New research from The University of Western Australia has highlighted the impact of the 2023-24 summer's extreme heat and drought on Perth's ecosystems.
The study co-authored by Dr Caitlin Moore and Associate Professor Sally Thompson, from the Centre for Water and Spatial Science in UWA's School of Agriculture and the Environment, was published in Environmental Research Letters.
"The hot, dry conditions of summer 2023 led to significant dieback across Perth's Banksia woodlands and Jarrah forests, with evidence suggesting some ecosystems may have reached stress tipping points," Dr Moore said.
In 2023, groundwater, vital for both the environment and urban areas, saw significant declines.
"This meant trees that typically rely on groundwater reached known access limits, or were unable to sustain their usual health, such as in northern banksia woodlands where greater dieback was evident," Dr Moore said.
"This is the first sign of a concerning trend, as these ecosystems have been predicted to be among the most vulnerable to climate-induced drying."
The research used over a decade of observational and remote sensing data and found the resilience of groundwater-dependent systems was being impacted by expanding urbanisation and increased extraction from Perth's Gnangara groundwater aquifer.
The actions being taken under the Gnangara Groundwater Allocation Plan to reduce human pressures on the aquifer were shown to be vital to address the vulnerability of ecosystems.
Associate Professor Thompson said she hoped the research would kickstart a conversation between planners and policymakers.
"The health of our native ecosystems is directly linked to our groundwater practices," Associate Professor Thompson said.
"Our research highlights the importance of researchers and water managers collaborating on environmental planning and water management."
The research was supported by the Australian Terrestrial Ecosystem Research Network through the Federal Government's National Collaborative Research Infrastructure Strategy fund, and the Western Australian Department of Water and Environmental Regulation through the Recharge Estimation Collaboration and Recharge in a Changing Climate projects.
