Search

Questions: Mountain grasslands can be strongly affected by extreme droughts such as those related to climate change. What are the impacts of extreme droughts on community composition, diversity, Ellenberg indicator scores and species groups in oligotrophic montane Nardus grasslands, and what are the associated mechanisms of vegetation change? Location: Rhön Mountains, Germany. Methods: Over three consecutive years, we investigated the effects of yearly droughts (April–August) in an experimental setup with rainout shelters. Owing to the coincidence of ambient extreme dry conditions in those years and our artificial rainfall reduction, we evaluated the contribution to community change of ambient drought conditions and the treatments. We analysed changes in community composition by applying redundancy analysis to species differences in comparison with the pretreatment year, and used mixed‐effects models to test for changes in community‐weighted means of Ellenberg indicator scores, sociological and functional groups. Results: We found significant changes in species abundance and community structures in response to drought. Evenness increased, but species richness remained rather stable over time. Ellenberg indicator scores for temperature and nitrogen increased, whereas the score for moisture decreased. Simultaneously, dominant species declined and subdominants increased. Changes occurred with a time lag and were driven largely by the high ambient drought level and less by the artificial treatments. Conclusions: Our results show that drought‐related changes in community composition in Nardus grasslands occur across community structures, characteristic species, and species groups. The post‐drought recovery of the community is shaped by community filters, which in particular allow subdominants to take advantage of newly available niches in the matrix, even if they lack strong drought tolerance. Our findings indicate a certain resilience of the community to droughts related to climate change, which suggests that the observed changes should not lead to an accelerated short‐term decline in these grasslands, but that this cannot be excluded in the long term. [ABSTRACT FROM AUTHOR]

Questions: Which trends and patterns of community change occurred in Nardus grasslands over recent decades in parts of the Continental biogeographic region of Germany? Are patterns and trends consistent across two study regions? Do impacts of environmental changes on Nardus grasslands in Central Europe correspond to those identified in the European Atlantic biogeographic region? Location: East Hesse Highlands, Germany. Methods: In 2012–2015, we re‐surveyed quasi‐permanent plots that had been initially surveyed between 1971 and 1987, and re‐measured soil parameters. We tested for differences in species frequency and cover, mean Ellenberg indicator values, species richness, and soil variables. Nitrogen and sulphur deposition data were analysed to evaluate possible effects of atmospheric pollutants. We used regression and redundancy analyses to identify environmental drivers responsible for changes in species composition. Results: Across regions, we found significant increases in soil pH, Ellenberg R and N indicator values, plant nutrient indicators, forbs, species of agricultural grasslands and of fallows. By contrast, the C:N ratio, Nardus grassland specialists, low‐nutrient indicators, and graminoids declined. Changes in species composition were related to changes in pH and management. There was a strong decrease in sulphur and a moderate increase in nitrogen deposition, whose local‐scale pattern did not correlate with changes in soil parameters. However, there was an effect of local NHy changes on species composition. Conclusions: The findings indicate significant overall eutrophication, a trend towards less acidic conditions and insufficient management, which are widely consistent across our study regions and correspond to recent reports of vegetation changes and recovery from acidification in the Atlantic biogeographic region. We assume the reduced sulphur deposition during recent decades to be a major driver of these changes, combined with increased nitrogen deposition and reduced management intensity. This suggests a large‐scale validity of processes that influenced changes in Nardus grasslands of Western and Central Europe. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Highlights • We propose an indicator-based framework to assess landscape's cultural heritage. • The framework joins historic land use and element indicators for cultural heritage. • Each indicator shows different spatial distributions of Scottish cultural heritage. • The use of single indicators simplifies complex cultural heritage values. Abstract The cultural heritage of landscapes makes an important contribution to people's local identity, which enhances the human-nature relationship and informs decision making. However, cultural heritage assessments in the context of cultural ecosystem services are still challenged by the lack of coherent methods to assess the spatial distribution of cultural heritage. This paper addresses the questions: how can complex cultural heritage be captured with objective indicators and how are cultural heritage values spatially distributed in Scotland? The aim of this paper is to develop an indicator-based framework for the mapping of cultural heritage, which will be tested for its applicability by assessing cultural heritage in a Scottish national level case study. The developed hierarchical framework includes both, indicators related to historic land uses (Time Depth) and historic elements (Historic Richness) that are aggregated to a higher methodological level for mapping the spatial distribution of cultural heritage value. The application of the framework in the case study has shown its capability to assess the spatial and temporal distribution of cultural heritage in Scottish landscapes. The results identify landscapes that represent cultural heritage hotspots of Scotland (e.g. crofting landscapes, settlements shaped by early industrialisation or the Drumlin Lowlands). Different landscape units and classes are highlighted by either historic land use or elements, which underline the specific contribution of different indicators to the overall cultural heritage indicator. Land use-based indicators highlight landscapes with early-introduced, medium-dynamic land use patterns, while element-based indicators highlight landscapes with a long tradition of settlements. The proposed framework emphasises the importance of systematic indicators for cultural heritage, which reflect both quantitative and qualitative aspects of human influence on land use and the built environment. These aspects are difficult to include in a single indicator. The findings can improve the integration of cultural heritage values in decision-making processes and the development of more objectively assessable indicators for other cultural ecosystems services. [ABSTRACT FROM AUTHOR]