Shift in plant-soil interactions along a lakeshore hydrological gradient

Area of Science:

• Wetland ecology
• Soil science
• Biogeochemistry

Background:

• Wetlands bridge aquatic and terrestrial environments, with hydrology critically impacting plant communities and soil processes.
• Understanding plant-soil interactions across wetland hydrological gradients is vital for effective management and adaptation.
• Limited knowledge exists on how hydrological changes influence these complex interactions.

Purpose of the Study:

• To investigate plant-soil interactions along a hydrological gradient in Neuchâtel lake wetlands.
• To relate vegetation composition, plant traits, and soil properties (physicochemical, microbial, enzymatic) to varying flood frequencies.
• To inform wetland management and lake level regulation strategies.

Main Methods:

• Field study on the southeastern shore of Neuchâtel lake, Switzerland.
• Analysis of vegetation composition, aboveground/belowground plant biomass, and C, N, P concentrations.
• Assessment of soil physicochemical properties, microbial biomass, and enzymatic activities across different soil layers and hydrological zones.

Main Results:

• Plant biomass and nutrient concentrations generally decreased from frequently flooded to non-flooded zones.
• The soil organic layer consistently showed higher nutrient concentrations and enzymatic activities than deeper layers.
• Soil organic layer characteristics declined along the hydrological gradient from lakeshore to upland.

Conclusions:

• The plant-soil system in frequently flooded areas showed no nutrient limitation.
• Nitrogen limitation was observed in transitional zones, and nitrogen and phosphorus co-limitation in non-flooded upland zones.
• Findings provide critical data for optimizing lake level regulation based on hydrological thresholds and stakeholder needs.