Estoque de carbono azul da biomassa acima do solo em um manguezal em recuperação na APA do rio Pacoti, Ceará, Brasil

Abstract

Mangroves are coastal ecosystems that capture significant amounts of atmospheric carbon and store it in their vegetation and soil, being capable of storing up to five times more blue carbon than other highland ecosystems. In the context of the current climate crisis, these environments can act as natural solutions to mitigate global warming, if they are preserved and restored. Despite Brazil being the second country with the largest mangrove extension in the world, the number of research and projects on quantifying carbon content in these environments is still low. The present study aimed to estimate the blue carbon stock of the mangrove forest in the Pacoti River Environmental Protection Area (APA), Ceará, Brazil, for this the current stock of an area of juvenile mangrove forest, in the process of ecological recovery after human degradation, was compared with other preserved areas in the surrounding area. In addition, the temporal variation in carbon storage between 2019 and 2022 in the same area that is undergoing recovery was analyzed. Three sample areas were defined for comparison: Area A, which is a preserved mangrove forest further from the river; Area B, which represents the young forest under development; and Area C, which is also a preserved forest, and borders the edge of the river. In each area, five quadrants of 5 x 5 meters were demarcated, and data on diameter at breast height (DBH) were collected in each one, as well as the identification of mangrove plants at species level. Consequently, these data were applied to specific allometric equations to obtain biomass and then converted into carbon content. As a result, the mangrove vegetation of the Pacoti River APA has an average blue carbon stock estimated at 80.25 Mg C/ha and 45.42 Mg C/ha, according to different versions of the equations. Area A presented an average of 121.88 and 62.75 Mg C/ha. While Area B, representing the forest in recovery, had an average of 16.39 Mg C/ha. Area C, on the other hand, recorded average values similar to those of the first area, with 102.49 and 57.12 Mg C/ha. Therefore, it is noted that the site studied has significant amounts of carbon in its mangrove plant reserve, even though it is a mangrove located in a semiarid region. Data like these strengthen the justification for preserving mangroves and encourage investment in more projects to recover degraded areas, in such a way that they can be one of the solutions to mitigate the effects of climate change.