Organic Carbon Stocks in all Pools Following Land Cover Change in the Rainforest of Madagascar

Razafindrakoto, Mieja; Andriamananjara, Andry; Razafimbelo, Tantely; Hewson, Jenny; Andrisoa, Riana H.; Jones, Julia P. G.; Meerveld, Ilja van; Cameron, A.; Ranaivoson, Ntsoa; Ramifehiarivo, Nandrianina; Ramboatiana, Nantenaina; Razafinarivo, Ravo N.G.; Ramananantoandro, Tahiana; Rasolohery, Andriambolantsoa; Razafimanantsoa, Marie P.; Jourdan, Christophe; Saint‐André, Laurent; Rajoelison, Gabrielle; Razakamanarivo, Herintsitohaina

doi:10.1016/b978-0-12-812128-3.00003-3

Cited by 3 publications

(3 citation statements)

References 22 publications

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“…Similar observations were reported by several authors in landscapes where forest vegetation had been transformed into grassland more than a 1000 years ago, showing evidence that C 3 -derived carbon can remain present for millennia after the replacement of the original vegetation (Desjardins et al, 2013;Guillet et al, 2001;Schwartz et al, 1986). Rabetokotany-Rarivoson et al (2015) and Razafindrakoto et al (2018) found a strong difference in SOC stocks between the initial forest vegetation and the final stage of deforestation (i.e. a landscape dominated by grasses).…”

Section: Response Of Soc Stocks To Vegetation Transitionsupporting

confidence: 84%

Stable isotope profiles of soil organic carbon in forested and grassland landscapes in the Lake Alaotra basin (Madagascar): insights in past vegetation changes

Razanamahandry

Dewaele²,

Govers³

et al. 2022

Biogeosciences

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Abstract. The extent to which the central highlands of Madagascar were once covered by forests is still a matter of debate: while reconstructing past environments is inherently difficult, the debate is further hampered by the fact that the evidence documenting land cover changes and their effects on carbon and sediment dynamics in Madagascar has hitherto mainly been derived from lake coring studies. Such studies provide an integrated view over relatively large areas but do not provide information on how land-use change affects hillslopes in terms of carbon and sediment dynamics. Such information would not only be complementary to lake inventories but may also help to correctly interpret lake sediment data. Carbon stable isotope ratios (δ13C) are particularly useful tracers to study the past dynamics of soil carbon over time spans ranging from years to millennia and thus to understand the consequences of land-use change over such time spans. We analysed soil profiles down to a depth of 2 m from pristine forests and grasslands in the Lake Alaotra region in central Madagascar. Along grassland hillslopes, soil organic carbon (SOC) content was low, from 0.4 % to 1.7 % in the top layer, and decreased rapidly to ca. 0.2 % below 100 cm depth. The current vegetation predominantly consists of C4 grasses (δ13C ∼ −13 ‰), yet topsoil δ13C-OC ranges between −23.0 ‰ and −15.8 ‰, and most profiles show a decrease in δ13C-OC with depth. This contrasts with our observations in the C3-dominated forest profiles, which show a typical profile whereby δ13C values increase slightly with depth. Moreover, the SOC stock of grasslands was ∼ 55.6 % lower than along the forested hillslopes for the upper 0–30 cm layer. δ13C values in grassland and forest profiles converge to similar values (within 2.0 ± 1.8 ‰) at depths below ∼ 80 cm, suggesting that the grasslands in the Lake Alaotra region have indeed developed on soils formerly covered by a tree vegetation dominated by C3 plants. We also observed that the percent of modern carbon (pMC) of the bulk OC in the top, middle and lower middle positions of grasslands was less than 85 % near the surface. This could reflect a combination of (i) the long residence time of forest OC in the soil, (ii) the slow replacement rate of grassland-derived OC (iii) and the substantial erosion of the top positions towards the valley position of grasslands. At the valley positions under grassland, the upper 80 cm contains higher amounts of recent grass-derived OC in comparison to the hillslope positions. This is likely to be related to the higher productivity of the grassland valleys (due to higher moisture and nutrient availability), and the deposition of OC that was eroded further upslope may also have contributed. The method we applied, which is based on the large difference in δ13C values between the two major photosynthetic pathways (C3 and C4) in (sub-)tropical terrestrial environments, provides a relatively straightforward approach to quantitatively determine changing vegetation cover, and we advocate for its broader application across Madagascar to better understand the island's vegetation history.

