Carbon sequestration efficiency of urban mangroves: The role of native vs. introduced species

This study evaluates species-specific differences in aboveground carbon sequestration among native and introduced tree species in an urban mangrove ecosystem of Guayaquil, Ecuador. Field measurements and allometric models were applied to quantify biomass and carbon storage of Rhizophora (R.) mangle, Rhizophora × harrisonii, and the introduced ornamental Ficus (F.) benjamina within the Wildlife Production Reserve “Manglares El Salado” (RPFMES). Using species-specific equations and statistical analyses (ANOVA and Tukey's tests), we compared diameter at breast height (DBH), aboveground biomass (AGB), and carbon stocks across species. Results show that R. mangle had the largest DBH and the highest mean aboveground carbon stock (19279 g), followed by R. × harrisonii, while F. benjamina exhibited lower and more variable values. Although DBH differences were significant with a p value at 0.0451 (the p-value serves to quantify the strength of the evidence against the null hypothesis), biomass and carbon stock variations were not (p = 0.103), suggesting that native mangroves maintain structural advantages and consistent carbon accumulation even under urban stress. These findings underscore the superior ecological performance of native Rhizophora species for long-term blue-carbon storage and resilience, emphasizing their prioritization in restoration planning. Conversely, the introduced F. benjamina contributes minimally to carbon sequestration in estuarine environments due to its limited adaptation to saline, anoxic soils. This research highlights the importance of species selection in urban mangrove management to maximize carbon capture and ecosystem functionality.