Carbon Stocks in the Small Estuarine Mangroves of Geza and Mtimbwani, Tanga, Tanzania

Edmond Alavaisha,Mwita M Mangora

doi:10.1155/2016/2068283

Edmond Alavaisha, Mwita M Mangora

Open Access

https://doi.org/10.1155/2016/2068283

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Abstract

Mangrove forests offer important ecosystem services, including their high capacity for carbon sequestration and stocking. However, they face rapid degradation and loss of ecological resilience particularly at local scales due to human pressure. We conducted inventory of mangrove forests to characterise forest stand structure and estimate carbon stocks in the small estuarine mangroves of Geza and Mtimbwani in Tanga, Tanzania. Forest structure, above-ground carbon (AGC), and below-ground carbon (BGC) were characterised. Soil carbon was estimated to 1 m depth using loss on ignition procedure. Six common mangrove species were identified dominated byAvicennia marina(Forsk.) Vierh. andRhizophora mucronataLamarck. Forest stand density and basal area were 1740 stems ha−1and 17.2 m2 ha−1for Geza and 2334 stems ha−1and 30.3 m2 ha−1for Mtimbwani. Total ecosystem carbon stocks were 414.6 Mg C ha−1for Geza and 684.9 Mg C ha−1for Mtimbwani. Soil carbon contributed over 65% of these stocks, decreasing with depth. Mid zones of the mangrove stands had highest carbon stocks. These data demonstrate that studied mangroves are potential for carbon projects and provide the baseline for monitoring, reporting, and verification (MRV) to support the projects.

Highlights

Mangrove forests occur in fragmented stands along almost the entire coastline of Tanzania mainland
We report on results of the inventory in the mangrove forests of Geza and Mtimbwani villages in the north-eastern region of Tanga, Tanzania, that aimed to (i) characterise the tree composition and structure; (ii) estimate the carbon stocks; and (iii) demonstrate the potential for community based carbon market schemes
Based on their importance values (IV), R. mucronata was the principal species in Geza and A. marina in Mtimbwani

Summary

Introduction

Mangrove forests occur in fragmented stands along almost the entire coastline of Tanzania mainland. Mangroves are reported to be up to five times efficient carbon sinks compared to other forms of terrestrial forests [7,8,9]. There exists large nonlinearity in ecosystem services provided by different mangrove formations [8, 10] that hinder generalised estimates of mangrove forest ecosystems’ carbon sequestration and stocks which is complicated by local conditions such as climate and soil factors; forest age, growth, and structure; utilisation and management regime of respective forests [3, 7, 11,12,13]. The reported high rate of mangrove carbon sequestration provides global benefits in mitigating the effects of climate change [9, 13, 14] and demonstrates potential for livelihood enhancement through community carbon market schemes for sustainable conservation [16, 17]

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Conclusion