Search

Aim: Local seed mixtures are frequently used to restore species-rich grasslands. However, it has hardly been tested whether local seed mixtures can actually be applied successfully in grassland restoration practice at larger scales and long-term. To close this gap, we report the results of a large-scale restoration study in which grasslands were restored about 15 years ago using different local seed mixtures. Location: Bavaria, SE Germany. Methods: To evaluate the efficacy of the local seed mixtures, we compared the species composition of seed mixtures and current vegetation. We then tested whether restoration success depends on site characteristics such as the size and shape (rectangle or stripe) of the grassland, restoration procedures such as topsoil removal, seed density and land use, or species habitat preferences for light, water and nutrients, and species life span (annual, perennial). Results: On average, the current vegetation contained 62.4% of all species that were present in the local seed mixtures. Species from the local seed mixtures made up on average 69.1% of the total cover in the established vegetation, whereby the species composition of the local seed mixture and vegetation differed significantly from each other. The probability that a sown species would establish increased with seed density up to 300 seeds/m². Furthermore, habitat preferences significantly affected species establishment chances, with species requiring full illumination, dry and nutrient-poor soil being more successful during restoration, reflecting the high proportion of sites with topsoil removal prior to seeding in our study. Annual species had significantly lower establishment chances compared with their perennial counterparts. Conclusions: Our study provides another piece of evidence that local seed mixtures can be applied successfully in large-scale grassland restoration projects. We provide several practical recommendations of how such practices can be further improved by using specific seed densities and creating new local seed mixtures using species that are ecologically more suitable to the restored sites. [ABSTRACT FROM AUTHOR]

Climate change has the potential to alter plant reproductive success directly and indirectly through disruptions in animal pollination. Climate models project altered seasonal precipitation patterns, and thus, the effects of climate change on available resources and pollination services will depend on the season. Plants have evolved reproductive strategies to so they are not limited by either pollen or water availability in their reproductive success, and therefore, we expect that the disruption of climate change might cause plants to be more pollen limited in seasons that become wetter than they were historically. In this study, we conducted a pollen supplementation experiment within the Global Change Experiment Facility (GCEF) in Central Germany. The GCEF experimentally manipulates future climate based on a realistic scenario of climate change for the region (drier summers and wetter springs and falls) in a native grassland ecosystem. We quantified seed production of two perennial species Dianthus carthusianorum and Scabiosa ochroleuca in response to pollination treatments (control, supplement), climate treatments (ambient and future) and season (summer and fall). Dianthus carthusianorum produced more seeds in future climate conditions independent of the season, but only when given supplemental pollen. Both species showed an increased reproduction in summer compared with the fall. We did not find evidence for our specific expectation of higher pollen limitation in the future climate and fall season (i.e., no three‐way interaction pollination × season × climate), which might be explained by the high‐drought tolerance and generalized pollination of our focal plant species. We conclude that plant reproductive success has the potential to change with changing climates and that this change will depend on how pollinator services change in the future. We offer many suggestions for future studies that are necessary to understand the context dependence and underlying mechanisms of plant reproductive responses to climate. [ABSTRACT FROM AUTHOR]

Restoration of species‐rich grasslands is a key issue of conservation. The transfer of seed‐containing local plant material is a proven technique to restore species‐rich grassland, since it potentially allows to establish genetically variable and locally adapted populations. In our study, we tested how the transfer of local plant material affected the species diversity and composition of restored grasslands and the genetic variation of the typical grassland plant species Knautia arvensis and Plantago lanceolata. For our study, we selected fifteen study sites in southeastern Germany. We analyzed species diversity and composition and used molecular markers to investigate genetic variation within and among populations of the study species from grasslands that served as source sites for restoration and grasslands, which were restored by transfer of green hay and threshed local plant material. The results revealed no significant differences in species diversity and composition between grasslands at source and restoration sites. Levels of genetic variation within populations of the study species Knautia arvensis and Plantago lanceolata were comparable at source and restoration sites and genetic variation among populations at source and their corresponding restoration sites were only marginal different. Our study suggests that the transfer of local plant material is a restoration approach highly suited to preserve the composition of species‐rich grasslands and the natural genetic pattern of typical grassland plant species. [ABSTRACT FROM AUTHOR]

