Defining thresholds and indicators of primary producer response to dredging related pressures
Dredging Science Program: Theme 5
Location: Pilbara and Kimberley
Project Leader: Paul Lavery, ECU
Telephone: 6304 5687
This project meets the needs of the State Government and industry to improve their understanding of how key primary producers are affected by dredging-related pressures.
There is almost no knowledge of how primary producers in the NW of Australia will respond to the environmental changes produced by dredging. Consequently, it is difficult to predict and then manage the impacts of dredging on these critical habitats with an acceptable level of certainty.
This project will improve our understanding of how seagrasses are affected by dredging activities, and will apply that understanding to better prediction of impacts and management of dredging.
A combination of laboratory and field experiments and field surveys will determine the levels of dredging-related pressures (or ‘thresholds’) that produce the earliest observable effects, sub-lethal effects and lethal effects on two species of seagrasses considered most ecologically important in the NW. The research will also determine the capacity of those seagrasses to recover from dredging-related stress.
The research will focus on two of the most significant stresses produced by dredging: the reduction in light availability to plants; and the smothering of seagrass and algae as suspended sediments settle.
The responses of seagrasses to dredging-related pressures will be characterised in order to identify plant or meadow features that can indicate the duration and the intensity of dredging-related stress that seagrasses have suffered. These indicators can be applied in monitoring programmes to identify stress and trigger management responses.
The research will enhance the capacity of government and industry to predict the impacts on dredging on key benthic primary producer ecosystems and, in so doing, improve the certainty and timeliness of key approvals and regulatory processes. It will also improve the capacity to manage the impacts of dredging through improved design of monitoring and management frameworks.
- McMahon K et al. Genetic variability within seagrass and implications for recovery potential 2017 WAMSI Research Conference (audio) Presentation slides
- Kendrick G et al. Thresholds and indicators of seagrass response to dredge pressures 2017 WAMSI Research Conference (audio) Presentation slides
- Strydom S et al. The influence of light quality on seagrasses 2017 WAMSI Research Conference (audio) Presentation slides
Centre for Marine Ecosystems Research Symposium - Australia’s northern seagrasses – resilience in the face of dredging (19 Sept 2017)
- Gary Kendrick et al. WAMSI DSN Theme 5.5: Primary Producer Response to Dredging Related Pressures (presentation slides)
- Simone Strydom et al. The influences of light quality on seagrasses (presentation slides) (audio)
- Paul Lavery et al. Thresholds and indicators of seagrass response to dredging pressures (presentation slides) (audio)
- Kathryn McMahon. Recovery dynamics of northern Australian seagrasses (presentation slides) (audio)
Strydom S, McMahon K, Kendrick GA, Statton J, Lavery PS (2018) Short-term responses of Posidonia australis to changes in light quality. Frontiers in Plant Science. Vol 8 17 Jan 2018 doi:10.3389/fpls.2017.02224
Statton J, McMahon K, Lavery P, Kendrick G.A. (2018) Determining light stress responses for a tropical multi-species seagrass assemblage. Marine Pollution Bulletin 128:508-518 DOI:10.1016/j.marpolbul.2018.01.060
Hernawan U, Van Dijk K, Kendrick G, Feng M, Biffin E, Lavery P, McMahon KM (2017) Historical processes and contemporary ocean currents drive genetic structure in the seagrass Thalassia hemprichii in the Indo-Australian Archipelago. Molecular Ecology DOI:10.1111/mec.13966
McMahon K, Evans R, van Dijk K, Hernawan U, Kendrick G, Lavery P, Lowe R, Puotinen M, Waycott M (2017) Disturbance Is an Important Driver of Clonal Richness in Tropical Seagrasses Frontiers in Plant Science doi: 10.3389/fpls.2017.02026
Strydom S, McMahon K, Kendrick G, Statton J, Lavery P.(2017) Seagrass Halophila ovalis is affected by light quality across different life history stages. Marine Ecology Progress Series DOI: 10.3354/meps12105
Strydom S, McMahon K, Lavery P. (2017) Response of the seagrass Halophila ovalis to altered light quality in a simulated dredge plume. Marine Pollution Bulletin doi.org/10.1016/j.marpolbul.2017.05.060