Vegetation structure, carbon sequestration potential and species conservation in four agroforestry systems in Cameroon (Tropical Africa)

ABSTRACT As the rate of forest degradation continues to rise, agroforestry may serve as a way of conserving species and carbon sinks. The aim of this study was to assess agrobiodiversity and carbon sequestration potential in agrosystems in Cameroon. Three age groups of agrosystems were studied. Data were collected in 100x50 m2 quadrates. Density ranged from 53.17±0.08 to 1463±50.11; basal area from 2.07±0.00 to 988.39±16.13 m2/ha; Shannon diversity from 3.3±0.71 to 3.68±0.72; Carbon storage from 12.1±0.27 to 54.65±1.38 t C/ha for 1-10-year-old agrosystems with lowest values in neem; 34.78±0.87 to 71.34±1.6 t C/ha for 10-20-year-old stands with lowest values in cashew; 28.24±0.04 to 108.51±2.46 t C/ha for +20-year-old stands with highest values in eucalyptus; Carbon sequestration potential from 296.7±1.98 to 859.33±10.01 t CO2eq/ha. The highest carbon stocks were found in eucalyptus stands (p<0.05). Several endogenous species, especially Afzelia bipindensis (EN), Leptoderris ledermannii (EN), Mansonia altissima (EN), Entandrophragma cylindricum (VU), Nesogordonia papaverifera (VU), Quassia sanguinea (VU), Vitellaria paradoxa (VU), Afzelia africana (VU), Erythrina senegalensis (LC), Detarium microcarpum (LC), senna spectabilis (LC), were assessed. Other overexploited species, especially Carissa edulis, Zanthoxylum zanthoxyloides, Adansonia digitata, Securidaca longepedonculata, were assessed as well. The studied systems are significant CO2eq sinks and refuge centre for agrobiodiversity.

摘要
随着森林退化速率持续攀升，农林业或可成为保护物种与碳汇（carbon sink）的有效途径。本研究旨在评估喀麦隆农业生态系统中的农业生物多样性（agrobiodiversity）与碳固存（carbon sequestration）潜力。本研究选取了三个林龄组的农业生态系统开展调查，数据通过100×50平方米的样方采集。
群落密度范围为53.17±0.08至1463±50.11；胸高断面积范围为2.07±0.00至988.39±16.13 m²/ha；香农多样性指数（Shannon diversity）范围为3.3±0.71至3.68±0.72；碳储量方面，1-10年生农业生态系统为12.1±0.27至54.65±1.38 t C/ha，其中印楝（neem）林分的碳储量最低；10-20年生林分的碳储量为34.78±0.87至71.34±1.6 t C/ha，最低值见于腰果（cashew）林分；20年生以上林分的碳储量为28.24±0.04至108.51±2.46 t C/ha，其中桉树（eucalyptus）林分的碳储量最高；碳固存潜力范围为296.7±1.98至859.33±10.01 t CO₂eq/ha。统计检验显示，桉树（eucalyptus）林分的碳储量显著高于其他林分（p<0.05）。
本研究评估了多种本土物种，其中包括：Afzelia bipindensis（濒危，EN）、Leptoderris ledermannii（濒危，EN）、Mansonia altissima（濒危，EN）、Entandrophragma cylindricum（易危，VU）、Nesogordonia papaverifera（易危，VU）、Quassia sanguinea（易危，VU）、Vitellaria paradoxa（易危，VU）、Afzelia africana（易危，VU）、Erythrina senegalensis（无危，LC）、Detarium microcarpum（无危，LC）、Senna spectabilis（无危，LC）。此外，本研究还对Carissa edulis、Zanthoxylum zanthoxyloides、Adansonia digitata、Securidaca longepedonculata等过度开发物种开展了评估。本研究涉及的农业生态系统是重要的二氧化碳当量（CO₂eq）碳汇与农业生物多样性庇护中心。