Drivers of global mangrove loss and gain in social-ecological systems

Background

The gain and loss of mangrove forests worldwide depends on both biophysical factors and socioeconomic factors. With global mangrove cover decreasing since the 1990s and biophysical pressures on mangrove forests (i.e., shoreline erosion, extreme weather events) increasing due to climate change, it is important to understand which forms of national conservation policies, programs, governance, and local economic activity most rapidly reverse the rate of loss of mangrove forests.

Goals and Methods

This study uses a high-resolution, global time-series to document mangrove cover loss and gain over two decade-long time periods (1996-2007 and 2007-2016). By applying hierarchical modeling to the mangrove cover data, the authors calculate how socioeconomic and biophysical variables correlate with percent net loss, percent net gain, percent gross loss, and percent gross gain of mangrove forests.

Conclusions and Takeaways

This research documents a decline in the global rate of net mangrove loss between the two decades (2.74% to 1.58%). Access to markets and shorter travel time to the nearest city correlate with greater mangrove loss, due to the conversion of mangrove forests into land for agriculture or aquaculture. The relationship between economic growth and mangrove forest change was negative during the first decade, but was positive in the second decade. Economic development during the first decade, due to mangrove forest land use changes, led to increases in wealth, education, and agricultural productivity. The decreased need to develop new land caused the relationship between mangrove forests and economic growth to change during the second decade. Additionally, there is a positive association between community forestry and mangrove gains, which provide additional social benefits to the communities by addressing tenure rights, development, and governance needs.