Some like it wet: the impacts of climate change on local plant life

Some indigenous plants have been flowering later this year because of the cool, wet weather, prompting nursery workers to worry about climate change.

But, according to researchers at the Royal Botanic Gardens (RBG), other species have been lapping up the rain and coming back from the brink of extinction.

Megan Hirst, a postdoctoral fellow in seed science, and her colleagues at the Gardens have been comparing notes about the changes.

Dr Hirst said that plants in the Gardens were growing in a semi-controlled environment under a curator’s care and attention in which irrigation was monitored, and fertiliser applied if necessary.

“However, it is the plants in the wild that do not have this buffering from seasonal variation. Flowering appears to be later in some indices,” she said.

Late flowering has had an impact on the collection of seed for propagation at Westgate Biodiversity, a nursery which specialises in local plants.

Southbank News began investigating the issue after getting a tip-off from workers who collect the seeds from indigenous plantings in the City of Melbourne.

The workers collect seed from species such as Lomandra or mat rush, a local grass once prevalent among the open eucalypt forests of the riverbank, and now only available in cultivated form. 

Christopher Jakobi, a facilitator of RBG Aboriginal programs, has been keeping an eye on the grasses in the Gardens.

“In the Gardens at the moment, as expected, grasses tend to be flowering at this time of year and in one to two months they should be producing seed,” he said.

“I can see the seed heads on the Kangaroo Grass, Themeda triandra, and I can see that Grevillea trees, Grevillea robusta are in flower – there is one near The Terrace and one on Oak Lawn.”

However, on a recent trip to Portland with the science team, “we did notice that the orchids were flowering about six weeks late”. 

He said that plants in the Gardens were more insulated from changes to the environment.

“It is the same in Southbank and in cities. Cities experience the urban heat island effect, and if they need more water, people tend to water them.”

Seeds are collected from native species growing in the Gardens and stored in the nursery while other rare and threatened Victorian species are collected in the wild and stored at the Victorian Conservation Seedbank. 

Dr Hirst said that the changing climate has had an impact on species that are very habitat-dependent, some for the better. 

“Some like it wet!” she said. “For example, we are currently working with the Swamp Everlasting, Xerochrysum palustre and it is doing exceptionally well.”

“This critically endangered species naturally occurs in lowland swamps but has become rare due to habitat depletion.”

“We have collections of this species in cultivation currently flowering and is showing robust growth in the outdoor research plots given all the rain.”  

Council calls for local input on Southbank Community Resilience Assessment

The City of Melbourne is still calling on all Southbankers to participate in an online survey as part of its “Southbank Community Resilience Assessment” until December 19. 

Locals can have their say on the assessment via the Participate Melbourne online portal. The council says it is conducting the assessment in response to climate change and the likelihood of “disasters” becoming more difficult to manage. 

Southbank has a history of flooding events being a low-lying area along the Yarra River. The council said it was working on a four-year project called “Prepare Melbourne” to engage, and prepare residents and communities to “enhance their resilience” to such events, as well as the health impacts of climate change.

Starting with Southbank as a pilot neighbourhood, the council says it would like to better understand the physical and social vulnerabilities its communities face. •

Caption: Healthy stock of lilly pilly and chocolate orchids are benefitting from the rain.