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Section: Response Of Soc Stocks To Vegetation Transitionsupporting

confidence: 84%

Stable isotope profiles of soil organic carbon in forested and grassland landscapes in the Lake Alaotra basin (Madagascar): insights in past vegetation changes

Razanamahandry

Dewaele²,

Govers³

et al. 2022

Biogeosciences

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“…A particular problem is tendency to use above ground biomass as the main indicator of carbon stocks, which can lead to the underestimation of carbon stored in open and mosaic ecosystems. In Madagascar, as elsewhere, soil carbon pools hold three times higher than above-ground (Powers et al, 2011;Grinand et al, 2017;Ramifehiarivo et al, 2017;Dass et al, 2018;Razafindrakoto et al, 2018;Veldman et al, 2019;Yang et al, 2019).…”

Section: Balancing Trade-offs Between Biodiversity Carbon Storage a R...mentioning

confidence: 65%

“…Furthermore, the benefits of tree-planting risks being overestimated if only above-ground biomass is considered, as most carbon is below ground (e.g. see Dass et al, 2018;Razafindrakoto et al, 2018;Veldman et al, 2019). In recent years, guidelines have emerged that advocate more ecologically sound and socially inclusive approaches to tree-planting, and that consider ecological relevance, drivers of forest loss, and social dimensions (e.g.…”

Section: Introductionmentioning

confidence: 99%

The role of palaeoecology in reconciling biodiversity conservation, livelihoods and carbon storage in Madagascar

Gillson,

Razanatsoa,

Razafimanantsoa

et al. 2023

Front. Conserv. Sci.

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Planting trees is proposed as an important climate mitigation tool, but can be detrimental to biodiversity and livelihoods if not carefully planned and managed, with landscape history and livelihoods in mind. In Madagascar, deforestation is of concern, and a threat to forest-adapted biota. However, much of Madagascar’s landscape harbours ancient mosaic and open ecosystems that are home to unique suites of flora and fauna and provide a wide range of ecosystem services. Though guidelines for ecologically and socially responsible reforestation are emerging, the potential role of landscape history and palaeoecology has been generally underemphasised. Here, using Madagascar as a case study, we argue that forest restoration projects need a sound understanding of landscape history that includes a greater integration of palaeoecological data. This would help establish the former composition and extent of forests and also investigate the antiquity of open and mosaic ecosystems. When economic interests are strong, information from palaeoecology and environmental history can help reduce biases when identifying appropriate locations and suites of species for forestation. Furthermore, a reflective approach to landscape history can contribute to restoration projects that integrate cultural and livelihood considerations. A transdisciplinary approach that considers local needs and cultural context can facilitate the design and implementation of restoration projects that share benefits equitably. Underpinning this ambition is a more comprehensive consideration of ecosystem service benefits in a changing climate that includes accurate carbon storage calculations, as well as other ecosystem services including water provision, soil formation and erosion prevention, grazing resources, medicine and cultural components.

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Dynamics of land use land cover and its impact on carbon stocks in Sub-Saharan Africa: an overview

Olorunfemi

Olufayo

Fasinmirin

et al. 2021

Environ Dev Sustain

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Organic Carbon Stocks in all Pools Following Land Cover Change in the Rainforest of Madagascar

Cited by 3 publications

References 22 publications

Stable isotope profiles of soil organic carbon in forested and grassland landscapes in the Lake Alaotra basin (Madagascar): insights in past vegetation changes

Stable isotope profiles of soil organic carbon in forested and grassland landscapes in the Lake Alaotra basin (Madagascar): insights in past vegetation changes

The role of palaeoecology in reconciling biodiversity conservation, livelihoods and carbon storage in Madagascar

Dynamics of land use land cover and its impact on carbon stocks in Sub-Saharan Africa: an overview

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