Introduction of Native Submerged Macrophytes to Restore Biodiversity in Streams.

Streams are biodiversity hotspots that provide numerous ecosystem services. Safeguarding this biodiversity is crucial to uphold sustainable ecosystem functioning and to ensure the continuation of these ecosystem services in the future. However, in recent decades, streams have witnessed a disproportionate decline in biodiversity compared to other ecosystems, and are currently considered among the most threatened ecosystems worldwide. This is the result of the combined effect of a multitude of stressors. For freshwater systems in general, these have been classified into five main pressures: water pollution, overexploitation, habitat degradation and destruction, alien invasive species, and hydromorphological pressures. On top of these direct stressors, the effects of global processes like environmental and climate change must be considered. The intricate and interconnected nature of various stressors affecting streams has made it challenging to formulate effective policies and management strategies. As a result, restoration efforts have not always been successful in creating a large-scale shift towards a better ecological status. In order to achieve an improved status in these systems, situation-specific management strategies tailored to specific stressor combinations may be needed. In this paper, we examine the potential of introducing native submerged macrophyte species to advance the restoration of stream ecosystems. Through successful introductions, we anticipate positive ecological outcomes, including enhanced water quality and increased biodiversity. This research is significant, as the potential success in restoring stream biodiversity not only represents progress in ecological understanding but also offers valuable insights for future restoration and management strategies for these vital ecosystems.