Relative importance of local and regional/global drivers of mangrove degradation and deforestation in Madagascar

• Published in: Regional environmental change 2024-06, Vol.24 (2), p.84-84, Article 84
• Main Authors: Ramarokoto, Sitrakiniaina, Raharijaona, Léa J. R., Ravonjimalala, Rijasoa H., Randriamalala, Josoa R.
• Format: Article
• Language: English
• Subjects: Algorithms; biomass; Charcoal; Classification; Climate Change; Climate Change/Climate Change Impacts; Coastal erosion; Deep sea; Deforestation; Degradation; Earth and Environmental Science; Ecosystems; Environment; Fish; Fishery products; fuelwood; Geography; Landsat; Landsat satellites; Local population; logging; Madagascar; Mangroves; Nature Conservation; Oceanography; Original Article; Populations; Regional development; Regional/Spatial Science; Remote sensing; Satellite imagery; sea level; Sea level rise; sediments; statistical analysis; Timber
• ISSN: 1436-3798; 1436-378X
• DOI: 10.1007/s10113-024-02247-y

Mangrove ecosystems provide a wide range of goods and services including timber, fuelwood and fish products, for the local population and nationwide. However, these ecosystems are undergoing significant degradation and deforestation because of local and regional/global drivers. Local drivers relate to mangrove use by local populations. Regional/global drivers include changes in abiotic parameters of mangroves due to sea level rise (global) and sedimentation (regional). The aim of this paper is to analyze the relative importance of these two sets of drivers, with a particular focus on mangroves in western Madagascar. We analyzed the spatiotemporal dynamics of mangroves in the study site over the last 30 years by processing four Landsat satellite images (1990/2000/2010/2020) using a supervised classification method with the maximum likelihood classification algorithm. Transition matrices have been developed between the years 1990 and 2020 to identify the causes of mangrove degradation and deforestation. An annual loss of 0.38% was recorded during this period of time. This loss is primarily the result of local drivers such as charcoal production and timber extraction (85% loss over the last 30 years vs 15% of losses attributed to regional/global drivers). Excess sediment input and coastal erosion are the regional/global drivers of mangrove degradation and deforestation. Developing deep-sea fishing is the main way to sustainably manage mangrove wood resources and reduce the dependence of local populations on them. Future research should analyze the effects of mangrove degradation and deforestation on the diversity and biomass of fish in this ecosystem.