Understanding the pysiological underpinnings of a massive mangrove die off in northern Australia

A project undertaken at the Hawkesbury Institute for the Environment, Western Sydney University, and supervised by Brendan Choat

In the latter part of 2015, an unprecedented die off of mangrove vegetation occurred along the Gulf of Carpentaria coast. This event caused the death of mangroves along a 1000 km swath of coastline, with around 7,400 hectares killed in a single month. At this point we have only limited insight into the physiological underpinnings of mortality in these mangrove communities. This includes knowledge of specific physiological thresholds at which mortality occurs in different species or populations of mangroves. In this project, we will bring together extensive expertise in the ecology of mangroves and cutting edge plant physiology, combined with dynamic remote sensing observations of mangrove canopy health, that will allow use to determine the vulnerability of mangrove communities to future extreme climate events in northern Australia.

Objectives

Our principal aim is to determine the physiological mechanism responsible for the Gulf of Carpentaria mangrove die off. The project will have two main components:
 
(a) a field study evaluating physiological traits of mangroves at sites across the Gulf of Capentaria and on the eastern coast Queensland, and
 
(b) evaluation of remote sensing data available for mangrove populations that suffered extensive damage during the die off compared to adjacent populations that suffered minor damage and to other populations that were not exposed to the extreme event.

Figure captions

Images show extensive die off of mangrove vegetation in the Gulf of Carpentaria after 2016. This mortality event caused the death of mangroves along a 1000 km swath of coastline, with around 7,400 hectares killed in a single month. Extensive mortality coincided with a period of extreme drought and heat but the underlying physiological cause of death remains unknown.  (photo credit Norm Duke).

Figures 1-3.