Standing Biomass and Litter-Fall Dynamics in Reforested Mangroves of Douala-Edea National Park, Cameroon | InformativeBD

Laurant Nyamsi-Moussian , Gordon N. Ajonina , Guillaume L. Essomè-Koum , Ernest F. Kottè-Mapoko , Boubakary , Alphonse Konango-Samè , Vanessa M. Ngo-Massou, Jean M. Emanè , and Ndongo Din, from the different institute of the Cameroon. wrote a research article about, Standing Biomass and Litter-Fall Dynamics in Reforested Mangroves of Douala-Edea National Park, Cameroon. entitled, Assessment of standing biomass and litter-fall production in reforested mangrove stands within Douala-Edea National Park (Cameroon). This research paper published by the Journal of Biodiversity and Environmental Sciences (JBES). an open access scholarly research journal on Biodiversity. under the affiliation of the International Network For Natural Sciences | INNSpub. an open access multidisciplinary research journal publisher.

Abstract

Ecological restoration is considered like the practical and sustainable management option for degraded mangroves. The ecological status of reforested mangrove areas (RMAs) in Douala-Edea National Park (DENP) is not well understood, despite extensive restoration projects. This study aims to estimate standing biomass and litterfall production in three RMAs located in Bolondo and Yoyo II. In each RMA and it natural vegetation, five 10m × 10m permanent sampling plots (PSPs) were established. Thirty PSPs were established equally in RMAs and natural vegetation. Height and diameter measurements were recorded, and allometric equations were used to estimate above-ground biomass (AGB) and below-ground biomass (BGB). In addition, 150 litter traps (1m × 1m) were evenly distributed across the PSPs to collect monthly litterfall, which was dried, sorted, and weighed. Mean abundances, diameters, and heights were: 4000±200 ind./ha, 1.2±0.5 cm, and 1.8±0.3 m; 3280±238.74 ind./ha, 2.58±0.85 cm, and 5.64±1.87 m; 2160±240.83 ind./ha, 2.93±1.4 cm, and 3.34±1.26 m for 3-year, 6-year and 11-year RMAs respectively. AGB, BGB, and annual litterfall biomass were: 11.98±0.76 kg/ha, 13.88±1.3 kg/ha, and 40.78±7.42 g/m²/year for 3-year RMAs; 61.18±2.16 kg/ha, 55.19±1.92 kg/ha, and 397.75±75.79 g/m²/year for 6-year RMAs; and 55.25±2.93 kg/ha, 47.8±1.31 kg/ha, and 576.23±106.75 g/m²/year for 11-year RMAs, respectively. These values correspond 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. Although 6-year RMAs showed higher AGB and BGB than natural vegetation, the values remained lower overall. In contrast, 11-year RMAs exhibited higher annual litterfall production, indicating progress towards ecological balance.

Read more : Impact of Soil pH on Germination of Gmelina arborea Genetic Resources | InformativeBD

Introduction

Globally, mangroves cover an area of 137,000 km² (Spalding and Leal, 2021). These tropical coastal forest ecosystems are renowned for their high biomass productivity and carbon sequestration capacity (Alongi, 2011; Chowdhury et al., 2023). On average, a minimally disturbed mangrove sequesters 1087±584 MgC/ha (Sasmito et al., 2020). The conservation of mangroves is crucial for the wellbeing of local human communities and the fight against global warming (Din et al., 2016; Kathiresan et al., 2021).

