2d: Ecological Scaling

2d:     Ecological Scaling

Conveners:     Yann Hautier (Utrecht University)

                        Franciska de Vries (University of Amsterdam)

1. The Salt Challenge: Building Wetlands in a Changing Climate

Eleonora Saccon, Suzanne Hulscher, Tjeerd Bouma, Johan van de Koppel, Royal Netherlands Institute for Sea Research

Restoring and creating tidal freshwater wetlands is increasingly important, as these resilient ecosystems offer diverse services. However, salt intrusion—driven by climate change and human activities—limits the effectiveness of these efforts. Achieving restoration and conservation goals depends on understanding how protected, restored, and newly created wetlands respond to increasing salinity.

To clarify these dynamics, we developed numerical models to explore how freshwater wetlands will develop with increasing salinity. Our models reveal that current protection and restoration practices may inadvertently increase vulnerability to salt intrusion, underscoring the need for adaptive strategies that enhance resilience. We propose restoration and management strategies to improve wetland resistance and resilience to increased salinity, ensuring these ecosystems continue to function and support ecological and human communities under changing conditions.

2. Relationships between plant traits and soil properties differ between wetlands with different water level management

Emma Polman, Kenneth Rijsdijk, Perry Cornelissen & Franciska de Vries,  University of Amsterdam

Water level management is an important strategy for influencing vegetation development and creating suitable habitat for wildlife in managed wetland systems. Water level dynamics also affect soil carbon and nutrient cycling through changes in abiotic soil properties, plant traits and soil microbial communities. We hypothesize that seasonal inundated grasslands are dominated by plant communities with fast-growth related plant traits and bacterial dominated microbial communities, leading to lower carbon and nutrient stocks compared to non-inundated grasslands. To test this hypothesis, we compared soil and vegetation on winter inundated and non-inundated grasslands in a Dutch managed wetland area. Winter inundated grasslands had plant communities with more slow-growth related traits and soil microbial communities more dominated by fungi, but we found no differences between soil carbon and nutrient stocks. These findings show that water level management is important for plant and soil communities but not for altering carbon and nutrient stocks.

3. The Dutch EcoFracNet: unravelling biodiversity patterns across spatial scales in the Netherlands

Jonas Lembrechts, Utrecht University

In this talk, I’ll introduce the Dutch branch of the international Ecological Fractal Network (EcoFracNet), which captures biodiversity patterns across scales in typical Dutch landscapes to better understand spatial and temporal biodiversity variation. Building on EcoFracNet’s standardized, fractal-based monitoring, this network uses a systematic array of 1x1 meter plots to assess plant diversity and microclimate, with room for other ecosystem components and functions. Established in 2024, the Dutch EcoFracNet network addresses key questions on the spatiotemporal scales at which biodiversity varies and the impact that land use might have, revealing the scale at which conservation efforts are most effective. Additionally, it explores roles of landscape features traditionally overlooked for biodiversity conservation, like gardens, farms, and campuses, and compares biodiversity variation in the Netherlands with other regions. I’ll conclude with a call for collaborations across the Netherlands to implement this design in as many sites as possible.

4. The Role of Area and Beta Diversity in Scaling Diversity-Stability Relationships

Julia Mayr, Kathryn E. Barry, Yann Hautier, Utrecht University

Managing biodiversity for ecosystem stability amid environmental change is crucial, but local scale knowledge often fails to align with regional management needs. The variation in species composition among communities (beta diversity), plays a key role in stabilizing functions at the larger spatial scale by enhancing spatial asynchrony—where different communities respond differently to environmental fluctuations. Importantly, both beta diversity and spatial asynchrony are inherently scale dependent, but the role of spatial extent in this relationship, and consequently, in large scale stability remains unquantified. Using simulated landscapes from a highly replicated grassland biodiversity experiment, we find that the contribution of beta diversity and spatial asynchrony to the temporal stability of biomass production at the larger spatial scale depend on both local diversity and spatial extent. Our results underscore the need for multi-scale conservation strategies to ensure ecosystem stability.

5. Effects of biotic homogenization on community assembly and biomass production in an β-diversity grassland experiment

Fons van der Plas, Justus Hennecke, Lea von Sivers, Alexandra Weigelt, Christian Wirth, Kathryn E. Barry, Wageningen University & Research

Various experiments have shown that local, within-patch losses of plant species (α-diversity loss) decreases plant productivity. However, species loss also happens at larger spatial scales (γ-diversity loss), often because species compositions homogenize across patches (β-diversity loss). Here, we experimentally manipulated grassland plant β-diversity by setting up 56 plots, each divided into four sub-plots with different soils, and either the same (low β-diversity) or different (high β-diversity) species compositions. We hypothesized that high β-diversity would increase biomass production through two mechanisms: 1) species sorting and 2) gains in α-diversity over time. After four years, we found that while different species became dominant in different soil types (indicating species sorting), this sorting did not increase biomass production. In contrast, high sown levels of β-diversity increased biomass production through increases in α-diversity over time. Hence, our results provide the first experimental evidence that β-diversity loss decreases biomass production, highlighting the importance of larger-scale biodiversity for ecosystem functioning.