Aims: This study aimed to investigate how efficiently assimilated carbon (C) is incorporated in plant biomass at an intensively managed old permanent grassland, how C is partitioned between shoots and roots and what are the implications for C sequestration. Methods: Using the eddy covariance technique, the atmosphere-biosphere exchange of CO2 was measured for two years at a sandy grassland site in northern Germany. In addition to aboveground net primary production (ANPP), belowground NPP (BNPP) was observed using the ingrowth core method. Results: The grassland showed a high productivity in terms of biomass yield (14.8 Mg dry matter ha−1 yr−1) and net CO2 uptake (−2.82 Mg CO2-C ha−1 yr−1). Photosynthetically assimilated C was converted to biomass with a high carbon use efficiency (CUE) of 71% during the growing season. However, a comparably low fraction of 17% of NPP was allocated to roots (fBNPP). Consequently, the main fraction of NPP was removed during harvest, turning the site into a net source of 0.29 Mg C ha−1 yr−1. Conclusions: Our study showed the flexibility of grass root growth patterns in response to alterations in resource availability. We conclude that highly fertilized grasslands can lose their ability for C sequestration due to low belowground C allocation. [ABSTRACT FROM AUTHOR]

Drainage and afforestation of peatlands cause extensive habitat degradation and species losses. Restoration supports peatland biodiversity by creating suitable habitat conditions, including stable high water tables. However, colonization by characteristic species can take decades or even fail. Peatland recovery is often monitored shortly after restoration, but initial trends may not continue, and results might differ among taxonomic groups. This study analyzes trends in plant, dragonfly, and butterfly diversity within 18 years after rewetting of montane peatlands in central Germany. We compared diversity and species composition of 19 restored sites with three drained peatlands and one near‐natural reference site. Restoration resulted in improved habitat conditions and benefited species diversity, but there were marked differences among taxonomic groups. Dragonflies rapidly colonized small water bodies but their diversity did not further increase in older restoration sites. Characteristic peatland vegetation recovered slowly, since it depended on a high water holding capacity that was only reached after peat started accumulating. Generally, plant diversity developed toward reference conditions albeit incompletely, even 18 years after restoration. Butterflies responded less to peatland restoration; generalists increased only temporarily and specialists could not establish. In conclusion, peatland restoration improves habitat conditions and biodiversity, while trajectories of recovery are nonlinear and incomplete after two decades. This highlights the need for long‐term monitoring and a strategic selection of indicator species for evaluation of restoration success. [ABSTRACT FROM AUTHOR]

The restoration of grasslands is one of the primary targets of nature conservation. An easy tool to stimulate the growth of plant species currently absent from the aboveground vegetation but hidden in the “dark”, is to make use of the soil seed bank. Here, seeds of rare and endangered species may still be present. However, the potential contribution of soil seed banks to effective grasslands restoration still remains unclear, as some but not many valuable species built up a persistent seed bank. To evaluate the potential of the soil seed bank for grassland restoration, we installed an experiment in 73 differently managed grasslands in Germany, where the seed bank was activated by mechanical sward disturbance. We also determined the species richness, the density of viable seeds, and the functional composition of seed banks and monitored the regeneration of the aboveground vegetation over two seasons. Our results show that sward disturbance led to an activation of the soil seed banks, which, however, contributed only little to the revegetation after sward disturbance. In addition, the severe impoverishment of the soil seed bank indicated a restricted potential for the restoration of temperate grasslands. Nevertheless, the activation of the soil seed bank increased not only the richness of arable weeds but also slightly the richness of typical grassland species. We conclude that only in recently improved and strongly species‐impoverished grasslands, sward disturbance alone might be able to slightly increase plant species richness. To achieve a distinct increase in species richness, additional diaspore transfer is needed. [ABSTRACT FROM AUTHOR]

