Restoration of plant diversity in permanent grassland by seeding: assessing the limiting factors along land‐use gradients

1. Land-use intensification has caused dramatic declines in grassland biodiversity, and in Europe this decline has not yet been halted. Therefore, a major challenge in ecological restoration is to effectively restore plant diversity in permanent grasslands, that is, long-term managed grassland not being used as cropland. As species richness is often limited by seed dispersal, introducing locally absent species is crucial. Seeding diverse seed mixtures is an appropriate tool, but restoration outcomes are highly variable. Considering constraints by land-use intensity and plant functional traits during restoration could improve the efficacy of restoration efforts. 2. We established a full-factorial experiment with high-diversity seeding and topsoil disturbance in 73 grasslands along land-use intensity and productivity gradients and evaluated the restoration success over 5 years. In addition, after 5 years we assessed the number of established species and tested whether specific traits promoted the establishment of sown species in interaction with productivity. 3. Plant diversity increased considerably when seeding and disturbance were combined while seeding alone only slightly increased species richness. Along land-use gradients, we found no direct effects of grazing or mowing on the establishment of sown species, but fertilization indirectly limited establishment in the combined treatment via a negative effect of productivity. 4. Functional traits structured the establishment of sown species, especially in the combined treatments, but effects varied with productivity. Species with low seed mass and low specific leaf area had greater establishment success in low-productivity grasslands, whereas species with high seed mass had greater establishment in high-productivity grasslands. 5. Synthesis and applications. Our results highlight the potential of using diverse seed mixtures for biodiversity restoration in a wide range of permanent grasslands, especially when combined with topsoil disturbance. However, productivity both limited restoration success and affected establishment via an interaction with plant functional traits. As productivity is a major constraint in grassland restoration, we strongly recommend to first stop fertilization and reduce soil nutrient loads in highly productive grasslands. Restoration by seeding, with or without disturbance, should only be applied when productivity is reduced and the local environment should be considered to compile site-specific seed mixtures to maximize restoration success.ISSN:0021-8901ISSN:1365-266

Integrative Begabtenförderung: Ein Beitrag zur Schul- und Unterrichtsentwicklung an Sachsens Grundschulen

Nach einer einjährigen Vorbereitungszeit wurde mit dem Beginn des Schuljahres 2002/03 an der 16. Grundschule »Josephine« Dresden der Schulversuch Grundschule mit erweitertem Angebot für Schüler mit besonderer Begabung« eingerichtet, um besonders begabte Grundschüler wirksam zu fördern und darüber hinaus durch Impulse zur Implementierung der Begabtenförderung in die Unterrichtspraxis die Qualität des Unterrichtes in allen Grundschulen des Freistaates Sachsen weiter zu entwickeln. Außerdem wurde mit dem Schulversuch eine Lücke zwischen begabungs-orientierten Kindertageseinrichtungen in Dresden und dem Sächsischen Landesgymnasium St. Afra Meißen geschlossen und damit ein altersübergreifendes Angebot für besonders begabte Kinder bzw. Schüler geschaffen. In der vorliegenden Dokumentation bereiten Lehrerinnen, Erzieherinnen und Eltern der 16. Grundschule »Josephine« sowie der wissenschaftliche Begleiter des Schulversuchs Ergebnisse als Impuls für die Schul- und Unterrichtsentwicklung auf. Redaktionsschluss: 17.11.201

Integrative Begabtenförderung: Ein Beitrag zur Schul- und Unterrichtsentwicklung an Sachsens Grundschulen

Nach einer einjährigen Vorbereitungszeit wurde mit dem Beginn des Schuljahres 2002/03 an der 16. Grundschule »Josephine« Dresden der Schulversuch Grundschule mit erweitertem Angebot für Schüler mit besonderer Begabung« eingerichtet, um besonders begabte Grundschüler wirksam zu fördern und darüber hinaus durch Impulse zur Implementierung der Begabtenförderung in die Unterrichtspraxis die Qualität des Unterrichtes in allen Grundschulen des Freistaates Sachsen weiter zu entwickeln. Außerdem wurde mit dem Schulversuch eine Lücke zwischen begabungs-orientierten Kindertageseinrichtungen in Dresden und dem Sächsischen Landesgymnasium St. Afra Meißen geschlossen und damit ein altersübergreifendes Angebot für besonders begabte Kinder bzw. Schüler geschaffen. In der vorliegenden Dokumentation bereiten Lehrerinnen, Erzieherinnen und Eltern der 16. Grundschule »Josephine« sowie der wissenschaftliche Begleiter des Schulversuchs Ergebnisse als Impuls für die Schul- und Unterrichtsentwicklung auf. Redaktionsschluss: 17.11.201

