Each spring across Australia, its native golden wattle plants (Acacia pycnantha Benth.) burst into bloom in a riot of puffy, bright yellow flowers.
A member of the genus acacia—or as Australians refer to these types of flowering shrubs, “wattles”—the plant’s distinctive yellow blossoms and green leaves evoke the Australian national colors. Sprigs of wattle have been used to represent Australia for decades, notably decorating the colonial-era Commonwealth Coat of Arms. The plant was officially declared the national floral emblem in 1988.
Yet the wattle’s importance to human societies predates Australia’s colonial period by tens of thousands of years, as new research makes clear. In a paper published last October in the Journal of Archaeological Science: Reports, University of Western Australia (UWA) scientists explore how more than 100 species of wattle have been used by Aboriginal communities in Australia’s Western Desert for more than 50,000 years, reports Caitlin Cassidy for the Guardian.
Working with representatives from the Martu people, an Australian Indigenous group and the traditional owners of the land, UWA archaeologist Chae Byrne led researchers in excavating small parts of the ancient rock desert shelters of Katjarra (the Carnarvon mountain range) and Karnatukul (also known as the Serpent’s Glen). The team used archaeobotany—a combination of techniques from archaeology and botany used in the study of ancient plant remains—to analyze the clues left behind by ancient Indigenous wanderers who once camped here and took shelter from the harsh weather of the Western Desert.
Researchers first discovered evidence for the earliest-recorded human activity in this region: the remains of ancient campfires, which scientists estimate to be nearly 50,000 years old, according to Samantha Goerling of ABC News, the Australian broadcasting service.
The team then turned to examining the bits of ancient charcoal from the site, where they discovered what looked like the telltale traces of wood and seeds from wattle plants. Scientists confirmed their findings by comparing charcoal fragments with tree samples from the surrounding region, the latter of which still preserves key anatomical traits from its plant of origin after thousands of years, per the Guardian. Byrne used this information to conclude that wattle was being used as firewood even 50,000 years ago.
“Looking at plant remains is particularly useful in studying Australian Indigenous heritage, given the persistent importance of natural resources like trees and the rarity of other cultural remains in the deep time record,” Byrne says in a UWA press release.
Thanks to widely available wattle plants, Indigenous people were able to thrive in the dry desert landscape as it underwent drought and desertification, adds the Guardian.
“Wattle was critical to the lives of the Martu and essential to the habitability of the arid landscape of the sandplains and rocky ridges of the Western Desert—and it still is,” Byrne says in the statement.
The archaeologists say many Aboriginal communities today collect wattle seeds of several varieties and grind them into pastes, which can be used to make foods or medicines. “Then and now, wattle has been used as firewood, to make tools, as food and as medicine,” the researcher adds in the statement.
Wattle may have roots in deep time, but it also has a part to play in Australia’s future. Last year, seeds from this historic and versatile plant completed an eight-month stint aboard the International Space Station, as part of an Australian government program to encourage science education in schools.
Participating schools then received space seeds as well as normal wattle seeds. Students will plant the seeds and monitor their growth in a nation-wide investigation to determine the impact of microgravity on plant growth, per an Australian Government statement.