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Long-term analyses of biodiversity data highlight a ‘biodiversity conservation paradox’: biological communities show substantial species turnover over the past century 1 , 2 , but changes in species richness are marginal 1 , 3 – 5 . Most studies, however, have focused only on the incidence of species, and have not considered changes in local abundance. Here we asked whether analysing changes in the cover of plant species could reveal previously unrecognized patterns of biodiversity change and provide insights into the underlying mechanisms. We compiled and analysed a dataset of 7,738 permanent and semi-permanent vegetation plots from Germany that were surveyed between 2 and 54 times from 1927 to 2020, in total comprising 1,794 species of vascular plants. We found that decrements in cover, averaged across all species and plots, occurred more often than increments; that the number of species that decreased in cover was higher than the number of species that increased; and that decrements were more equally distributed among losers than were gains among winners. Null model simulations confirmed that these trends do not emerge by chance, but are the consequence of species-specific negative effects of environmental changes. In the long run, these trends might result in substantial losses of species at both local and regional scales. Summarizing the changes by decade shows that the inequality in the mean change in species cover of losers and winners diverged as early as the 1960s. We conclude that changes in species cover in communities represent an important but understudied dimension of biodiversity change that should more routinely be considered in time-series analyses. Time-series data including 1,794 plant species from 7,738 vegetation plots in Germany between 1927 and 2020 reveal patterns of change in biodiversity, and suggest that more species declined than increased in abundance during this period.

Questions Has plant species richness in semi‐natural grasslands changed over recent decades? Do the temporal trends of habitat specialists differ from those of habitat generalists? Has there been a homogenization of the grassland vegetation? Location Different regions in Germany and the UK. Methods We conducted a formal meta‐analysis of re‐survey vegetation studies of semi‐natural grasslands. In total, 23 data sets were compiled, spanning up to 75 years between the surveys, including 13 data sets from wet grasslands, six from dry grasslands and four from other grassland types. Edaphic conditions were assessed using mean Ellenberg indicator values for soil moisture, nitrogen and pH. Changes in species richness and environmental variables were evaluated using response ratios. Results In most wet grasslands, total species richness declined over time, while habitat specialists almost completely vanished. The number of species losses increased with increasing time between the surveys and were associated with a strong decrease in soil moisture and higher soil nutrient contents. Wet grasslands in nature reserves showed no such changes or even opposite trends. In dry grasslands and other grassland types, total species richness did not consistently change, but the number or proportions of habitat specialists declined. There were also considerable changes in species composition, especially in wet grasslands that often have been converted into intensively managed, highly productive meadows or pastures. We did not find a general homogenization of the vegetation in any of the grassland types. Conclusions The results document the widespread deterioration of semi‐natural grasslands, especially of those types that can easily be transformed to high production grasslands. The main causes for the loss of grassland specialists are changed management in combination with increased fertilization and nitrogen deposition. Dry grasslands are most resistant to change, but also show a long‐term trend towards an increase in more mesotrophic species. Semi‐natural grasslands are famous for their high plant species diversity. In a meta‐analysis of 23 data sets from Germany and the UK we show that the total species richness in wet grasslands has declined over time, while in dry grasslands the number of species did not consistently change. However, there was a general decrease in the proportion of habitat specialists.

Semi‐natural mountain grasslands are increasingly exposed to environmental stress under climate change. However, which are the environmental factors that limit plants in these grasslands? Also, is the present management effective against these changes? Fitness‐related functional traits may offer a way to detect changes in performance and provide new insights into their vulnerability to climate change. We investigated changes in performance and variability of functional traits of the mountain grassland target species Arnica montana along a climate gradient in Central German low mountain ranges. This gradient represents at its lower end climate conditions that are expected at its upper end under future climate change. We measured vegetative, generative, and physiological traits to account for multiple ways of plant responses to the environment. Using mixed effects and multivariate models, we evaluated changes in trait values among individuals as well as the variability of their populations in order to assess performance under changing summer aridity and different management regimes. Fitness‐related performance of most traits showed strongly positive associations with reduced summer aridity at higher elevations, while only specific leaf area and leaf dry matter content showed no association. This suggests a higher performance level at less arid montane sites and that the physiological traits are less sensitive to this climate change factor. The coefficient of variation of almost all traits declined steadily with decreasing site aridity. We suggest that this reduced variability indicates a lower environmental stress level for A. montana toward its environmental optimum at montane elevations, especially because the trait performance increased simultaneously. Surprisingly, management factors and habitat characteristics had only low influence on both trait performance and variability. In summary, summer aridity had a stronger effect to shape the trait performance and variability of A. montana under increased environmental stress than management and other habitat characteristics. We illustrate that summer aridity predicts the performance and variability of fitness‐related functional traits of the threatened mountain grassland species Arnica montana under climate change conditions and highlight that increased environmental stress will considerably affect the fitness of Arnica montana, while management has only limited influence to mediate impacts.

Eutrophication through atmospheric nutrient deposition is threatening the biodiversity of semi-natural habitats characterized by low nutrient availability. Accordingly, local management measures aiming at open habitat conservation need to maintain habitat-specific nutrient conditions despite atmospheric inputs. Grazing by wild herbivores, such as red deer (Cervus elaphus), has been proposed as an alternative to mechanical or livestock-based measures for preserving open habitats. The role of red deer for nutrient dynamics in protected open habitat types, however, is yet unclear. Therefore, we collected data on vegetation productivity, forage removal, quantity of red deer dung and nutrient concentrations in vegetation and dung from permanent plots in heathlands and grasslands (eight plots à 225 m2 per habitat type) on a military training area inhabited by a large population of free-ranging red deer over one year. The annual nutrient export of nitrogen (N) and phosphorus (P) by red deer grazing was higher than the nutrient import through red deer excreta, resulting in an average net nutrient removal of 14 and 30 kg N ha−1 a−1 and 1.1 and 3.3 kg P ha−1 a−1 in heathlands and grasslands, respectively. Even when considering approximate local atmospheric deposition values, net nutrient depletion due to red deer grazing seemed very likely, notably in grasslands. Demonstrating that grazing by wild red deer can mitigate the effects of atmospheric nutrient deposition in semi-natural open habitats similarly to extensive livestock grazing, our results support the idea that red deer are suitable grazing animals for open habitat conservation.

