipped to cope with environ-mental stress. Our results indicate plasticity or local adaptation in individuals to environmental hetero-geneity. This study suggests that detailed analyses involving plant functional traits require measure-ments in situ from a large number of individuals, as the degree of individual response strongly depends on an individual’s location and its micro-environmental conditions. Neglecting intra-population trait variability may be critical, as intraspecific variation can be very high at the population scale, and is likely to be driven by local environmental heterogeneity.
Dry open rocky grassland vegetation on shallow ultramafic soils in the Central Balkans represents typical secondary grasslands, which have developed mainly in the zone of thermophilous mixed deciduous broadleaved and pine forests. Although all relevant national and regional syntaxonomic reviews classify these rocky grasslands within the distinct order Halacsyetalia sendtneri, the syntaxonomic position of the order in different systems of classification has varied in the past. Considering this as well as the fact that there have been no synoptic works on this specific vegetation type, we gathered all available data on the order Halacsyetalia sendtnerii from the serpentinites of the Western and Central Balkan Peninsula for its critical evaluation. The results obtained in our analyses allowed us to propose a new syntaxonomic concept, which is partly in accordance with previously published syntaxonomic schemes. Two alliances can be distinguished: Centaureo kosaninii-Bromion fibrosi and Potentillion visianii, for which the diagnoses, diagnostic and constant taxa are given. Furthermore, we discussed the syntaxonomic position of the order Halacsyetalia sendtneri with respect to the classes Festuco-Brometea and Koelerio-Corynephoretea, as within the analysed associations, many taxa diagnostic for the class Koelerio-Corynephoretea were registered. The thermophytic pioneer grasslands and therophyte sward communities included in the alliance Thymion jankae nomen. inval., characterised by the absence of typical species of the order Halascyetalia sendtneri and presence of taxa diagnostic for the class Koelerio-Corynephoretea, are temporarily left within the order Halacsyetalia sendtneri. Finally, we provided nomenclatural adjustments for the analysed associations when necessary, although a conclusive judgement regarding all the associations currently included within the analysed order can only be made after more detailed field surveys including data on cryptogams as well as joint analyses including all floristically and ecologically similar syntaxa (e.g. Astragalo-Potentilletalia, Festucetalia valesiacae).
This paper compares the floodplain forests from Romania to those described from Central and Southeastern Europe from syntaxonomical and ecological perspectives and proposes a clear and ade-quate vegetation classification system that was needed for the Romanian floodplain forests. We performed a syntaxonomical analysis and classification of 473 vegetation relevés published from all nine Romanian provinces, between the years 1968 and 2015. The plant communities, established on the basis of character and differential species, were grouped within the alliance Alnion incanae Pawłowski 1928, according to current phytosociological consensus. The floristic structure of each syntaxon is presented in a synoptic table with species constancy expressed as a percentage. Since plant communi-ties specific to intramontane river floodplains are notably different from those in the plains, we grouped the associations within two different suballiances. Within the suballiance Alnenion glutinosae-incanae Oberdorfer 1953, we included the associations Stellario nemorum-Alnetum glutionosae Lohmeyer 1957, Telekio speciosae-Alnetum incanae Coldea 1990, and Carici remotae-Fraxinetum excelsioris Koch ex Faber 1936. In the suballiance Ulmenion Oberdorfer 1953, we included the associations Fraxino pannonicae-Ulmetum glabrae Aszód 1935 corr. Soó 1963, Ulmo campestris-Fraxinetum holotrichae Borza ex Sanda 1970 and Fraxino pallisae-Quercetum pedunculiflorae Oprea 1997. In order to show the distribution of these associations within the territory of Romania, we have generated two maps displaying the provenance of the analyzed relevés. The proposed classification system will facilitate the phytosociological and ecological investigation of floodplain forests and support the activities aiming at their conservation.
Semi-dry grasslands were once widely distributed communities, but today they represent some of the most vulnerable habitats in Central Europe. European and national legislation and non-governmental organizations have managed to protect some of the remaining fragments. However, despite their status as Natura 2000 habitats, they are often endangered due to improper management, fragmentation and edge effects from adjacent croplands. By using a sample of 44 semi-dry hay meadows in the south-eastern Alpine Foreland of Styria, we investigated how species-richness and trait composition of semi-dry grassland species respond to variation in patch size, connectivity, abiotic site factors and management regimes. We used linear regression models to identify the most important drivers for richness of typical semi-dry grassland species and thus conservation value. The number of typical semi-dry grassland species was highest in well-connected fragments, i.e. units that shared two or more borders with neighbouring species-rich grasslands. Furthermore, large semi-dry grasslands (> 8000 m²) had highest numbers of semi-dry grassland species and highest relevance for conservation; no difference was found among smaller fragment sizes. Unregular management was associated with increased presence of competitive species which replaced stress-tolerant specialists. Our study indicates that under eutrophication, small fragment size and isolation, only large semi-dry grasslands can sustain a high number of species with high conservation value. The conservation value of smaller semi-dry grassland fragments could be improved by buffer zones, adapted mowing treatments and periodical sheep grazing.