However, mangroves are under threat from both natural and human-induced pressures, leading to a reduction in vegetation cover (Golberg et al., 2020; Emanè et al., 2021). Between 1996 and 2016, the rate of deforestation of mangroves was estimated at 4.3 % (Spalding and Leal, 2021). During the period of 2000- 2012, almost 1646 km² of the world's mangrove area disappeared. Along its western Atlantic coast, Cameroon has 1113 km² of mangroves (Hamilton and Casey, 2016). Over the last two decades, these mangroves have been subject to increased anthropisation, which has led to a considerable decrease in vegetation cover (Din et al., 2017). The mangroves in Douala-Edea National Park (DENP) are also affected by this issue. According to Ajonina and Usongo (2001), the annual regression rate of these mangroves was estimated to be 53 ha before 2000. Similarly, Findi and Wantim (2022) observed a regression rate of 58.38 % between 2011 and 2015 using satellite image analysis. For at least three decades, these mangroves have been the primary source of firewood used for smoking fish in various fishing camps and surrounding households (Ajonina, 2008).

In response to this ecological disaster, various options for mangrove conservation have been implemented worldwide, including restoration. Mangrove restoration refers to a set of human actions aimed at re-establishing ecological processes that accelerate the recovery of forest structure, ecological functioning, and biodiversity to levels typical of climax forest (Elliott et al., 2013). According to Worthington and Spalding (2018), over 190,147 km² of mangroves were restored globally by 2018. In Central Africa, Ajonina et al. (2016) reported that over 500 ha of degraded mangroves were reforested before 2017. Reforestation of degraded mangroves in Cameroon officially began in 2009 and continues to this day. In 2023, Planète-Urgence’s NGO implemented the planting of 40,000 seedlings in the mangroves of Bolondo fishing camp village located in DENP, with the involvement of governmental organizations and other partners (Planète-Urgence, 2023).

Mangrove restoration projects face numerous obstacles worldwide, often resulting in partial or complete failure (López-Portillo et al., 2017; Worthington and Spalding, 2018; Ellison et al., 2020; Lhosupasirirat et al., 2023). These failures not only cause ecological damage but also result in significant financial losses, with the average cost of restoring one hectare in Central Africa estimated at US$ 3200 (Ajonina et al., 2016). Lee et al. (2019) identified the absence of a comprehensive database for monitoring and assessment restoration projects as a major obstacle to mangrove restoration efforts.

