Subsistence Transitions and the Simplification of Ecological Networks in the Western Desert of Australia

The Australian desert ecosystem coevolved with humans over the course of fifty millennia, yet our understanding of the place of humans within the ecosystem is only now beginning to deepen; recent research suggests that the removal of Aboriginal people from homelands precipitated rapid ecosystem remodeling. We suggest that network-based approaches are instrumental in broadening our understanding of humans in ecosystems, so apply these approaches to examine nomadic-era ecosystems (when Aboriginal people lived exclusive foraging-based lifeways) and contemporary-era ecosystems (when Aboriginal people live a mixed-based economy lifestyle). Using the approach of food web modeling we explicitly place Martu Aboriginal foragers within the overall ecosystem of the Western Desert. By linking humans to the other biota in the desert, examining each species as nodes in a network and each consumption link as edges in the network, we can better understand the ways the network connectedness shifts between nomadic-era and contemporary-era food webs. Using network randomization simulations we show that the contemporary food webs deviate significantly from the nomadic era food webs, suggesting a key role of humans as “knitters” of the ecosystem. This work has implications for research on resilient ecosystems, both within Australia and beyond, and suggests that humans have significant roles to play in sustainability and resilience.