In this study, we conducted the plant population investigations in the Goettingen forest, located in Low Saxony, Germany, from 2022 to 2023. Our research focused on six distinct populations of Stellaria holostea L. across six plots within the forest. These plots encompassed varying tree species and forest management conditions, including a young beech managed forest (Plot #1), a virgin beech forest (Plot #2), and four managed old beech forest plots (Plots #3-6) subjected to different anthropogenic influences. To assess these coenopopulations' ontogenetic and vitality structures, we employed a range of scientific methodologies, including geobotanical description, morphometry analysis, complex vitality assessment, and statistical data analysis. Morphometric analyses allowed us to discern the characteristic size parameters of S. holostea plants within each specific habitat. Notably, our findings revealed that the ontogenetic spectra of S. holostea in areas varying in the intensity of anthropogenic influence exhibited incompleteness, except in the virgin forest plot, where all ontogenetic stages were observed. We conducted a factor analysis to gauge vitality, identifying critical morphological parameters unique to each population. Our results indicated a pronounced level of resilience in coenopopulations residing in areas devoid of forestry activities. Specifically, five of the six S. holostea populations were classified as having low vitality (class c). In contrast, the highest vitality class (class a) was predominantly observed among the populations residing in the virgin forest. This study, utilizing S. holostea as an exemplar species, highlights the considerable disruption that forestry management imparts upon the herbaceous layer of forest ecosystems and underscores the resultant degradation in population quality.

CONTEXT: The pasture-woodlands of Central Europe are low-intensity grazing systems in which the structural richness of dynamic forest-grassland mosaics is causal for their high biodiversity. Distinct mosaic patterns in Picea abies- and Fagus sylvatica-dominated pasture-woodlands in the Swiss Jura Mountains suggest a strong influence of tree species regeneration ecology on landscape structural properties. At the landscape scale, however, cause-effect relationships are complicated by habitat selectivity of livestock. OBJECTIVES: We asked which tree species regeneration traits and what kind of feedbacks among local-scale vegetation dynamics and landscape-scale herbivore behavior are causal for the contrasted landscape structural characteristics of Picea- and Fagus-dominated pasture-woodlands. METHODS: We performed simulation experiments of mosaic pattern formation in both pasture-woodland types. The regeneration traits, namely dispersal distance, resistance to browsing and tolerance to shade, and the rules for habitat selection of cattle were modified and the corresponding shifts in landscape structure were analyzed. RESULTS: Dispersal distance showed a significant, but only local, effect promoting forest fringe formation. Saplings’ resistance to browsing mainly determined overall tree cover, but did not influence landscape structure. At the landscape scale, both shade tolerance of saplings and selective habitat use by cattle were responsible for forest-grassland segregation: high shade tolerance triggered segregation, whereas non-selective habitat use hindered it. CONCLUSIONS: Existing local-scale theory on pasture-woodland dynamics is complemented by an herbivore-vegetation feedback among spatial scales. In low-intensity pastures, where large herbivores are preferentially “grazers” and trees form dense canopies, an intrinsic trend towards forest-grassland segregation at the expense of forest-grassland ecotones is predicted.

Vegetation-plot resurvey data are a main source of information on terrestrial biodiversity change, with records reaching back more than one century. Although more and more data from re-sampled plots have been published, there is not yet a comprehensive open-access dataset available for analysis. Here, we compiled and harmonised vegetation-plot resurvey data from Germany covering almost 100 years. We show the distribution of the plot data in space, time and across habitat types of the European Nature Information System (EUNIS). In addition, we include metadata on geographic location, plot size and vegetation structure. The data allow temporal biodiversity change to be assessed at the community scale, reaching back further into the past than most comparable data yet available. They also enable tracking changes in the incidence and distribution of individual species across Germany. In summary, the data come at a level of detail that holds promise for broadening our understanding of the mechanisms and drivers behind plant diversity change over the last century. Measurement(s) vegetation-plot resurvey data of vascular plant species Technology Type(s) vegetation-plot records Factor Type(s) Cover of species in plots Sample Characteristic - Organism Vascular plant species Sample Characteristic - Environment Terrestrial habitats Sample Characteristic - Location Germany

This chapter explains changing architecture and priorities for UN peacebuilding. Member states have advanced in assimilating the conceptual framework of sustaining peace, including through high-level meetings, retreats, and seminars to identify how to improve implementation. The latter attracted broad participation from member states, reaffirmed support for peacebuilding and sustaining peace, and confirmed the importance of synergies among the principal organs and the PBC. In addition, the assembly's president convened an April 2018 high-level meeting on peacebuilding and sustaining peace to focus on the Secretary-General's January 2018 report. There also was more engagement between ECOSOC and the PBC, as illustrated by the meeting held between both bodies in November 2018, on the linkages between climate change and challenges to peacebuilding and sustaining peace in the Sahel. There now is certainly a better understanding of the role of peacebuilding or sustaining peace in the broader agenda of the United Nations; stated differently, there has been progress in articulating a conceptual framework.