Between 2018 and 2021, Uluṟu-Kata Tjuṯa National Park in Australia's interior experienced the most severe drought on record. Temperatures this century have been much higher than in earlier droughts, bringing longer, hotter and more frequent heat waves than any other period in recorded human history.
Following record-breaking heat waves in 2019 to 2020, mass mortality struck usually robust plants including kurkaṟa (desert oak), wanaṟi (mulga), and pukaṟa (desert heath myrtle). Using 360-degree imaging, scientists and Muṯitjulu Mala Rangers found that plant dieback covered hundreds of square kilometers within the park alone.
On-Country surveys found plant species died at different rates. Seventy-eight percent of kurkaṟa survived the drought, but only 10 percent of pukaṟa survived.
Research suggests that how plants use water explains the different survival rates. Species with low rates of dieback tended to slow their growth and conserve water in their tissues. Species more likely to die were those that continued to use water for growth during summer, a strategy that might work in mild drought but can lead to rapid water loss and death by dehydration during severe drought.
Aṉangu Muṯitjulu Mala Ranger Natalie Ray said, "When we go out to look around, we see the numbers going down."
As native plants die, invasive buffel grass spreads rapidly through the park, crowding out native species and choking waterholes. Animals dependent on native plants are also suffering, with Aṉangu observing hardy desert lizards dying and birds dropping from trees during extreme heat waves.
Aṉangu, scientists from Parks Australia, CSIRO, and universities have partnered since 2020 to understand how climate change affects plants at Uluṟu-Kata Tjuṯa. Aṉangu and scientists co-designed and conducted linked research projects to understand which plant species coped better than others.