WaterWeb: Exploring land-freshwater dynamics under global change through the lenses of biodiversity

• Applicant: Dr. Maria Alejandra Parreno
• Subject Area: Ecology of Land Use ; Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 568975044

Land-freshwater interactions are crucial to the ecosystem functioning in grasslands. In riparian areas, energy and nutrients are constantly exchanged between water and land through species interactions and processes such as floods and sediment deposition. Land use intensification and the landscape's homogenization alter riparian areas' structure and water quality composition, which results in cascading effects on biodiversity and ecosystem functions such as soil fertility, productivity, and nutrient cycling. Despite their importance, land-freshwater interactions in agricultural grasslands remain underexplored and isolated in disciplinary focus research. WaterWeb aims to fill this gap by exploring freshwater sources and associated riparian biodiversity in 36 grassland plots across three sites in Germany, along a gradient of land use intensity over three years. We hypothesize that freshwater bodies near less intensively managed plots will have higher water quality and greater geomorphological complexity and support healthier and richer riparian communities than those in intensively managed plots. Biodiversity, particularly of aquatic and semi-aquatic macroinvertebrates, will, in turn, be associated with enhanced ecosystem functions in the surrounding land, such as higher soil fertility and productivity. To test these hypotheses, WaterWeb will apply an interdisciplinary array of methods to characterize riparian areas: hydrological mapping using GIS, year-round water quality monitoring with physicochemical sensors, assessment of amphipod communities as bioindicators and eDNA metabarcoding to characterize wider macroinvertebrate communities otherwise not captured by traditional sampling methods. Spatial analyses and structural equation modeling will be used to test causal pathways of the hypothesized relations between land use intensity, water quality, biodiversity, and terrestrial functions. Preliminary analyses indicate that proximity to freshwater significantly influences insect and plant community composition and is linked to higher aboveground productivity. The novel data collected and analyzed through WaterWeb will shed light on the mechanisms behind these processes and potentially explain inter-plot and inter-annual variability observed in ecosystem functions. Despite the fact that most experimental plots are within 500 m of a freshwater body, WaterWeb will generate the first datasets characterizing their status and the composition of the riparian biodiversity of the Biodiversity Exploratories. We will provide concrete indicators, such as water chemical profiles and functional biodiversity metrics, that can be used to assess ecosystem health and inform integrative land use management decisions. WaterWeb´s research and outreach will set a strong foundation for blue-green research in the Biodiversity Exploratories.

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