In Italy most of the habitats hosting terricolous lichens are found in the Alps and along the coasts, but some lichen-rich plant communities are also present in the Po Plain. We report a study of terrico-lous lichen communities found in dry grasslands attributed to Spergulo vernalis-Corynephoretum canescentis in the western Po Plain (Northern Italy), in accordance with the Braun-Blanquet approach. Relevés (138) were carried out in several developmental stages of the Corynephorus grassland. They were sorted manually and analyzed using ANOSIM, non-parametric MANOVA and PCA. Indicator species of the groups were found by means of INDVAL and SIMPER analyses and literature. Seven lichen vegetation types were distinguished. These were attributable to 4 described associations: Stere-ocauletum condensati, Cladonietum foliaceae (in which we found 3 subassociations: typicum, cladonietosum furcatae and cladonietosum subrangiformis), Cladonietum mitis and Cladonietum rei, and to one impoverished community (Cetraria aculeata community). Ordination of floristic variables showed several overlaps between communities, underlining the depleted floristic conditions found in the study area, where several species occur in many communities and other species are very rare, and thus play a minor role in the differentiation of the lichen vegetation types. Overlaps are also referable to intermediate conditions between one community and another, reflecting dynamic relationships, with Stereocauletum condensati, Cetraria aculeata community and Cladonietum foliaceae typicum having the most distinct pioneer character and Cladonietum mitis being the most evolved. Ordination of eco-logical variables based on the indices of substrate pH, light and humidity requirements and tolerance to eutrophication showed several overlaps between the communities, found to be from acidophytic to subneutrophytic, from rather to very photophytic, from mesophytic to rather xerophytic and from anitrophytic to slightly nitrophytic. Rarity in Italy and conservation needs are discussed in detail, also in comparison with the situation of the same communities in central European Corynephorus grasslands. These grasslands and their typical lichen communities are rare in Italy and, though somewhat depleted, they are the habitat of several threatened lichen species at the southern margin of their distribution range. Therefore management plans should always consider both the cryptogamic and the vascular plant communities.
This paper is the continuation of a survey of the scree vegetation in alpine landscapes of western Pamir-Alai Mts in Tajikistan. In total, 105 phytosociological relevés were collected in the colline and montane belt in 2012‒2014, applying the Braun-Blanquet method. Phytocoenoses inhabiting mobile or fairly stabilised screes of different sizes of rock particles in the montane and colline zone are herein described. A hierarchical syntaxonomic synopsis of scree communities in the western Pamir Alai Mts is provided. The collected vegetation samples represent the majority of the variations among the phytocoenoses of gravel, pebble, cobble and rock block slides and screes. As a result of field survey and numerical analyses, eight associations ‒ Cousinietum corymbosae, Eremostachyetum tadschikistanicae, Cousinietum refractae, Caccinietum dubiae, Eremuretum sogdiani (with two subassociations: E. s. typicum and E. s. delphinietosum decolorati), Feruletum kuhistanicae, Zygophylletum atriplicoidis and Corydalidetum kashgaricae ‒ have been described. Because of their floristic composition, all of these communities have been assigned to a new alliance Alceion nudiflorae within the Sileno brahuicae-Scutellarietalia intermediae order and Artemisio santolinifoliae-Berberidetea sibiricae class. The main factors determining the species composition of the classified associations seem to be scree mobility, rock particle size, elevation above sea level and slope inclination. Saxicolous vegetation in Tajikistan reveal an extraordinary diversity and richness in terms of species composition and beta diversity along the main environmental gradients in this mountaionous areas. A further geobotanical survey is needed, especially in eastern Pamir and adjacent areas to fully recognize the chasmophytic plant communities of this rocky land.
Elevational gradients in high mountain ranges are particularly suitable to study and understand patterns and drivers of plant community diversity and composition, yet there are only few studies that explicitly addressed this topic for the European Alps. Here we analysed an elevational gradient in grasslands of the Gran Paradiso National Park (NW Italy) from c. 1,700 to 3,100 m a.s.l. We recorded vascular plant species composition in 13 100-m² plots, each with two series of nested subplots from 0.0001 to 10 m², as well as a set of environmental parameters (topography, soil). Beta-diversity was assessed via the z-values of power-law species-area relationships, both across all plot sizes and from one plot size to the next bigger one. Diversity-environment relationships were assessed with multi-model inference based on Akaike information criterion (AIC), while scale dependence in z-values across plot sizes was analysed with an ANOVA. Life forms and three major functional traits (specific leaf area = SLA, canopy height, seed mass) were derived from trait databases to calculate fractions of life forms and community-weighted means for the metric traits. Species richness on 100 m² ranged from 17 to 65, with a mean of 43.5. The z-values were within a typical range known for European grasslands (mean: 0.227), with non-significant scale dependence. The importance of environmental factors for richness changed across grain sizes, with inclination (positive effect), mean soil depth and soil skeleton content (both: negative effect) being most influential at grain sizes of 0.0001–1 m². By contrast, soil pH was most important (with a unimodal relationship) for 10 and 100 m². After account-ing for the other environmental factors, elevation showed a moderate unimodal relationship only for the two largest grain sizes. By contrast, functional composition showed strong and mostly significant rela-tionships with elevation: hemicryptophytes and geophytes became rarer and chamaephytes more fre-quent, while community-weighted means of SLA, canopy height and seed mass decreased. Our findings highlight the scale dependence of biodiversity patterns, thus pointing to the need of multi-scale sampling to reach comprehensive understanding. Further, we could provide one of the first documentations of biodiversity and functional composition along an elevational gradient in the Alps, some in agreement with expectations, others not. This suggests that more extensive studies with a similar design in this and other regions of the Alps could be a valuable contribution to the understanding of how environmental factors drive components of biodiversity as well a functional community assembly.