There is a lack of information on the structure and functioning of restored mangrove areas along the African Atlantic coast (Zabbey and Tanee, 2016). To our knowledge, in Cameroon, there is only one specific study on mangrove restoration which is limited to determining the main abiotic factors that influence the growth of seedlings in nurseries (Boubakary et al., 2019). No published scientific study has yet been conducted on the monitoring and assessment of standing biomass and litterfall production of reforested mangrove areas in the DENP. However, quantifying the biomass of reforested areas would be crucial for safeguarding mangroves in the DENP and for improving climate change mitigation strategies (Malik et al., 2020). Furthermore, it is essential to incorporate the monitoring of objectively verifiable indicators of ecosystem functioning, such as litterfall production Globally, mangroves cover an area of 137,000 km² (Spalding and Leal, 2021). These tropical coastal forest ecosystems are renowned for their high biomass productivity and carbon sequestration capacity (Alongi, 2011; Chowdhury et al., 2023). On average, a minimally disturbed mangrove sequesters 1087±584 MgC/ha (Sasmito et al., 2020). The conservation of mangroves is crucial for the wellbeing of local human communities and the fight against global warming (Din et al., 2016; Kathiresan et al., 2021). However, mangroves are under threat from both natural and human-induced pressures, leading to a reduction in vegetation cover (Golberg et al., 2020; Emanè et al., 2021). Between 1996 and 2016, the rate of deforestation of mangroves was estimated at 4.3 % (Spalding and Leal, 2021). During the period of 2000- 2012, almost 1646 km² of the world's mangrove area disappeared. Along its western Atlantic coast, Cameroon has 1113 km² of mangroves (Hamilton and Casey, 2016). Over the last two decades, these mangroves have been subject to increased anthropisation, which has led to a considerable decrease in vegetation cover (Din et al., 2017). The mangroves in Douala-Edea National Park (DENP) are also affected by this issue. According to Ajonina and Usongo (2001), the annual regression rate of these mangroves was estimated to be 53 ha before 2000. Similarly, Findi and Wantim (2022) observed a regression rate of 58.38 % between 2011 and 2015 using satellite image analysis. For at least three decades, these mangroves have been the primary source of firewood used for smoking fish in various fishing camps and surrounding households (Ajonina, 2008). In response to this ecological disaster, various options for mangrove conservation have been implemented worldwide, including restoration. Mangrove restoration refers to a set of human actions aimed at re-establishing ecological processes that accelerate the recovery of forest structure, ecological functioning, and biodiversity to levels typical of climax forest (Elliott et al., 2013). According to Worthington and Spalding (2018), over 190,147 km² of mangroves were restored globally by 2018. In Central Africa, Ajonina et al. (2016) reported that over 500 ha of degraded mangroves were reforested before 2017. Reforestation of degraded mangroves in Cameroon officially began in 2009 and continues to this day. In 2023, Planète-Urgence’s NGO implemented the planting of 40,000 seedlings in the mangroves of Bolondo fishing camp village located in DENP, with the involvement of governmental organizations and other partners (Planète-Urgence, 2023). Mangrove restoration projects face numerous obstacles worldwide, often resulting in partial or complete failure (López-Portillo et al., 2017; Worthington and Spalding, 2018; Ellison et al., 2020; Lhosupasirirat et al., 2023). These failures not only cause ecological damage but also result in significant financial losses, with the average cost of restoring one hectare in Central Africa estimated at US$ 3200 (Ajonina et al., 2016). Lee et al. (2019) identified the absence of a comprehensive database for monitoring and assessment restoration projects as a major obstacle to mangrove restoration efforts. There is a lack of information on the structure and functioning of restored mangrove areas along the African Atlantic coast (Zabbey and Tanee, 2016). To our knowledge, in Cameroon, there is only one specific study on mangrove restoration which is limited to determining the main abiotic factors that influence the growth of seedlings in nurseries (Boubakary et al., 2019). No published scientific study has yet been conducted on the monitoring and assessment of standing biomass and litterfall production of reforested mangrove areas in the DENP. However, quantifying the biomass of reforested areas would be crucial for safeguarding mangroves in the DENP and for improving climate change mitigation strategies (Malik et al., 2020). Furthermore, it is essential to incorporate the monitoring of objectively verifiable indicators of ecosystem functioning, such as litterfall production

Reference

Ajonina GN, Usongo L. 2001. Preliminary Quantitative Impact Assessment of Wood Extraction on the Mangroves of Douala-Edea Forest Reserve, Cameroon. Tropical Biodiversity 7, 137–149. https://www.researchgate.net/publication/313056745

Ajonina GN. 2008. Inventory and Modelling Mangrove Forest Stand Dynamics Following Different Levels of Wood Exploitation Pressures in the Douala-Edea Atlantic Coast of Cameroon, Central Africa. PhD thesis, Albert-Ludwigs-Universität, Germany, 215.

Ajonina G, Chuyong G. 2011. Vulnerability assessment of mangrove forest stands from anthropogenic wood exploitation pressures and sea level rise impacts following a re-census survey and analysis of eight years old permanent sample plots in the Douala-Edea Estuary, Cameroon. Technical Report, 1-27. http://doi.org/10.13140/RG.2.2.36502.24644

Ajonina GN, Aya FA, Diame A, Armah AK, Camara S, Amegankpoe C, Zabbey N, Kaya P. 2016. Overview of Experience of Mangrove Reforestation in West and Central Africa. In Ogunsanwo OY, Akinwole AO, eds., 38th Annual Conference of FAN. Forestry Association of Nigeria 17, 12-21. https://www.researchgate.net/publication/314243276

Alongi DM. 2011. Carbon Payments for Mangrove Conservation: Ecosystem Constraints and Uncertainties of Sequestration Potential. Environmental Sciences Policy 14, 462–470. https://doi.org/10.1016/j.envsci.2011.02.004

