New insight into blue carbon stocks and natural-human drivers under reclamation history districts for sustainable coastal development: A case study from Liaohe River Delta, China

Blue carbon is a vital aspect of climate change mitigation, which necessitates the identification of stocks and drivers for implementing mitigation strategies. However, reclamation may be among the most invasive forms, and the question of its influence has not been addressed well in blue carbon research. Therefore, the effects of reclamation on carbon stocks and the interaction of crucial drivers from reclamation time areas (1930s, 1960s, 1990s) were evaluated in the Liaohe River Delta (LRD) and compared with natural reserves (core, buffer, experimental areas). Carbon stocks based on InVEST model were lower than preexisting conditions (1.930 × 106 Mg-1.893 × 106 Mg). One-way Analysis of Variance showed that average carbon stocks accumulated 55 years after reclamation and reached the lowest value (13.19 Mg·ha-1) in 85 years. The interaction analysis of dominant drivers affecting carbon showed the difference between reclaimed areas and reserves regarding potential effect pathways. In the 1930s and 1960s reclamation time areas, crop yield and industrial output determined blue carbon by changing NO3--N and AP. In the 1990s reclamation time area, population density played an important role. In defining the impact of vegetation cover on carbon within the reserves, the distance to the coast and residence were significant factors. This study demonstrated that coastal management practices, such as the size of industry and population control and the balanced fertilization techniques in reclamation areas, maintaining adequate vegetation cover in reserve, played a crucial role in the improvement of blue carbon sinks.