Context & Ecological Importance of the Charente Wetlands in Nersac
The alluvial floodplains of the Charente river as it traverses the lower perimeter of Nersac form a vital biological ecotone. Characterized by meandering oxbow bends, damp meadows (prairies humides alluviales), secondary drainage ditches, and dense curtains of black alder (Alnus glutinosa) and white willow (Salix alba), these wetlands act as natural flood retention sponges during heavy winter Atlantic rains and critical drought buffers during hot summer months.
However, this delicate ecosystem has faced twin threats: hydraulic destabilization caused by invasive semi-aquatic burrowers and accumulated anthropogenic plastics washed down from upstream industrial zones. Beginning in January 2026, the Amicale des Propriétaires Terriens de Nersac mobilized an intensive volunteer wetland restoration task force to stabilize banks, remove accumulated debris, and restore indigenous flora along three kilometers of communal riverfront.
Operational Phase 1: Selective Regulation of Invasive Semi-Aquatic Rodents
The primary ecological hazard identified during our autumn 2025 inspections was an acute resurgence of coypu (Myocastor coypus). Coypu dig deep, ascending burrow tunnels up to five meters into earthen dikes. When water levels fluctuate, these subterranean tunnels collapse, breaching agricultural floodgates and washing topsoil directly into the river, causing severe siltation of gravel beds required by spawning trout and lamprey.
Under the supervision of our certified trapping delegates, the association deployed sixteen non-lethal selective cage traps across designated ditch intersections. Each trap was equipped with floating pontoons that prevent non-target animals (such as otters, beavers, or European water voles) from being trapped submerged. In accordance with prefectural animal welfare directives, every trap was inspected twice daily at dawn and dusk.
Over a ten-week period between January 15 and March 25, 2026, twenty-eight invasive coypu were humanely captured. Autopsies confirmed that the captured animals carried significant internal parasites, demonstrating that population stabilization also limits pathogenic transmission to domestic cattle grazing on neighboring flood pastures.
Operational Phase 2: Hydraulic Debris Removal & Riverbank Cleanups
Concurrently with pest surveillance, our volunteer teams organized three major weekend cleanup operations. Over forty local volunteers—including property owners, local teenagers, and retired municipal workers—joined forces to clear physical obstructions from watercourses.
Our volunteer squads extracted over 3.2 tons of non-biodegradable waste: discarded agricultural plastics, tractor tires from the 1980s, corrugated iron sheets washed downstream during historic floods, and hundreds of glass bottles. Working in coordination with the technical services of the Mairie de Nersac, all collected waste was sorted and transferred to the intercommunal recycling facility in Angoulême.
Operational Phase 3: Bio-Engineering & Native Willow Replanting
Rather than relying on artificial concrete riprap to repair collapsed embankments, the association utilized soft bio-engineering (génie végétal). In March 2026, volunteers harvested living dormant willow branches from local stands and installed living fascines (tressages de saule) along 420 meters of vulnerable bank.
These woven willow stakes have taken root rapidly, anchoring riverbank sediments with dense root networks while creating submerged shaded pockets that provide refuge for juvenile fish and aquatic invertebrates. Alongside willows, volunteers planted yellow iris (Iris pseudacorus) and carex sedges that naturally filter suspended organic sediments.
Post-Intervention Biological Indicators & Conclusion
Follow-up biological surveys conducted in late spring 2026 showed immediate positive responses. Breeding pairs of common kingfishers (Alcedo atthis) successfully established nesting burrows in the consolidated vertical sandbanks, and odonate surveys registered nine distinct dragonfly species, including the vulnerable orange-spotted emerald (Oxygastra curtisii).
The project demonstrates how targeted civic volunteering, funded transparently through member dues and municipal eco-grants, delivers measurable ecological renewal. The Amicale des Propriétaires Terriens de Nersac will continue monitoring this sector on a monthly basis, ensuring that our wetlands remain clean, structurally secure, and ecologically vibrant.