Masterarbeit

Lindenhof Biodiversity Experiment: a long-term project on biodiversity trends

Saverio Segatto (01/2024-12/2024)

Betreuer: Alessandro Chiarucci, Carl Beierkuhnlein

Biodiversity and ecosystem services have become increasingly relevant in scientific research, thanks to their importance for human well-being and due to the level of threat they are subjected because of the human-induced global changes. Climatic extremes are becoming more frequent and widespread, creating a major challenge for most ecosystems on the planet. An extremely important ecosystem for human activities is grassland. Grassland ecosystem is one of the most widespread ecosystems worldwide and plays a fundamental role in food security. At the same time, it is an ecosystem that can be studied and manipulated in relatively short periods of time. These are the main reasons behind multiple biodiversity grassland experiments around the world, which are aiming to discover what the impacts of climate change on this specific ecosystem are and could, in the future, be. This study is focused on the Lindenhof Biodiversity Experiment, which is an example of this type of biodiversity grassland experiments. It is a 26-year-long project executed by the University of Bayreuth, continuing the former Biodepth European Project and based on the monitoring of 64 grassland vegetation plots. The plots were constantly sampled throughout the years, allowing the formation of a complete and informative dataset. The resulting dataset was then used in this study to understand changes in biodiversity focusing on the following variables: species presence and composition, species-specific cover and species-specific biomass. Data analyses were performed to identify the main trends characterizing the vegetation present on site. Further analyses on the (dis-)similarities within the variables abovementioned were also performed and studied, giving the opportunity for a better understanding of the biodiversity trends of the study site. Number and identity of species, grams of biomass, Jaccard and Bray-Curtis Similarity Indices have been considered in this study case. Thanks to these methods, trends were identified and analysed. The overall number of species present in the area increased through time, while the aboveground biomass produced declined over time. Similarity between different plots and different harvests generally tended to initially increase, and then stabilize, to finally slightly decrease towards the end of the timeseries. Connections to climate and droughts were highlighted and discussed. This should be regarded as an observational study of the considered variables, allowing a better understanding of vegetation dynamics and identifying specific topics where future scientific research on the same experiment, and similar experiments, should focus on.