Bosire JO, Dahdouh-Guebas F, Walton M, Crona BI, Lewis RR, Field CD, Kairo JG, Koedam N. 2008. Functionality of Restored Mangroves: A review. Aquatic Botany 89, 251–259. https://doi.org/10.1016/j.aquabot.2008.03.010

Bosire JO, Kairo JG, Wartel S, Kazungu J, Koedam N. 2006. Success Rates of Recruited Tree Species and their Contribution to the Structural Development of Reforested Mangrove Stands. Marine Ecology Progress Series 325, 85–91. https://doi.org/10.3354/meps325085

Boubakary, Essomè-Koum, GL, Nyamsi-Moussian L, Konango-Samè A, Kottè-Mapoko EF, Motto IS, Massako F, Din N. 2019. Mangrove Ecosystems Rehabilitation in Cameroon: Effects of Two Abiotic Factors on the Growth of Rhizophora Seedlings. Journal of Marine Biology and Environmental Sciences 1, 1–6. https://doi.org/https://doi.org/10.36266/JMBES/101

Chowdhury A, Naz A, Maiti SK. 2023. Variations in Soil Blue Carbon Sequestration between Natural Mangrove Metapopulations and a Mixed Mangrove Plantation: A Case Study from the World’s Largest Contiguous Mangrove Forest. Life 13, 1-11. https://doi.org/10.3390/life13020271

Dahdouh-Guebas F, Cannicci S. 2021. Mangrove Restoration Under Shifted Baselines and Future Uncertainty. Frontier in Marine Science 8, 8-11. https://doi.org/10.3389/fmars.2021.799543

Din N, Ngo-Massou VM, Essomè-Koum GL, Ndema-Nsombo E, Kottè-Mapoko E, Nyamsi-Moussian L. 2017. Impact of Urbanization on the Evolution of Mangrove Ecosystems in the Wouri River Estuary (Douala Cameroon). In Finkl CW, Makowski C Ed. Coastal Wetlands : Alteration and Remediation. Coastal Research Library, Springer 8, 81–131. https://doi.org/10.1007/978-3-319-56179-0

Din N, Ngo-Massou VM, Essomè-Koum GL, Kottè-Mapoko EF, Emane JM, Akongnwi AD, Tchoffo R. 2016. Local Perception of Climate Change and Adaptation in Mangrove Areas of the Cameroon Coast. Journal of Water Resource and Protection, 608–618.

Elliott S, Blakesley D, Hardwick K. 2013. Restauration des Forêts Tropicales: un guide pratique. Sonne N Ed. Royal Botanic Garden, Kew, 344. https://www.forru.org/sites/default/files/public/publications/resources/forru-0000152-0003.pdf

Ellison AM, Felson AJ, Friess DA. 2020. Mangrove Rehabilitation and Restoration as Experimental Adaptive Management. Frontier in Marine Science 7, 1–19. https://doi.org/10.3389/fmars.2020.00327

Emanè JM, Essomè-Koum GL, Ngotta-Biyon J, Ekodeck, GE, Tomedi-Eyango M, Din N. 2021. Effects of Anthropogenic Pressures on the Structure of Floristic Components of Mangroves in the Cameroon Estuary. Examines in Marine Biology and Oceanography 4, 1–7. https://doi.org/10.31031/EIMBO.2021.04.00057

Ferreira AC, Ganade G, Jose Luiz de Attayde. 2015. Restoration Versus Natural Regeneration in a Neotropical Mangrove : Effects on Plant Biomass and Crab Communities. Ocean and Coastal Management Journal 110, 2002-2009. https://doi.org/10.1016/j.ocecoaman.2015.03.006

Findi EN, Wantim MN. 2022. Using Remote Sensing and GIS to Evaluate Mangrove Forest Dynamics in Douala-Edea Reserve, Cameroon. Journal of Materials and Environmental Science 13, 222–235.

