Seagrass ecosystems provide a multitude of ecological services, including their role as critical nursery habitat for a range of commercial and artisanal fisheries. These ecosystems occur in coastal systems that are both naturally disturbed, e.g. by cyclones, and anthropogenically disturbed and if their valuable ecological services are to be maintained, seagrasses must be resilient to these disturbances. Yet under climate change, disturbance regimes are changing, and it is uncertain how seagrasses will respond. In NW Australia the frequency and severity of cyclones is increasing as well as warming events will also impact seagrasses. Despite the magnitude of these impacts and the known importance of seagrass, very little is known about their resilience mechanisms in this region. Resilience mechanisms function to resist disturbance or to allow recovery post-impact.
The aim of this project is to understand the resilience mechanisms in tropical seagrass meadows in the NW of WA. A desktop study analysing photo transects aims to identify shifts in species composition and abundance potentially indicating the presence of successional patterns within the recovery trajectories of meadows in the Exmouth Gulf. An in-situ aquarium experiment will then be used to investigate whether a facilitation process is taking place during the recovery process in the Exmouth Gulf. This involves planting opportunistic species (Cymodocea serrulata) within trays of smaller colonising species (Halodule uninervis), these trays will then be subject to disturbance to see whether H.uninervis is facilitating the presence and growth of C.serrulata.
For management, understanding these resilience mechanisms is important to: 1) predict the impact of a disturbance and recovery times; 2) understand where a seagrass community is in its recovery sequence and, therefore, its vulnerability; and 3) implement strategies that support resilience, so that alternative ecological states are not formed.
Project link: Seagrass Resilience: Exploring recovery trajectories, succession and facilitation.