Tracking continental scale changes in mangrove extent using Digital Earth Australia

Dr Leo Lymburner1, Dr  Peter  Scarth2, Dr  Richard Lucas3, Mr  Peter  Bunting3, Dr Catherine Ticehurst4, Dr  Claire Phillips1

1Geoscience Australia, Symonston, Australia, 2University of Queensland, Brisbane, Australia, 3University of Aberystwyth, Aberystwyth, Wales, 4CSIRO , Canberra, Australia


Mangroves provide a range of essential ecosystem services, from coastal protection, habitat provision and carbon sequestration.  However mangroves are impacted by a wide range of natural and anthropogenic drivers leading to losses and gains in mangrove extent.  Multi-decadal archives of satellite imagery provide a unique opportunity for tracking changes in mangrove extent over time at continental scales.  The Digital Earth Australia (DEA) contains 3 decades of Landsat satellite surface reflectance which has been converted into fractional cover using algorithms developed by the Joint Remote Sensing Research Progam.  The green cover fraction measures the percentage of each pixel that contains green vegetation.  For vegetation with little or no understory such as mangroves, the 25th percentile of green cover fraction observed per year can be used to provide a consistent measure of canopy cover.  The 25th percentile of the DEA fractional cover product for each calendar year between 1988 and 2017 was calculated and a mangrove extent mask, based on the Global Mangrove Watch polygon was applied.  The result is a series of maps that show the mangrove canopy cover for each year.  This talk describes the mangrove canopy cover product with examples of how canopy cover has responded to disturbance events such as severe tropical cyclones.


Leo Lymburner has been working in the field of remote sensing since 1998.  He gained his PhD in remote sensing of riparian vegetation in 2006 and has been working at Geoscience Australia on land cover mapping and data cube applications since 2008.  Leo a member of the Landsat Science Team.