Abstract: Grassland restoration on arable land is the second most implemented compensation measure in Germany to counteract impacts of infrastructural projects on nature. Most grassland restoration has been carried out using standardized commercial seed mixtures with large amounts of perennial generalists, cultivars and seeds of non-local origin. To evaluate whether this current practice is appropriate for developing regional types of species-rich mesophile grasslands, we analyzed four widely used treatments in a real-world setting (48 plots): (1) sowing a non-site-specific herb-poor mixture; (2) sowing a non-site-specific herb-enriched mixture; (3) sowing a site-specific herb-enriched mixture; and (4) spontaneous regeneration. After up to nine years, restored sites differed from target grasslands in: (1) number of species; (2) abundance and dominance of target species; and (3) dominance structure. Sown fields were dominated by sown species from the beginning. Because most differences were due to increasing cover of a small number of sown species, we found little development toward regional types of species-rich mesophile grasslands. In contrast, species composition on spontaneously regenerated sites changed to a greater degree and showed gradual development toward target grasslands. The limiting factor for successful restoration on all sites was availability of propagules. On sown sites, dominance patterns – particularly of Festuca rubra cultivars – had a negative effect on immigration and development of target species. For future restoration practice, we strongly recommend avoiding standardized commercial non-local seed mixtures. In particular, highly competitive cultivars should never be used. Even spontaneous regeneration should be preferred over standardized mixtures. However, in species-poor environments enrichment with selected species is necessary to reach target state. [Copyright &y& Elsevier]

Abstract: We analysed the long-term development of limestone grasslands in West- and Central Europe (Mesobromion: Gentiano-Koelerietum) under conditions of restoration comparing vegetation changes with the composition of its corresponding soil seed bank over a time period from 1992 to 2005. Because of optimal climatic, edaphic and geomorphologic conditions restoration of vegetation developed gradually into the optimal phase of the typical limestone grassland vegetation type. However, the development of the soil seed bank compared to that of the actual vegetation cover is much slower, and even after 13 years all three study plots did not reach the optimal phase compared to soil seed bank composition from well-developed control vegetation nearby. This finding agrees with the assumption that after changes of management limestone grasslands need decades or even centuries to develop into self-sustaining species-rich habitats. We also monitored the orchid Ophrys insectifera as target species and characteristic species of this type of plant association over the last 27 years. Here, population density increased continuously over time indicating that vegetation restoration efforts of the last decades have had a positive effect. We further documented that the data obtained for the soil seed bank largely depend on the applied method used for the characterization of the soil seed bank. The seedling emergence and the rinsing method provided different results, and in case of our study area the rinsing method was mostly superior. The rinsing method detected up to 20fold higher total seed numbers. [ABSTRACT FROM AUTHOR]

1. Classical ecological theory predicts a succession towards plant communities that are determined by environmental conditions. However, in ecological restoration, species composition often remains different from the predicted target community, compromising the success of restoration measures. 2. We analysed the relative importance of environmental conditions, management and distance to source populations for floodplain grassland succession following re-conversion from intensive to traditional use. The study was established at 33 grassland sites in central German river valleys. Species composition, environmental variables, past and current management, and the distance to source populations of characteristic species of traditional management (indicator species) were recorded and compared using multivariate statistics. We further tested the speed of colonization by two indicator species, Silaum silaus and Serratula tinctoria, along transects from source populations into unoccupied fields. 4. The species composition of the successional grassland was mainly determined by elevation, total soil nitrogen, distance to remnant species-rich grasslands and frequency of mowing or grazing. Elevation and distance were negatively, and frequency was positively related to the occurrence of late successional species. 5. Colonization by indicator species was only dependent on the distance to source populations; other explanatory variables were not significant. Migration from adjacent source sites of S. silaus and S. tinctoria into re-converted grasslands was slow, reaching only 40 m and 15 m after 15 years. 6. Synthesis and applications. The results demonstrated the limitations of the deterministic view on plant succession and the high relative importance of propagule availability in grassland restoration. Natural colonization will only be successful if source populations of the target species are adjacent to the restoration sites. Artificial introduction techniques are recommended to overcome dispersal barriers. [ABSTRACT FROM AUTHOR]

