TITLE:
National Soil Organic Carbon Stocks Inventories under Different Mangrove Forest Types in Gabon
AUTHORS:
Rolf Gaël Mabicka Obame, Neil-Yohan Musadji, Jean Hervé Mve Beh, Lydie-Stella Koutika, Jean Aubin Ondo, Farrel Nzigou Boucka, Michel Mbina Mounguengui, Claude Geffroy
KEYWORDS:
Mangroves Forest, Soil Organic Carbon Stocks, Rizophora Racemose, Avicenia germinans, Gabon
JOURNAL NAME:
Open Journal of Forestry,
Vol.14 No.2,
April
26,
2024
ABSTRACT: Gabonese’s estuary is an important coastal mangrove setting and soil plays a key role in mangrove carbon storage in mangrove forests. However, the spatial variation in soil organic carbon (SOC) storage remain unclear. To address this gap, determining the SOC spatial variation in Gabonese’s estuarine is essential for better understanding the global carbon cycle. The present study compared soil organic carbon between northern and southern sites in different mangrove forest, Rhizophora racemosa and Avicennia germinans. The results showed that the mean SOC stocks at 1 m depth were 256.28 ± 127.29 MgC ha−1. Among the different regions, SOC in northern zone was significantly (p −1) than that in the southern zone (143.19 ± 44 MgC ha−1). At all sites, SOC stocks were significantly higher in Rhizophora racemose (192.2 ± 114.17 MgC ha−1) than in Avicenia germinans (130.12 ± 161.16 MgC ha−1) (p −1) than upper layers (55.42 ± 25.37 MgC ha−1). The study highlights that low deforestation rate have led to less CO2 (705.3 Mg CO2e ha−1 - 922.62 Mg CO2e ha−1) emissions than most sediment carbon-rich mangroves in the world. These results highlight the influence of soil texture and mangrove forest types on the mangrove SOC stocks. The first national comparison of soil organic carbon stocks between mangroves and upland tropical forests indicated SOC stocks were two times more in mangroves soils (51.21 ± 45.00 MgC ha−1) than primary (20.33 ± 12.7 MgC ha−1), savanna and cropland (21.71 ± 15.10 MgC ha−1). We find that mangroves in this study emit lower dioxide-carbon equivalent emissions. This study highlights the importance of national inventories of soil organic carbon and can be used as a baseline on the role of mangroves in carbon sequestration and climate change mitigation but the variation in SOC stocks indicates the need for further national data.