Impact of Water Sediment Quality on Germination of Submerged Aquatic Plants in Flemish Streams

TL;DR

This study explores how sediment contamination in Flemish streams affects the germination of underwater plants and finds that poor sediment quality can hinder plant recovery.

Contribution

The study introduces a novel combination of mesocosm experiments and historical data to assess sediment contamination's impact on macrophyte germination.

Findings

Higher sediment contamination levels reduced seedling emergence in controlled experiments.

Historical data showed a weak link between sediment quality and macrophyte presence, suggesting other factors also play a role.

Abstract

Submerged aquatic macrophytes play a key role in stream ecosystems, but their recovery in historically degraded Flemish streams is often limited. This study investigates whether sediment contamination constrains natural macrophyte germination and early seedling establishment. To address this knowledge gap, we combined a controlled mesocosm experiment with an analysis of long-term monitoring data from Flemish streams. The mesocosms showed that higher levels of sediment contamination reduced seedling emergence, indicating that sediment quality can directly inhibit germination and early establishment. In addition, historical monitoring data revealed only a weak association between sediment quality and macrophyte occurrence, pointing to the importance of interacting drivers such as hydrology, light availability, and habitat structure. Together, these findings highlight sediment contamination as a context-dependent but relevant barrier to macrophyte recruitment, underscoring the need to integrate sediment quality into broader restoration planning for streams in Flanders and abroad.

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