From Gardening Australia SERIES 31 | Episode 02, FEBRUARY 14, 2020
Secret World of Saltmarshes
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More than 85% of Australians live, work and garden within 50km of the coast, and we’re famous for our beach lifestyle. But when we visit the beach we often cross over the most important and fascinating ecosystems, without even noticing the unique plant species that exist there - in the saltmarshes.
Saltmarshes form a crucial link between land and marine ecosystems. They act like a huge filtration system, slowing fresh water moving off the land, removing sediments and excess nutrients, which regulates algal blooms and prevents silt covering the seagrass beds offshore. Saltmarshes are flooded at high tide and dry out at low tide and the plants here have adapted to these unusual conditions, which includes high levels of salt.
Ecologist Dr Vishnu Prahalad has been studying saltmarshes at the University of Tasmania for more than a decade and he’s passionate about introducing Australians to “the riches behind the beaches”. Tino meets him at Marion Bay north of Hobart to explore. Vishnu says he started looking at the plants but found he couldn’t look at them in isolation from the fish, animals and birds that live there.
He also meets botanist Andrew North, who lives nearby. “Salt marshes are like the lungs of the marine system,” he says. He points out some glassworts that have turned red and explains this is due to the plant being stressed – maybe too much salt or too little water – so it turns red to slow down the process of photosynthesis until it can recover.
Andrew is a member of the Marion Bay Coastcare group, a group of volunteers who are working with Vishnu and the university to remove weeds and monitor the native plants in the area to see if there’s any changes. “It’s very valuable the work that they’re doing,” says Vishnu. “This is their backyard and they get to see it every day. Saltmarshes are part of our global garden. These ecosystems need care – they’ve been impacted by human activity in the past – so in that sense we can be involved in gardening the ecosystem.”