Between 1967 and 1999, more than 3,000 hectares of seagrass were lost from Cockburn Sound.
Now, Siegy Kraus, Kingsley Dixon and Liz Sinclair from Kings Park, Gary Kendrick, Marion Cambridge and Renae Hovey from UWA's Oceans Institute, and PhD student John Statton are uncovering the best methods for restoring seagrasses through the Seagrass Research and Rehabilitation Plan (SRRP).
Seagrasses, killed off by industrial pollution and eutrophication, play a crucial role in our coastal ecosystems. They provide homes and food for a myriad of ocean creatures, from small sponges and snails to crabs and fish. Shallow, sheltered seagrass meadows provide vital nursery areas for many commercial fish and crustaceans, including the Western Rock Lobster - Western Australia's most valuable fishery.
The challenges of working underwater mean that much less is known about these flowering plants than their terrestrial counterparts. Dr Sinclair, research scientist at Kings Park and the School of Plant Biology, says that seagrass rehabilitation must piece together knowledge from both ecology and genetics to be truly successful.
"There's a whole field of people studying the practical side of things - how to collect seagrasses, how to plant them," Dr Sinclair said. "The genetics work I'm doing will be used to identify the species we want to restore, and figure out where to source plant material."
On land, restoration ecologists recommend re-establishing plants with a similar genetic makeup to the original plants lost through clearing. Introducing distantly-related plants, even of the same species, can ‘pollute' the gene pool and make the population vulnerable to environmental changes.
With these principles in mind, Dr Sinclair is using the latest genetic technology to investigate the DNA of a variety of Western Australian seagrasses. The results will guide the collection of donor plants, and maintain the genetic composition of seagrass populations in the restored sites.
She is confident that the seagrass meadows can be restored. "In calmer waters, where seeds can settle, seagrasses will recruit naturally. But other sites have changed so much that they're going to need a huge amount of help."
The stark changes began in the late 1960s, with effluents from industry along the shores of Cockburn Sound polluting the water and spawning algal growths that suffocated the seagrasses.
Published in UWA News, 23 August 2010