In 1993, experiments on the restoration of calcareous grasslands on ex-arable fields were started in order to provide new habitats for species of a small nature reserve with ancient grasslands north of Munich (Germany). The effects of diaspore transfer by the application of seed-containing hay on vegetation establishment were studied on restoration fields with and without topsoil removal for 5 years. The aim of the study was to assess plant diversity for the evaluation of restoration success by different methods including determination of species with viable seeds in the hay by germination tests, phenological investigations on hay-transfer source sites at the time of harvest, and vegetation analyses on the restoration sites. Total seed content of the hay and the number and composition of plant species with viable seeds were affected by the time of harvesting and differed between a site which had been used as arable field until 1959 and ancient grassland sites. Nevertheless, the number of established hay-transfer species showed only few differences between restoration fields. The proportion of species transferred to restoration fields in relation to the number of species with viable seeds in the hay was between 69 and 89%. Five years after the hay transfer, the proportion of the established species was still between 58 and 76%. Up to now, topsoil removal had no significant effect on the number of established hay-transfer species. After triple hay application the absolute number of transferred grassland species was higher than on sites with single hay application, but restoration efficiency was lower because many of the species with viable seeds in the hay did not establish. In general, our results showed that the transfer of autochthonous hay is a successful method to overcome dispersal limitation in restoration projects. [ABSTRACT FROM AUTHOR]

Despite great efforts in European nature conservation, semi-natural habitats such as calcareous grasslands are still suffering considerable declines due to abandonment. Shrub cutting and subsequent grazing or mowing are effective restoration measures to counteract the adverse effects of management cessation. Here, for the first time, we used leafhoppers (Auchenorrhyncha) as bioindicators to assess the conservation value of restored calcareous grasslands. We compared environmental conditions and leafhopper assemblages of 21 restored grasslands and 21 regularly managed sites (control) within the largest area of calcareous grasslands in the northern part of Germany. Furthermore, we applied Generalised Linear Mixed-effects Models (GLMM) to assess the effects of environmental parameters on species richness of leafhoppers within the restored grasslands. After a period of three to eight years, the restoration measures had led to species-rich leafhopper assemblages, including both habitat specialists and threatened species. However, we still found clear differences in leafhopper composition compared to the control. Within the restored grasslands, a pronounced field layer and an increased number of host plants positively affected species richness. In conclusion, the restored grasslands form open fringe-like habitat structures that clearly enhance the conservation value of calcareous grasslands by (i) harbouring numerous exclusive (indicator) species leading to a higher leafhopper diversity at the habitat level and (ii) by providing habitats for several habitat specialists which occurred only rarely on control grasslands. In order to maintain or even increase the biodiversity of calcareous grasslands, we recommend a combination of traditional grazing and small-scale shrub cutting. • First study using leafhoppers for the evaluation of calcareous grassland restoration • Restoration measures have formed open fringe-like habitat structures within calcareous grasslands. • These new habitat structures were colonized by species-rich leafhopper assemblages. • Species composition clearly differed between restored and extant calcareous grasslands. • Restored sites provided habitats for several specialised species. [ABSTRACT FROM AUTHOR]

