Abstract：

Being neither terrestrial nor marine, tidal wetlands are poorly mapped, and our understanding of how their distribution is changing over time is extremely limited. For biodiversity and ecosystem services that depend on tidal wetlands globally, this is a serious shortfall. Here I present maps of tidal wetlands globally using a newly-derived remote sensing method, and show how tidal wetlands have changed in extent and distribution over the past few decades. I discuss natural and anthropogenic drivers of this change, and provide a prognosis for the global conservation of tidal wetland-dependent biodiversity and ecosystem services.