Tracking land-cover changes with sedimentary charcoal in the Afrotropics

Aleman Julie, Blarquez Olivier, Bentaleb Ilham, Bonté Philippe, Brossier Benoit, Carcaillet Christopher, Gond Valéry, Gourlet-Fleury Sylvie, Kpolita Arnot, Lefèvre Irène, Oslisly Richard, Power Mitchell J., Yongo Olga Diane, Bremond Laurent, Favier Charly. 2013. Tracking land-cover changes with sedimentary charcoal in the Afrotropics. Holocene, 23 (12) : 1853-1862.

Quartile : Q1, Sujet : GEOSCIENCES, MULTIDISCIPLINARY / Quartile : Q1, Sujet : GEOGRAPHY, PHYSICAL

Liste HCERES des revues (en SHS) : oui

Thème(s) HCERES des revues (en SHS) : Géographie-Aménagement-Urbanisme-Architecture; Histoire, histoire de l'art, archéologie

Résumé : Fires have played an important role in creating and maintaining savannas over the centuries and are also one of the main natural disturbances in forests. The functional role of fires in savannas and forests can be investigated through examining sedimentary charcoal in order to reconstruct long-term fire history. However, the relationship between charcoal and vegetation structure in tropical grassy ecosystems remains to be elucidated. Here, we compared recent charcoal records from lake sediments in three tropical ecosystems (forest, savanna, and forest-savanna mosaic) with land cover inferred from remote-sensing images. Charcoal width-to-length (W/L) ratio is a good proxy for changes in fuel type. At one of the lakes, a significant W/L modification from values >0.5 (mainly wood) to <0.5 (¿grass) was recorded simultaneously with changes in land cover. Indeed, a significant deforestation was recorded around this lake in the remote-sensing imagery between 1984 and 1994. The results also indicate that a riparian forest around a lake could act as a physical filter for charcoal accumulation; we used the mean charcoal size as a proxy to evaluate this process. Charcoal Accumulation Rates (CHAR), a burned biomass proxy, were combined with W/L ratio and the mean charcoal size to investigate the land-use history of the landscapes surrounding the study sites. This combined approach allowed us to distinguish between episodic slash-and-burn practices in the forest and managed fields or pastures burning frequently.

Mots-clés Agrovoc : savane, forêt tropicale, incendie spontané, incendie de forêt, végétation, utilisation des terres, aménagement forestier, télédétection, charbon de bois, écosystème, paysage, sédiment, filtration

Classification Agris : K01 - Foresterie - Considérations générales
F40 - Écologie végétale
000 - Autres thèmes

Champ stratégique Cirad : Axe 6 (2005-2013) - Agriculture, environnement, nature et sociétés

Auteurs et affiliations

• Aleman Julie, CNRS (FRA)
• Blarquez Olivier, UQAM (CAN)
• Bentaleb Ilham, UM2 (FRA)
• Bonté Philippe, CEA (FRA)
• Brossier Benoit, CNRS (FRA)
• Carcaillet Christopher, EPHE (FRA)
• Gond Valéry, CIRAD-ES-UPR BSef (FRA) ORCID: 0000-0002-0080-3140
• Gourlet-Fleury Sylvie, CIRAD-ES-UPR BSef (FRA) ORCID: 0000-0002-1136-4307
• Kpolita Arnot, Université de Bangui (CAF)
• Lefèvre Irène, CEA (FRA)
• Oslisly Richard, IRD (GAB)
• Power Mitchell J., Utah State University (USA)
• Yongo Olga Diane, Université de Bangui (CAF)
• Bremond Laurent, EPHE (FRA)
• Favier Charly, CNRS (FRA)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/571479/)

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