Fromard F, Puig H, Mougin E, Marty G, Betoulle JL, Cadamuro L. 1998. Structure, Above-Ground Biomass and Dynamics of Mangrove Ecosystems: New Data from French Guiana. Oecologia 115, 39-53.

Goldberg L, Lagomasino, D, Thomas, N. 2020. Global Declines in Human‐driven Mangrove Loss. Global Change Biology. 26, 1-32. https://doi.org/10.1111/gcb.15275

Hamilton SE, Casey D. 2016. Creation of a High Spatio-Temporal Resolution Global Database of Continuous Mangrove Forest Cover for the 21st Century (CGMFC-21). Global Ecology Biogeography 25, 729-738. https://doi.org/10.1111/geb.12449

Hieu PV, Dung LP, Tue NT, Omori K. 2017. Will Restored Mangrove Forests Enhance Sediment Organic Carbon and Ecosystem Carbon Storage. Regional Studies in Marine Science https://doi.org/10.1016/j.rsma.2017.05.003

Kairo JG, Lang’at JKS, Dahdouh-Guebas F, Bosire JO, Karachi M. 2008. Structural Development and Productivity of Replanted Mangrove Plantations in Kenya. Forest Ecology and Management 255, 2670-2677. https://doi.org/10.1016/j.foreco.2008.01.031

Kamruzzaman M, Osawa A, Deshar R, Sharma S, Mouctar K. 2017. Species Composition, Biomass, and Net Primary Productivity of Mangrove Forest in Okukubi River, Okinawa Island, Japan. Regional Studies in Marine Science 12, 19-27. https://doi.org/10.1016/j.rsma.2017.03.004

Kamruzzaman M, Kalayan B, Sumonta PK, Ahmed S, Osawa A. 2019. Litterfall Production, Decomposition and Nutrient Accumulation in Sundarbans Mangrove Forests, Bangladesh. Forest Science and Technology, 1-9. https://doi.org/10.1080/21580103.2018.1557566

Kathiresan K. 2021. Mangroves: Types and Importance. In Rastogi RP, Gupta DK, Phulwaria M, Ed. Mangroves: Ecology, Biodiversity and Manegement, Springer, 1-31. https://doi.org/10.1007/978-981-16-2494-0

Kauffman JB, Donato DC. 2012. Protocols for the Measurement, Monitoring and Reporting of Structure, Biomass and Carbon Stocks in Mangrove Forests. Working Paper 86. CIFOR, Bogor, Indonesia, 1-40. www.cifor.org

Komiyama A, Jin O, Poungparn S. 2008. Allometry, Biomass and Productivity of Mangrove Forests : A Review. Aquatic Botany 2094, 1-10. https://doi.org/10.1016/j.aquabot.2007.12.006

Lee SY, Hamilton S, Barbier EB, Primavera J, Lewis RR. 2019. Better Restoration Policies Are Needed to Conserve Mangrove Ecosystems. Nature Ecology and Evolution 3, 870-872. https://doi.org/10.1038/s41559-019-0861-y

Lhosupasirirat P, Dahdouh-Guebas F, Hugé J, Wodehouse D, Enright J. 2023. Young Voices and Visions for the Stakeholder Perceptions on Community-Based Ecological Mangrove Restoration (CBEMR): a Case Study in Thailand. Society for Ecological Restoration 31, 1–14. https://doi.org/10.1111/rec.13894

López-Portillo J, Lewis RRI, Shing VHR, Lee Y. 2017. Mangrove Ecosystems : A Global Biogeographic Perspective Structure, Function, and Services. In Rivera-Monroy VH, Lee SY, Kristensen E, Twilley RR Ed. Mangrove Ecosystems: A Global Biogeographic Perspective: Structure, Function, and Services, 301–345. https://doi.org/10.1007/978-3-319-62206-4

Malik A, Jalil AR, Arifuddin A, Syahmuddin A. 2020. Biomass Carbon Stocks in the Mangrove Rehabilitated Area of Sinjai District, South Sulawesi, Indonesia. Geography, Environment, Sustainability 2012, 32–38. https://DOI-10.24057/2071-9388-2019-131

