Abstract
Mangrove ecosystems help mitigate climate change, are highly biodiverse, and provide critical goods and services to coastal communities. Despite their importance, anthropogenic activities are rapidly degrading and deforesting mangroves world-wide. Madagascar contains 2% of the world’s mangroves, many of which have undergone or are starting to exhibit signs of widespread degradation and deforestation. Remotely sensed data can be used to quantify mangrove loss and characterize remaining distributions, providing detailed, accurate, timely and updateable information. We use USGS maps produced from Landsat data to calculate nation-wide dynamics for Madagascar’s mangroves from 1990 to 2010, and examine change more closely by partitioning the national distribution in to primary (i.e., >1000 ha) ecosystems; with focus on four Areas of Interest (AOIs): Ambaro-Ambanja Bays (AAB), Mahajamba Bay (MHJ), Tsiribihina Manombolo Delta (TMD) and Bay des Assassins (BdA). Results indicate a nation–wide net-loss of 21% (i.e., 57,359 ha) from 1990 to 2010, with dynamics varying considerably among primary mangrove ecosystems. Given the limitations of national-level maps for certain localized applications (e.g., carbon stock inventories), building on two previous studies for AAB and MHJ, we employ Landsat data to produce detailed, contemporary mangrove maps for TMD and BdA. These contemporary, AOI-specific maps provide improved detail and accuracy over the USGS national-level maps, and are being applied to conservation and restoration initiatives through the Blue Ventures’ Blue Forests programme and WWF Madagascar West Indian Ocean Programme Office’s work in the region.
Highlights
Given the limitations of national-level maps for certain localized applications, and the limitations of existing and/or lack of ecosystem-specific maps for Areas of Interest (AOIs), we build on two previous studies for Ambanja Bays (AAB) and Mahajamba Bay (MHJ) [25,61] and employ Landsat data to produce detailed, contemporary, maps of Tsiribihina and Manambolo Deltas (TMD) and Baie des Assassins (BdA)
At the time of writing, detailed contemporary maps existed for no other specific mangrove ecosystems in Madagascar; highlighting the need to produce new maps for TMD and BdA to complement those produced for AAB and MHJ
In accordance with the approach described in Jones et al [25] for AAB, and Jones et al [61] for MHJ, to ensure the representativeness of and refine mangrove type and surrounding land-cover categories for TMD and BdA maps, preliminary field surveys were conducted in all four AOIs
Summary
Found in over 120 countries and territories between 30 ̋ N and 30 ̋ S latitude, mangrove ecosystems support high floral and faunal biodiversity and provide a diverse range of goods New techniques which go beyond single-date mapping and multi-date change detection are needed to create evolutionary models of mangroves; pushing the boundaries of Landsat-like remotely sensed data [66]. Mahajamba Bay (MHJ), and Mangoky Delta) (i.e., [73,74,75,76,77]) These maps are either out-of-date or lack the thematic detail required for certain management initiatives (e.g., carbon stock inventories); and for many of Madagascar’s mangrove ecosystems, are non-existent. Given the limitations of national-level maps for certain localized applications, and the limitations of existing and/or lack of ecosystem-specific maps for AOIs, we build on two previous studies for AAB and MHJ [25,61] and employ Landsat data to produce detailed, contemporary, maps of TMD and BdA
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
