In March 2019 a Copernicus Sentinel-2 image (base layer) showed that an area of mangrove in Guinea-Bissau had been significantly destroyed.
Global Mangrove Watch regularly compares satellite images with a baseline map to generate ‘change alerts’ (inset, red/yellow patches overlaid on Google Maps). A closer look revealed that a new dam had been built (red circle).
Global Mangrove Watch sent people on the ground to the site. They saw that the government had built the dam to turn the mangrove into rice fields. There was nothing that could be done to prevent the transformation, but often in these cases the rice fields are tended for a few years, then the mangroves grow back.