Mchenga ISS, Ali AI. 2017. Mangrove Litter Production and Seasonality of Dominant Species in Zanzibar, Tanzania. Journal of East African Natural History 106, 5-18. https://doi.org/https://www.ajol.info/index.php/jeanh/article/view/162370/151879

Monga E, Mangora MM, Trettin CC. 2022. Impact of Mangrove Planting on Forest Biomass Carbon and other Structural Attributes in the Rufiji Delta, Tanzania. Global Ecology and Conservation 35, 1-12. https://doi.org/10.1016/j.gecco.2022.e02100

Ngo-Massou VM, Kenne M, Dongmo AB. 2016. Effect of Anthropogenic Activities on Mangrove Crab Diversity in Cameroon Atlantic Coast. International Journal of Research Studies in Biosciences 4, 1-12. http://dx.doi.org/10.20431/2349-0365.0404001

Ntyam OCS, Armah AK, Ajonina GN, Wiafe G, Adomako J, Nyarko E, Obiang BO. 2014. Importance of Mangrove Litter Production in the Protection of Atlantic Coastal Forest of Cameroon and Ghana. In The Land/Ocean Interactions in the Coastal Zone of West and Central Africa, Estuaries of the World, Diop S, Barusseau JP, Descamps C. Ed. Springer International, 123-137. https://doi.org/10.1007/978-3-319-06388-1

Planète-Urgence. 2023. Projet Cameroon Mangrove Ecosystem Restoration and Resilience. Web page available by: https://planete-urgence.org/en/projet-camerr-cameroon-mangrove-ecosystem-restoration-and-resilience/

Pradisty NA, Sidik F, Bimantara Y, Susetya IE, Basyuni M. 2022. Litterfall and Associated Macrozoobenthic of Restored Mangrove Forests in Abandoned Aquaculture Ponds. Sustainability 14, 2-19. https://doi.org/10.3390/su14138082

Sasmito SD, Sillanpää M, Hayes MA, Bachri S, Saragi-Sasmito MF, Sidik F, Hanggara B, Mofu WY, Rumbiak VIR, Hendri, Taberima S, Suhaemi, Nugroho JD, Pattiasina TF, Widagti N, Barakalla, Rahajoe JS, Hartantri H, Nikijuluw V, Jowey RN, Heatubun CD, Ermgassen P, Worthington T, Howard J, Lovelock CE, Friess DA, Hutley LB, Murdiyarso D. 2020. Mangrove Blue Carbon Stocks and Dynamics are Controlled by Hydrogeomorphic Settings and Land-Use Change. Global Change Biology, 1-6. https://doi.org/10.1111/gcb.15056

Spalding M, Leal M. 2021. The State of the World’s Mangroves 2021 (M. Spalding and M. Leal Ed. Global Mangrove Alliance. https://doi.org/www.mangrovealliance.org

Wang’ondu VW, Bosire JO, Kairo JG, Kinyamario JI, Mwaura FB, Dahdouh-Guebas F, Koedam N. 2014. Litterfall Dynamics of Restored Mangroves (Rhizophora mucronata Lamk. and Sonneratia alba Sm.) in Kenya. Restoration Ecology 22, 824–831. https://doi.org/10.1111/rec.12149

Worthington T, Spalding M. 2018. Mangrove Restoration Potential: A Global Map Highlighting a Critical Opportunity (UICN (ed.)). UICN, University of Cambridge, The Nature Conservancy, 1-34. https://doi.org/10.17863 /CAM.39153

Zabbey N, Tanee FBG. 2016. Assessment of Asymmetric Mangrove Restoration Trials in Ogoniland, Niger Delta, Nigeria: Lessons for Future Intervention, 245–257.

Source : Assessment of standing biomass and litter-fall production in reforested mangrove stands within Douala-Edea National Park (Cameroon)