Over the past decade, about 100 hectares of these two species of eucalypts have died at the reserve as a result of intense periods of hotter, drier weather.
This has spurred Bush Heritage to embark on a long-term climate change adaptation experiment, which will take place over the next 70 years and more.
The experiment has been designed and run by Dr McDonald, a semi-retired entomologist (insect scientist), who volunteered with Bush Heritage because he wanted to contribute to global climate change action.
The experiment aims to find climate-ready eucalypt species for revegetation. First, areas of Australia were identified that are already experiencing the hotter, drier climate that Nardoo Hills will face in the next 90 years.
Then thousands of seeds were collected from grey box and yellow box trees in different locations across south-eastern Australia, including the Flinders Ranges in South Australia, and Quorn in NSW, where the climate is similar to that predicted for the northern Victoria region.
Over the coming decades, the survival rates of these introduced seedlings will be tracked, and it’s hoped they will cross-pollinate with local trees to produce a genetically-diverse woodland, better able to weather harsh conditions.
The goal was not to introduce entirely new species, because this might change the ecosystem function of the reserve, says Dr McDonald. “The animals and plants all coexist, they operate together in an integrated system.
“But we do have to give the two species affected a bit of a helping hand by introducing genetics that will help them deal with climate change over the coming decades,” he says.
A similar experiment into seed sourcing for future climates is under way in Tasmania, which compares mainland and Tasmanian trees and is run by the University of Tasmania.
The first 9000 seedlings were planted last winter and, after a very dry spring, many died. This variation was expected and will mean the sturdiest remain and create greater genetic variability, says Dr McDonald.
This week another 2700 were planted, with the trial’s plant propagation and site preparation financed by not-for-profit carbon offset provider Greenfleet. The progress of the seedlings will be tracked for decades to come.
“It’s so uplifting to be working on a project that should leave a positive legacy for decades if not a hundred years,” says Dr McDonald.
Miki Perkins is a senior journalist and Environment Reporter at The Age.