An extensive mangrove dieback event occurred in the Gulf of Carpentaria over the austral summer of 2015 to 2016. The event was unprecedented and resulted in the loss of approximately 7000ha of mangroves, over 1000kms of coastline and coincided with low rainfall, high temperatures and a lowering of the mean sea level. This study focused on identifying the spatial and temporal variations in mangrove dieback, at a local (site) and a regional (Gulf) scale, due to the lowering of sea levels. This was undertaken utilising several datasets ranging from satellite imagery products to Lidar data and site-based ground-truthing, with the application of novel concepts to link regional sea level variability to local dieback sites. Spatial variability in mean elevations of dieback highlighted correlations to mean high tide ranges in the north and south of the Gulf, with some sites statistically different in elevation to other sites nearby. Temporal variability of dieback onset also occurred across the Gulf with mean sea level seasonality playing a large role, promoting dieback onset in the southern regions before the northern regions. The mangroves have shown vulnerability to a changing sea level, and whilst the lowering of MSL was event driven, it is likely the fast rate of change during the severe 2015-2016 ENSO event did not allow some mangroves to shift or adapt. This dieback event may serve as an early warning of what may happen if the rate of sea level rise and fall increases, due to climate change. Rapid perturbation will result in dieback as this will offset the ability of mangroves to rapidly colonize available niches.
|Date of Award||1 Jun 2021|
|Supervisor||Lindsay B. Hutley (Supervisor)|