Understorey plants in space and time: Impact of enhanced forest structural heterogeneity on plant community dynamics and ecosystem stability

• Applicants: Professor Dr. Andreas Fichtner; Professor Dr. Goddert von Oheimb
• Subject Area: Forestry
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 459717468

Spatio-temporal dynamics in forest structure are expected to strongly influence plant diversity, community assembly processes, and biodiversity-stability relationships in forest understories. Yet, empirical evidence from real-world experiments beyond the local scale remains limited. This subproject aims to address this gap by investigating how an enhancement of structural heterogeneity in forest landscapes shapes the trajectories of understorey plant communities over more than a decade across spatial scales, and how these patterns affect the temporal stability of community functioning both above- and belowground. First, we will examine how enhanced structural heterogeneity between forest patches affects the temporal dynamics of understorey plant communities in terms of taxonomic, phylogenetic, and functional diversity across spatial scales, and how these changes relate to temporal variation in canopy structure and microclimate. Assessments of temporal shifts in metacommunity dynamics between homogeneous and heterogeneous forest landscapes will provide mechanistic insights into understorey community trajectories. Second, based on the spatial insurance hypothesis, we will evaluate how changes in understorey plant diversity across spatial scales affects the temporal stability of shoot and root biomass production and the underlying mechanisms, such as species and spatial asynchrony. We will continue vegetation surveys as well as functional trait and biomass measurements (both above- and belowground), combined with new measurements of root dynamics and distribution. Together, these efforts will provide a unique long-term time series on understorey plant communities. We will further extend our time series on epiphytic and epixylic bryophytes and lichens, creating complementary long-term datasets that will be shared with the entire research unit and directly support its synthesis work. Overall, by integrating temporal and spatial perspectives, this subproject aims to advance our understanding of how heterogeneous forest landscapes sustain biodiversity over time, thereby supporting ecosystem stability.

• DFG Programme: Research Units
• Subproject of: FOR 5375: Enhancing the structural diversity between patches for improving multidiversity and multifunctionality in production forests
• International Connection: Netherlands
• Co-Investigator: Dr. Sebastian Dittrich
• Cooperation Partner: Professor Dr. Benjamin Delory