Leaf area and pubescence drive sedimentation on leaf surfaces during flooding

Area of Science:

• Environmental Science
• Ecology
• Biogeochemistry

Background:

• Accelerated soil erosion and agricultural intensification increase stream sediment and nutrient loads, leading to eutrophication and siltation.
• Floodplains are vital for mitigating these issues through sediment and nutrient retention via water filtration.
• Understanding how plant leaf traits influence leaf surface sedimentation is crucial for optimizing floodplain functions.

Purpose of the Study:

• To investigate the influence of various leaf traits on fine sediment accumulation on plant leaves.
• To quantify the extent to which leaf traits explain variations in leaf surface sedimentation.
• To identify specific leaf traits that maximize sediment retention on floodplains.

Main Methods:

• A flume experiment was conducted exposing leaves from 30 plant species to an artificial flood.
• Leaf surface sedimentation was measured after 24 hours.
• Key leaf traits including area, length, perimeter, pinnation, pubescence, roughness, flexibility, and wettability were analyzed for their influence on sedimentation.

Main Results:

• Leaf traits collectively explained 65% of the variation in fine sediment deposition on leaves.
• Adaxial pubescence (hairs) and leaf area were the most significant drivers of sedimentation.
• Hairy leaves accumulated more sediment per unit area, while larger, hairless leaves showed decreased sedimentation due to increased turbulence.

Conclusions:

• Plant leaf traits play a significant role in regulating fine sediment accumulation in aquatic ecosystems.
• Leaf traits, particularly pubescence and leaf area, can be leveraged to select plant species for enhanced sediment retention on floodplains.
• Optimizing plant species composition based on leaf traits can improve the ecosystem service of sediment removal in river systems.