Contribution of the soil seed bank to the restoration of temperate grasslands by mechanical sward disturbance

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

And the winner is …. ! A test of simple predictors of plant species richness in agricultural grasslands

ISSN:1470-160XISSN:1872-703

And the winner is …. ! A test of simple predictors of plant species richness in agricultural grasslands

Land-use intensification, nutrient enrichment and enhanced productivity levels are major drivers of the current biodiversity loss in agricultural grasslands. Although these drivers are potentially strongly causally linked, their potential to explain changes in biodiversity can enhance each other and often varies over time. Here, we explored the explanatory power of different abiotic drivers and the Ellenberg indicator value for nutrient availability to predict plant species richness using data of 150 grassland plots over seven years. The approach also allows to assess the temporal robustness of many of these drivers. Our results revealed the Ellenberg indicator value for nutrients to be the best and temporally most consistent predictor of plant species richness. Unweighted mean Ellenberg values showed an even stronger negative relationship to plant species richness than abundance weighted mean values. Direct measurements of soil and plant biomass nutrients, aboveground biomass and land-use intensity predicted plant species richness less well and showed considerable temporal variability in the respective association. In case of biomass nitrogen and phosphorus concentrations, current year weather conditions are assumed to strongly affect the strength of the relationship by shifting the phenological development considerable among sampling years. Although mainly driven by aboveground biomass, a combination of biomass nutrient concentrations with productivity, i.e. the nutrient stock in the aboveground biomass, turned out to better predict plant species richness than its single components and inter-annual variability in the relationship was markedly lower. Especially for aboveground biomass and the intensity of land-use, long-term mean values significantly improved the explanatory power compared to single year measurements. We conclude that studies explaining biodiversity changes should carefully take into account temporal variability in the drivers under study before judging the strength of a particular mechanistic relationship

Effects of mowing, grazing and fertilization on soil seed banks in temperate grasslands in Central Europe

ISSN:0167-8809ISSN:1873-230

Effects of mowing, grazing and fertilization on soil seed banks in temperate grasslands in Central Europe

Soil seed banks support the recovery of plant species and communities after disturbances. Against the background of increasing disturbance frequencies due to current changes in climate and land use, the importance of seed banks to maintain ecosystem functioning of grasslands is likely to increase. This makes seed bank ecology a highly relevant topic of studies on ecosystem functioning. One of the main drivers of seed bank composition and density in grasslands is the current management. Although highly intensive grassland management can affect soil seed banks negatively, it is still unclear which component of management – fertilization, mowing or grazing – is the most influential. We studied soil seed banks of 73 mesic grasslands, which were arranged along a gradient of land-use intensity, by two seasonally differing surveys. Grasslands generally exhibited rather poor seed banks with low numbers of species and seedlings. Both were even lower in spring compared to autumn sampling. Grassland management turned out to affect soil seed banks in a complex way, via direct and indirect paths. While intensive mowing and fertilization decreased species richness and seedling density, grazing intensity increased species richness in the seed bank. Thus, land-use intensity, an index calculated as a sum of all three components, had highly ambivalent effects on seed banks. We conclude that the positive effect of grazing on soil seed banks makes pastures more resilient towards mechanic disturbances as compared to meadows

Microbial drivers of plant richness and productivity in a grassland restoration experiment along a gradient of land‐use intensity

Plant–soil feedbacks (PSFs) underlying grassland plant richness and productivity are typically coupled with nutrient availability; however, we lack understanding of how restoration measures to increase plant diversity might affect PSFs. We examined the roles of sward disturbance, seed addition and land-use intensity (LUI) on PSFs. We conducted a disturbance and seed addition experiment in 10 grasslands along a LUI gradient and characterized plant biomass and richness, soil microbial biomass, community composition and enzyme activities. Greater plant biomass at high LUI was related to a decrease in the fungal to bacterial ratios, indicating highly productive grasslands to be dominated by bacteria. Lower enzyme activity per microbial biomass at high plant species richness indicated a slower carbon (C) cycling. The relative abundance of fungal saprotrophs decreased, while pathogens increased with LUI and disturbance. Both fungal guilds were negatively associated with plant richness, indicating the mechanisms underlying PSFs depended on LUI. We show that LUI and disturbance affect fungal functional composition, which may feedback on plant species richness by impeding the establishment of pathogen-sensitive species. Therefore, we highlight the need to integrate LUI including its effects on PSFs when planning for practices that aim to optimize plant diversity and productivity.ISSN:0028-646XISSN:1469-813