Land-use change has been identified as the most important factor responsible for the recent loss of biodiversity. One major problem is the abandonment of management, especially in semi-natural grassland ecosystems. Numerous restoration projects were, therefore, launched to counteract this development. However, the effects of restoration are not yet fully understood. Especially the early successional stage, i.e. the composition of the vegetation in the first years after the restoration measures, has received little attention probably due to its supposedly low conservation value. As study area, we selected the largest area of calcareous grasslands at the northern edge of the German uplands. About 35 ha of formerly abandoned calcareous grasslands have been restored by cutting shrubs here in the last eight years. Within the restored sites, 50 randomly chosen vegetation surveys were made and the results were compared to 50 control plots. Our study revealed that the value of the early successional stage for biodiversity conservation was previously underestimated. Even though the target state – calcareous grassland – is far from being reached, the early successional stage enhances the conservation value of calcareous grasslands by (i) increasing diversity at the landscape scale, (ii) hosting numerous target species as well as (iii) contributing to a higher habitat quality and heterogeneity. Future restoration of calcareous grasslands should focus on sites with low nutrient content of the soil, a shallow topsoil, and a warm microclimate. At such sites, the chances are greatest that species with a high nature conservation value, i.e. characteristic species of calcareous grasslands as well as thermophilous fringe and ruderal species, will re-establish. • Large-scale restoration study within one of the largest calcareous grassland areas of central Germany • The restored sites in their early successional stage increased phytodiversity. • They were characterised by a mixture of plants from many different ecological groups. • Number of thermophilous fringe and ruderal species was highest within the restored sites. • Restored sites harboured a high number of functional plants such as pollen sources for specialised wild bees. [ABSTRACT FROM AUTHOR]

Sphagnum farming is paludiculture on rewetted bogs. It allows to use abandoned cut-over bogs and degraded bog grasslands with benefits for climate change mitigation, nutrient retention, and biodiversity. Sphagnum farming aims to cultivate Sphagnum biomass for harvest as an agricultural crop, e.g. to provide raw material for growing media. This new type of peatland agriculture includes the selection of highly productive species and active management to maximise yields.A production system with Sphagnum production fields, irrigation system and causeways is successfully tested on ca. 14 ha pilot study site in NW Germany on former bog grassland. To convert the bog grassland into a Sphagnum farming site firstly the sod was removed and used for constructing bunds used as causeways, before Sphagnum fragments were spread on the bare even peat surface to ensure optimal water levels over the entire Sphagnum production field after rewetting. Commercial Sphagnum farming involves regular on-site controls, precise water management, weed management of production fields, cleaning of irrigation ditches and mowing of causeways.For the fast establishment and optimal growth of a dense Sphagnum lawn water tables just below Sphagnum surface has to be secured permanently by regular adjustment of water table, irrigation of the Sphagnum production fields, and cleaning of the irrigation system. At our study site there is a water surplus in winter, whereas in spring and summer evapotranspiration exceeded precipitation, creating a water deficit which is compensated by a mean annual irrigation amount of 160 mm (i.e. 1,600 m³ ha-1 yr-1), differing between the years up to 360 mm. Next to the cultivated Sphagnum also vascular plants are establishing and may retard Sphagnum growth by shading, litterfall, and competition for water and nutrients. Thus, the vascular plant cover on Sphagnum production fields should be managed to be low. Regular mowing every three weeks during the vegetation period retained vascular plant cover below 30 %.With the management at our Sphagnum farming study site Sphagnum produced dry masses up to 9 t ha-1 yr-1. However, since Sphagnum farming is still in its infancy more research is necessary to reach technological maturity and to reduce costs for large-scale implementation. [ABSTRACT FROM AUTHOR]

The article presents abstracts on grassland restoration topics such as "Grassland Restoration in Practice: Do We Achieve the Targets? A Case Study from Saxony-Anhalt/ Germany," by S. Tischew and M. K. Conrad and "Demographic Processes Limiting Seedling Recruitment in Arid Grassland Restoration," by J. James.

The article outlines the study conducted by Detlev Kelm of the Leibniz Institute for Zoo and Wildlife Research on the vital role of bats of the tropical forests in Germany. Researchers found that bats can help reforest the tropics because their droppings help spread seeds beyond the forest edge. They installed simple towers made of sawdust and concrete near a Costa Rica nature reserve, which is ravaged by agriculture and logging, because they wanted to lure bats out of their normal forest habitat and into the disturbed regions, with no large, hollow tree trunks in which they can hang out during the day. With it, they were able to gather 10 species of bats, thus significantly increasing the number and types of seeds in the neighborhood.