Synthesis area 4: Model integration - a unified trait-based metacommunity framework

• Applicant: Professor Dr. Bernd Blasius
• Subject Area: Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 379417748

One of the most prominent patterns in ecology is the spatial zonation of species along environmental gradients driven by factors like salinity, elevation, and disturbance. These gradients serve as natural laboratories to study species dynamics and predict their response to environmental change, particularly in highly dynamic coastal ecosystems. An iconic example is the land-sea transition in the German Wadden Sea, the focal study area of DynaCom, where terrestrial and marine food webs converge. While on a larger spatial scale, this landscape is naturally fragmented with terrestrial islands within an otherwise marine environment, on a finer scale the land-sea transition exhibits a nearly continuous gradient, transitioning from submerged mudflats to upper salt marshes, where plant species shift from stress-tolerant pioneers in the lower marsh to competitively dominant species in less stressful zones. Trait-based models offer a powerful approach for capturing these dynamics by linking species-specific adaptations to environmental conditions with dispersal processes across scales. However, existing gradient models often overlook key aspects of coastal systems. They often treat terrestrial and marine systems separately, neglecting the continuum in coastal zones. Many focus on single guilds or trophic levels, failing to capture the complexity of multitrophic interactions. Furthermore, while effective at local scales, they rarely address macro-scale dynamics that connect local processes to broader biogeographical patterns. In the synthesis phase, SYN4 addresses these gaps by integrating previous DynaCom’s modeling efforts into a unified trait-based metacommunity framework. Building on the established model of trait-based metacommunities along stress gradients, this framework will address three objectives: O1. From Land to Sea: Expand models to capture the entire coastal gradient, from mudflats to the upper salt marsh, and use these to explore the effects of stochasticity and positive feedbacks (e.g., sedimentation) to drive sharp ecological transitions in seemingly gradual gradients. O2. Linking Layers: Integrate plant-consumer and size-structured trophic interactions into the models to establish gradient metafoodwebs, as a novel framework for understanding multitrophic spatial dynamics along environmental gradients. O3: Gradients as Islands: Merge local stress-gradient models with macro-scale dispersal dynamics, introducing the concept of meta-gradients that unify island biogeography with trait-based gradient dynamics. This comprehensive framework will leverage extensive empirical data from previous DynaCom phases and generate synthetic time series as benchmarks for analysis. By achieving a mechanistic understanding of metacommunity dynamics in complex, real-world landscapes, SYN4 will address DynaCom's core question: How do spatial and trophic processes interact to shape scale-dependent community ecology in dynamic and highly perturbed landscapes?

• DFG Programme: Research Units
• Subproject of: FOR 2716: Spatial community ecology in highly dynamic landscapes: from island biogeography to metaecosystems [DynaCom]
• Co-Investigators: Professor Dr. Ulrich Brose; Professorin Dr. Ulrike Feudel; Dr. Alexey Ryabov