A research team led by Prof. ZHU Yongguan, a member of the Chinese Academy of Sciences (CAS) at the CAS Research Center for Eco-Environmental Sciences, has identified the mechanisms by which sponge city construction significantly enhances urban plant diversity, according to a study published in Cell Reports Sustainability on January 27.

This finding frames China's Sponge City Program (SCP) as a dual-benefit solution that synergizes stormwater management with biodiversity enhancement. The national initiative emulates natural water cycle processes to regulate stormwater via green infrastructure—including rain gardens, bioswales, permeable pavements and wetland restoration—with the goals of mitigating urban flooding, improving water quality and bolstering ecological resilience.

As the world's largest government-led initiative focused on retrofitting small-scale urban green spaces (UGS), the SCP is crucial for urban flood resilience. Yet its broader ecological potential had long remained unclear.

To address this knowledge gap, the research team conducted a multi-scale analysis in the 22.27-square-kilometer SCP demonstration zone in Wuxi City, where 1,973 sponge city green infrastructure facilities and 58 related projects were implemented between 2020 and 2023.

The study shows that diversifying plant species in such features as rain gardens and bioswales can raise plant richness by more than 50 percent, affirming the SCP's value as a tool for fostering urban nature beyond its core flood control function.

To maximize these ecological benefits, the researchers call for transdisciplinary collaboration to achieve three key objectives: integrate SCP green spaces into city-wide ecological networks; design such green infrastructure for multi-functional use; and leverage linear green spaces (e.g., along roads and rivers) as potential ecological corridors.

These insights help align urban development with China's commitments under the Kunming-Montreal Global Biodiversity Framework (GBF). By defining key prerequisites in governance, monitoring and adaptive design, the study provides actionable strategies for cities across Asia and the rest of the world to build flood resilience and enhance urban biodiversity simultaneously.