Top of page

Student/Staff Portal
Global Site Navigation

School of Science

Local Section Navigation
You are here: Main Content
  • Black Swans

    A pair of black swans excluded from the study area. Image: Andrew Ritchie

Related Contents

Plant-herbivore interactions in a changing climate and implications for seagrass recovery

Estuaries create a vital link between the terrestrial and ocean ecosystems, and provide key ecological and socioeconomic services. Climate change poses a major threat to seagrass habitats within estuarine environments, through a number of simultaneously acting mechanisms. While this is understood conceptually, the overwhelming majority of studies to date have focused on single stressors; few have experimentally tested the resilience of seagrass meadows to multiple disturbances. Grazing by waterfowl is a natural disturbance to seagrasses in estuarine systems. Future warming is predicted to increase the density of swans in estuaries, as surrounding wetlands habitats shrink, thereby adding not only thermal stress but, simultaneously, increased grazing pressure.

The iconic black swan is one of the most prolific grazers of seagrass in temperate estuaries worldwide, including south-west Australia. In a field experiment that excluded swans from the study area in the field, this project has experimentally investigated the combined impacts of black swan grazing and temperature on the recovery of Halophila ovalis (or paddleweed). Some preliminary key findings:

  • The time taken for seagrass to recover increases with intensity of grazing pressure,
  • Greater grazing intensities introduces greater variability in recovery time.
  • The key recovery mechanism of recovery is through vegetative regrowth from the surrounding meadow.

This research aims to provide valuable insight into the recovery time of seagrasses after multiple interacting disturbances. The results may be used to inform seagrass ecosystem management and facilitate realistic management timelines.

Funding agency

School of Science - ECU
Ecological Society of Australia – Holsworth Wildlife Research Endowment

Project duration

2018 - 2021

Researchers

Ms Caitlyn O’Dea (Masters student)
Associate Professor Kathryn McMahon
Professor Paul Lavery

Skip to top of page