Australian mangroves through the Holocene: interactions between sea level, mangrove extent, and carbon sequestration

Abstract Mangroves have shifted in position on the Australian coastline in association with sea-level fluctuations associated with climate change over a range of timescales. Relative sea-level rise following the last glacial maxima has driven mangroves across shallow continental margins punctuated by periods of relative stability and mangrove development on the continental shelf. The slowing of relative sea-level rise following 8000 BP coincided with widespread mangrove development, particularly across the tropical north of the continent. The stabilization of sea level by 7000 BP and probable subsequent decline promoted the infilling of estuaries and the replacement of mangrove with upper intertidal and supratidal habitats in many estuaries. In recent decades, mangrove landward encroachment has reversed some of these longer-term trends and is expected to continue under projected trends in relative sea level. Measures of mangrove vertical accretion utilizing the surface elevation table–marker horizon technique suggest that mangroves are currently keeping pace with sea-level rise and represent an important carbon sink.