The historic property of Marchwiel at Marion Bay in Tasmania’s southeast was the site of a mass restoration planting on Thursday, 5 September involving staff from the University of Tasmania’s ARC Centre for Forest Value, Greening Australia and Conservation Volunteers Australia.
The planting at Marchwiel is part of two research trials which will not only help increase biodiversity at the property but also guide climate-resilient restoration plantings and inform conservation strategies into the future.
The trials involve two eucalypt species under threat at their existing distribution locations.
One of the species, Eucalyptus morrisbyi (Morrisby’s gum), is one of Australia’s most endangered eucalypts and is only known from two main populations near Hobart in southeast Tasmania – Risdon Hill and Calverts Hill.
“The Calverts Hill population was a large, healthy population of around 2000 trees until around 2012, when the population began declining to a point where there are now only five adult trees remaining, none of which produce seed,” said Dr Rebecca Jones from the Centre for Forest Value.
“The main cause of this decline seems to be a combination of insect and possum browsing, possibly combined with climate induced stress,” she said.
This dramatic decline sparked a recovery project involving stakeholders such as the University, Enviro-dynamics, NRM South, Tasmanian Parks and Wildlife Service, DPIPWE, the Tasmanian Seed Conservation Centre at the Royal Tasmanian Botanical Gardens, Conservation Volunteers Australia, Threatened Plants Tasmania, the Understorey Network and pakana services.
At Marchwiel, the University, Greening Australia and Conservation Volunteers Australia are establishing a genetically diverse planting of trees from both the Risdon Hill and Calverts Hill populations outside the species distribution, in areas predicted to be suitable climate habitat for the species in the future.
The second species being used in the trials is Eucalyptus viminalis, which is widespread in Tasmania and a critical food resource and habitat for many animals, including rare and endangered bird species such as swift parrots and the forty-spotted pardalote. It is also one of the main eucalypt species used for woodland restoration in the Tasmanian midlands.
“This species is in rapid decline across its natural distribution following ginger tree syndrome which is believed to be in response to heat and drought stress,” said Dr Peter Harrison from the Centre for Forest Value.
In collaboration with Greening Australia, the University will establish a number of comparable field trials along an aridity gradient from inland Tasmania to the coast, of which Marchwiel is one site. These trials will help disentangle drivers of local adaptation which will inform conservation and restoration strategies in the face of an uncertain future environment.
Pictured from left; Professor Brad Potts and Dr Rebecca Jones measuring E. morrisbyi