Biology subjects

Schweiger, A. H.

Publications and source records attributed to Schweiger, A. H..

3 recordsLinked to original sources

bioRxiv2026

Long-term vegetation change in protected calcareous fens is driven by land-use change and management abandonment

AimsHistorical land use has shaped plant diversity in Central Europe for centuries, and many plant communities of high conservation value have been maintained by long-term traditional management. This study assesses how changes in land use over the past century have affected plant community composition and vegetation-based ecological indicator values in the management-dependent mire community Primulo-Schoenetum ferruginei. LocationSouth-western Germany. MethodsWe conducted repeated vegetation surveys at multiple sites, comparing historical records with recent surveys spanning up to 97 years. Changes in species composition were analysed using multivariate approaches, and shifts in habitat conditions were assessed using indicator values for nutrients, temperature, light and mowing frequency. Information on historical management was compiled from original vegetation sources, while current management data were obtained from responsible conservation authorities and regional administration. ResultsFen communities showed pronounced temporal changes in species composition. Community turnover was significantly associated with shrub encroachment, mowing frequency, hay transfer and early mowing. In addition, species-based indicator values suggested increasing nutrient availability and temperature affinity of the vegetation, alongside decreasing light availability. Disturbance indicators pointed towards less frequent but more severe disturbance regimes in contemporary compared to historical vegetation. ConclusionsOur results demonstrate that management-dependent fen communities are highly sensitive to changes in land-use regimes, i.e. disturbance frequency and severity that is indicated to have significantly changed in the protected areas in this study. These findings highlight the importance of maintaining traditional land management practices when aiming to maintain biodiversity in calcareous fens.

ecology↗

bioRxiv2024

Environmental versus litter traits as drivers of microbial decomposer functions

Plant litter decomposition is a key ecosystem process with significant implications for global carbon cycling, soil fertility and plant productivity. Given that microbial decomposers are the main players in the decomposition process, it is surprising how little is known about their functional diversity in different habitats or their ability to respond to environmental changes. To fill this knowledge gap, we conducted a litterbag decomposition experiment along a pronounced climate and vegetation gradient in the Chilean Coastal Cordillera (26{degrees}S to 38{degrees}S), ranging from hyper-arid to temperate, using mixtures of four plant species, native to the respective ecosystems. We analyzed potential decomposition functions of bacterial and fungal litter communities along with their biotic (litter traits) and abiotic (meteorological conditions and soil properties) environments, to determine the relative importance of these environmental factors for microbial community functioning. We also tested the impact of the functional diversity of the decomposer communities (i.e., the diversity of decomposition related functions) on litter mass loss. Functional composition was related most strongly to the temporal variation of precipitation and radiation, explaining about 19 % and 6 % of variation in bacteria and fungi, respectively. In contrast, functional diversity was quite strongly related to litter chemical traits (C:N, C:P, tannins, phenols). Litter mass loss after six months of decomposition was not correlated to the functional diversity of decomposer communities but increased with the presence of habitat generalists like Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes. Taken together, these results highlight i) the interplay between abiotic factors and chemical litter traits on litter microbial functions and functional diversity and ii) the importance of microbial generalists for litter decomposition across different ecosystems. These results enhance our ability to predict changes in microbial decomposer communities and litter decomposition under future climate-change scenarios.

ecology↗

bioRxiv2023

Reassessment of the risks of climate change for terrestrial ecosystems

Forecasting the risks of climate change for species and ecosystems is necessary for developing targeted conservation strategies. Previous risk assessments mapped the exposure of the global land surface to changes in climate1-4 However, this procedure is unlikely to robustly identify priority areas for conservation actions because non-linear physiological responses and co-limitation processes ensure that ecological changes will not map perfectly to the forecast climatic changes. Here, we combine ecophysio{-}logical growth models of 135,153 vascular plant species and plant growth form information to transform ambient and future climatologies into phytoclimates, which describe the ability of climates to support the plant growth forms that characterise terrestrial ecosystems. We forecast that 33% to 68% of the global land surface will experience a significant change in phytoclimate by 2070 under RCP 2.6 and RCP 8.5, respectively. Novel phytoclimates without present-day analogue are forecast to emerge on 0.3-2.2% of the land surface, and 0.1-1.3% of currently realised phytoclimates are forecast to disappear. Notably, the geographic pattern of change, disappearance and novelty of phytoclimates differs markedly from the pattern of analogous trends in climates detected by previous studies1,3,4, thereby defining new priorities for conservation actions and highlighting the limits of using untransformed climate change exposure indices in ecologicaI risk assessments. Our findings suggest that a profound transformation of the biosphere is underway and emphasise the need for a timely adaptation of biodiversity management practices.

ecology↗