Seed Predation and diversity of arthropod communities in Response to land-use INTensity (SPRINT).

• Applicant: Dr. David Ott
• Subject Area: Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions ; Ecology of Land Use
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 433188984

Land-use intensification is an important driver of biodiversity loss in terrestrial ecosystems. Studies in grassland ecosystems have shown that changes in local plant species richness can have bottom-up effects on higher trophic levels, biotic interactions and associated ecosystem processes. In turn, one of these processes, the post-dispersal seed predation, can exhibit severe effects on plant species demography, ultimately altering species diversity and community structure in a system. Up to date, we lack a clear understanding how seed predation, and the underlying communities react to changes in grassland management along a full land-use gradient. So far, progress has been limited by the divide between biodiversity experiments that manipulated species richness and observational studies in existing grassland communities. A new multisite grassland experiment aims to overcome these limitations by experimentally increasing or decreasing management intensity of single factors of land-use. In addition, local plant species richness will be manipulated by seed addition. The new experiment thus serves as an important bridge between observational and experimental grassland biodiversity studies. In our proposed project, we will make use of this new experiment working on its full set of 75 plots. We will study the relationships between the plant community and ground-dwelling arthropod communities and the ecosystem process of seed predation in response to changes in land-use intensity and vegetation characteristics by: (i) monitoring changes in arthropod species- and functional group richness, trait diversity and community composition in all three Exploratories. This will allow for the first time to disentangle effects of different components of land-use, i.e. management such as mowing and grazing and fertilization. (ii) quantifying the ecosystem process rate of seed predation and disentangling the relative contribution of different taxa of consumers in additional experiments. To achieve this goal, we will conduct a novel field experiment under real-world conditions embedded in the new multi-site land-use grassland experiment in the Hainich-Dün Exploratory.(iii) we will assess qualitatively and quantitatively the feeding preferences of arthropod seed predators in with additional measures. We will conduct trait measurements such as body size and mandibular width by using novel HD microscope techniques. Measurements of elemental contents of both consumer and resource species, will yield novel insights in feeding interactions.The project will be tightly integrated into other projects studying within the Biodiversity Exploratories. Overall, our pioneering approach combines biodiversity manipulations and measures of a process rate with a real-word, land-use context, and will aid to fill the gap in understanding the role of plant diversity and land-used intensity for seed predation and vice versa.

• DFG Programme: Infrastructure Priority Programmes
• Subproject of: SPP 1374: Biodiversity Exploratories