Processes and Factors Driving Change in Mangrove Forests: An Evaluation Based on the Mass Dieback Event in Australia’s Gulf of Carpentaria

Abstract

A vast area of more than 80 km2 (6–10% of total) of mangrove forests bordering Australia’s Gulf of Carpentaria died en masse in late 2015 and early 2016. The dieback occurred over a number of months in synchrony across more than 1500 km of exposed Gulf shorelines. There are serious concerns about the implications of such an event given the important ecological and economic services provided by mangrove ecosystems, and the challenges to policy and management of such an abrupt loss of natural resources at both local and regional scales. In this chapter, we begin by structuring and quantifying the distinct and complex mix of processes involved in the natural establishment, growth, and development of mangrove stands in the context of enhanced environmental variability. Based on these findings, we develop a new evaluation framework to explain the severe response observed in late 2015 in mangroves of the Gulf of Carpentaria. We explore in detail the multiple drivers involved in the event and address the complex question of the role of climate change. These analyses and other observations about this unique event are brought together to assist the ongoing development and implementation of effective management policy, starting with monitoring programs at national and local scales. While this is a work in progress, these findings already provide unequivocal evidence that mangroves are vulnerable and acutely sensitive to extreme variations in sea level and climate change.