Exotic Laguncularia racemosa drives rapid shifts in pond-to-mangrove restoration communities

The global degradation of mangrove ecosystems necessitates urgent restoration efforts. In China and many Southeast Asian regions, pond-to-mangrove restoration (PTMR) has become a key method for mangrove recovery. PTMR involves creating suitable habitats for mangroves through artificial terrain modification and planting. However, an overlooked issue is whether invasive exotic species benefit from PTMR. This study examines plant communities in a typical PTMR area, comparing community composition at four (PTMR4) and eight (PTMR8) years post-restoration. Results show that the exotic species Laguncularia racemosa rapidly increases in PTMR areas, significantly inhibiting native species growth and altering community composition. The relative abundance of L. racemosa rose from 8% at PTMR4 to 57% at PTMR8. By PTMR8, L. racemosa was taller than native species, with many seedlings present. Given the rapid growth and reproductive capacity of L. racemosa, and the high hydrological connectivity of mangrove wetlands, we recommend incorporating exotic species monitoring during PTMR. This study highlights the threat of biological invasions to ecological restoration projects, not just mangrove restoration. It emphasizes the need to prevent invasive species introduction during early restoration stages.