Standing Biomass and Litterfall Production of Reforested Mangroves in Douala-Edea National Park (Cameroon)

Nyamsi-Moussian L , Gordon AN, Essome-Koum GL, Kotte-Mapoko EF, Boubakary B, Konango-Same A, Ngo-Massou VM, Shangguan Z and Wang MY

Published on: 2023-09-27

Abstract

The ecological status of the Reforested Mangrove Areas (RMAs) of Douala-Edea National Park (DENP) remains poorly known despite numerous restoration projects that have been carried out over the last two decades. The objective of this work is to estimate standing biomass and litterfall production of three RMAs of DENP in Bolondo and Yoyo II. Thirty Permanent Sampling Plots (PSPs) of 10m×10m were established such as 15 in RMAs and 15 in their respective natural adjacent vegetation. The height and diameter of individuals were measured. Allometric equations were used to estimate above ground biomass (AGB) and below ground biomass (BGB). One hundred and fifty litter traps (1m×1m) were set up equally in the 30 PSPs. During one year, litterfall was collected monthly, dried, sorted and weighed. The plant species used for reforestation were belonging to Rhizophora genus. Mean diameters, abundances and mean heights were 1.2±0.5 cm, 4000±200 ind./ha and 1.8±0.3 m; 2.58±0.85 cm, 3280±238.74 ind./ha and 5.64±1.87 m; 2.93±1.4 cm, 2160±240.83 ind./ha and 3.34±1.26 m for 3-years, 6-years and 11-years old RMAs, respectively. AGB, BGB and annual dry biomass productions of litterfall were: 11.98±0.76 kg/ha, 13.88±1.3 kg/ha and 40.78±7.42 g/m²/year; 61.18±2.16 kg/ha, 55.19±1.92 kg/ha and 397.75±75.79 g/m²/year; 55.25±2.93 kg/ha, 47.8±1.31 kg/ha and 576.23±106.75 g/m²/year for 3-years, 6-years and 11-years RMAs respectively, which are equivalent to approximately, 12.31±2.19, 52.08±1.6 and 46.26±1.1 kgC/ha of total carbon sink and 18.27±3.48, 179.09±4.44 and 259.3±8.89 kgC/ha/year of total annual litterfall carbon sink, respectively. The highest values of AGB and BGB were obtained with 6-year-old RMA but remained lower than in their natural vegetation. The annual litterfall production was greater in the 11-year-old RMA and, the similarity observed in the annual litterfall production between the 11-year-old RMA and its natural vegetation may be relevant in the evaluation of the term for RMA to reach natural ecological balance.