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Restored wetlands reap benefits for climate, drought-resilience after just one year, study shows

Reviving floodplain wetlands slashes carbon emissions by 39% and restores critical ecosystem functions in one year—without the methane spike typically seen in restored peatlands, a new study has found.

Peatlands are known as top carbon sinks, but can after restoration, potentially offsetting short-term climate benefits.

Whereas floodplain, or riparian wetlands, which comprise over half of global wetlands, are often overlooked due to their lower carbon storage.

Now a in the Journal of Environmental Management reveals restored floodplain wetlands can recover within a year and show substantial ecosystem benefits rapidly.

New evidence of rapid and lasting benefits

Study lead-author Dr. Lukas Schuster from RMIT University's Center for Nature Positive Solutions said the scale and pace of ecosystem benefits revealed within just one year of restoration provide a clear case for action.

"Restoring wetlands could be a secret weapon against climate change," he said. "We found managing freshwater wetlands for carbon benefits also boosts flood and drought resilience, highlighting the dual benefits of restoration."

While rewetting and revegetation reduced carbon emissions by 39%, net carbon emissions from the unrestored control wetlands increased by 169% over the monitoring period.

Surface organic carbon stocks, where carbon is stored in plant roots and soil, increased by 12% within one year in restored sites and decreased by 10% in control sites, showing the difference in carbon sequestration potential.

Restored wetlands retained more water in the area, with soil moisture levels increasing by 55%, even after the wetlands themselves had dried, showing drought mitigation potential.

Schuster said increased water retention was linked to improved surface carbon storage in freshwater wetlands.

"We observed a vital link between carbon dynamics and ecosystem function," he said. "Wetlands are nature's purification system, removing nitrogen from waterways and carbon from the atmosphere.

"Now we know even more about the important role they play and how quickly their recovery can be, it's time to act."

Freshwater wetlands, covering less than 10% of Earth's surface, contribute up to 25% of global methane emissions.

Despite this, they hold significant potential as long-term carbon sinks, playing a crucial role in the global carbon cycle.

For the study, researchers compared three degraded wetlands with three restored wetlands along the Loddon River in Victoria, Australia, measuring native plant cover, carbon cycling and ecosystem function.

In the restored wetlands, native plant cover increased significantly, with leaf litter from two dominant native wetland species decomposing more slowly than that of an invasive grass species, suggesting a greater potential for carbon preservation in the soil.

With 45% more nitrogen retained in the soil, restored wetlands showed increased nutrient cycling, which is linked to improved water quality and helps prevent ecosystem disruption like harmful algal blooms, oxygen depletion and contamination.

Schuster said this was important because riparian wetlands are connected to other ecosystems like rivers and streams.

"More nitrogen removed from these wetlands has a positive flow-on effect to connected waterways," he said.

"If you manage the carbon outcome, you get other benefits like drought resilience and healthier farmland where flora and fauna can thrive.

"We've shown wetland restoration pays off, so we hope this study will inform future land management policies."

A floodplain wetland was also monitored six years after it was restored by reintroducing water flow, finding surface organic carbon stocks increased by 53%, demonstrating lasting benefits.

The research was led by RMIT's Center for Nature Positive Solutions, which focuses on addressing urgent environmental challenges from climate change to pollution and biodiversity loss.

Researchers from the Victorian Government's premier biodiversity research institute, the Arthur Rylah Institute for Environmental Research, were also involved.