Rates and drivers of mangrove deforestation in Southeast Asia, 2000-2012
Year Published:
Study Number:
87
Author:

Daniel R. Richards and Danial A. Friess

Abstract:

The mangrove forests of Southeast Asia are highly biodiverse and provide multiple ecosystem services upon which millions of people depend. Mangroves enhance fisheries and coastal protection, and store among the highest densities of carbon of any ecosystem globally. Mangrove forests have experienced extensive deforestation owing to global demand for commodities, and previous studies have identified the expansion of aquaculture as largely responsible. The proportional conversion of mangroves to different land use types has not been systematically quantified across Southeast Asia, however, particularly in recent years. In this study we apply a combined geographic information system and remote sensing method to quantify the key proximate drivers (i.e., replacement land uses) of mangrove deforestation in Southeast Asia between 2000 and 2012. Mangrove forests were lost at an average rate of 0.18% per year, which is lower than previously published estimates. In total, more than 100,000 ha of mangroves were removed during the study period, with aquaculture accounting for 30% of this total forest change. The rapid expansion of rice agriculture in Myanmar, and the sustained conversion of mangroves to oil palm plantations in Malaysia and Indonesia, are identified as additional increasing and under-recognized threats to mangrove ecosystems. Our study highlights frontiers of mangrove deforestation in the border states of Myanmar, on Borneo, and in Indonesian Papua. To implement policies that conserve mangrove forests across Southeast Asia, it is essential to consider the national and subnational variation in the land uses that follow deforestation.

Main Results and Conclusions:
  • Southeast Asia is a key site for mangroves, with the greatest diversity of mangroves and over one-third of global mangrove forests. Land use and land cover change (LULCC) threatens mangroves in Southeast Asia, and has the potential to emit carbon equal to between 2 and 8% of emissions from all other deforestation.
    • “LULCC in mangroves may result in carbon emissions equal to 2-8% of emissions from terrestrial deforestation, despite the fact this ecosystem represents only 0.7% of the global tropical forest area (13, 14).” (344)
  • Extent of deforestation and LULCC in Southeast Asia: Mangroves were lost at a rate of .18% per year between 2000 and 2012 for a total of 100,000 hectares lost. These numbers are actually lower than previous estimates. Additionally, mangrove conservation and replenishment projects may help to reduce the rate at which mangroves are lost.
    •  “The rate of mangrove forest expansion is considerable in South Asia (6), so it is possible that the percentage net loss in mangrove forest area in Southeast Asia between 2000 and 2012 may be less than 2%.” (347)
  • Mangrove conversion to aquaculture is the main factor in mangrove loss. Many countries in Southeast Asia encourage this conversion in order to promote food security and boost economic productivity.
    •  “in 2012 Indonesia’s production (9.6 million tons) was almost three-fold larger than that of other regional aquaculture producers, such as Vietnam (3.3 million tons) (34). Indonesian government departments continue to encourage growth in the industry as a means of improving livelihood, generating foreign currency, and providing protein (30), so further mangrove conversion may be expected in the future.” (347)
  • Conversion of mangroves for rice production was responsible for over 20% of the total  change in mangrove forests in Southeast Asia. Myanmar, the country primarily promoting this conversion, has the fastest rate of mangrove deforestation in the region.
  • Palm oil production is another major factor driving mangrove deforestation, especially in Malaysia and Indonesia.
    • “The responsibility for intertidal habitats, such as mangroves, commonly falls between marine and terrestrial government agencies, which can lead to neglect of monitoring and management (43).” (348)
    • “Palm oil production in Indonesia is expected to continue to increase by almost 30% above 2012 levels by 2019 (44).” (348)
  • Approaches to addressing mangrove deforestation need to take into account the differing motivations for mangrove conversion in different countries.
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