A 22-year study has found growth in ant numbers, a positive story for the fragile Simpson Desert ecosystem.
A long-term study led by the University of Sydney鈥檚 and in collaboration with La Trobe University has found that changes in climate in the Simpson Desert, such as increased rainfall, may have led to an increased number of ants and increased activity in ant communities.
This is unexpected given previous and the so-called Insectageddon.
鈥淥ur findings are important as ants are truly the workers of the desert,鈥 Professor of Ecology and Evolution said. 鈥淎lways present, always active, come rain or shine. Ants contribute in so many ways by tending plants and helping them to reproduce by moving pollen or seeds. Ants are in turn food for many desert fauna species.鈥
View of dunefields on Ethabuka Reserve, Simpson Desert, with an open pitfall trap in the foreground. Usually red, late summer rain in 2019 stimulated a flush of new plant growth to turn the desert into a vibrant green just two months later. The ant fauna responds dramatically to these rainfall events.聽Photo: Chris Dickman.
The study published in the , covers a 22-year-period, when annual rainfall fluctuated between 79聽mm and 570聽mm.
The Desert Ecology Research Group sampled ants using pitfall traps in paired dune and swale habitats (a shallow trough) in the Simpson Desert, Australia. They used climate records over this period to model changes in ant communities.
鈥淎nts are ecologically very important in Australia鈥檚 desert regions, acting as predators, scavengers, pollinators, seed dispersers, soil engineers and prey for specialist vertebrates, such as the iconic thorny devil lizard,鈥 said , from the Desert Ecology Research Group in the School of Life and Environmental Sciences.
鈥淭his research 鈥 one of the world's longest-running studies of desert invertebrates 鈥 describes for the first time the dynamics and astonishing diversity聽of the 106 ant species in the study area."
Thorny devil lizards feed on ants. Photo: Glenda Wardle
鈥淎 key finding of the study was that activity of the dominant ants increased dramatically following long-term increases in rainfall, and increases occurred also in the richness of other ant groups,鈥 Professor Dickman said. 鈥淲hile species鈥 composition fluctuated over the period of study, the results show that the desert ant fauna, at least, is not suffering the devastating declines in numbers that are occurring with insects in many other parts of the world."
Professor Wardle said: 鈥淭he main finding from this study based on long-term field collected data is that ants respond to productivity during wet years but are not declining overall. This finding contrasts with the reported global decline in insects.鈥
鈥淎nts may be small but the way they respond to resource pulses in arid Australia tells a big story,鈥 Professor Wardle said. 鈥淥ur study found that over the 22-year period ant communities showed changes in composition but did not decline.
Long-term ecological studies are crucial to tracking the health of ecosystems. has been doing this for 30 years. DERG is working on how animals and plants can survive dry conditions
Led by Professors Chris Dickman and聽Glenda Wardle, with critical support from Dr Chin-Liang Beh, Mr Bobby Tamayo (Operations Manager) and early-career researcher Dr Aaron Greenville, DERG aims to track shifts in biodiversity in arid Australia and identify and mitigate the processes that drive biodiversity declines.
Declaration: Funding for this project was provided by the Hermon Slade Foundation, the Australian Research Council and the Long Term Ecological Research Network, an Australian research infrastructure facility established under the National Collaborative Research Infrastructure Strategy and Education Infrastructure Fund鈥怱uper Science Initiative through the Department of Industry, Innovation, Science, Research and Tertiary Education.聽