Does Buffel Grass (Cenchrus ciliaris) invasion impact plant-animal interactions in an arid system?

The invasion of exotic grasses is transforming arid landscapes across three continents, changing fire regimes and leading to a loss of floristic diversity. The indirect impacts on fauna, ecosystem processes and cultural values of indigenous peoples whose lives are closely intertwined with country have not, however, been well documented. Aṉangu people in the Aṉangu Pitjantjatjara Yankunytjatjara (APY) lands of North-west South Australia are concerned by the large-scale changes brought about the rapid invasion of buffel grass (Cenchrus ciliaris) throughout much of their ancestral lands over the past 25 years
This research aims to investigate the impacts of invasion on animal communities, plant-animal interactions, and vegetation change, including aspects which are important to Aṉangu people. The main components of the study conducted collaboratively with Aṉangu: (1) comprehensive biological remonitoring after 25 years of sites that have, and have not, subsequently been invaded by buffel (2) observational experiments comparing seed production in buffel-dominated grasslands with native grasslands that support the staple bushfood Eragrostis eriopoda (wanguṉu), and linking this to the foraging behaviour and density of ants and rodents, which are important seed-harvesters.
Preliminary results show that some animal species are persisting in both heavily-invaded and uninvaded sites, whilst others are impacted. For example, the community composition and abundance of small mammals was similar between native sites and those sites matched for habitat type but now heavily invaded. However, the density of seed-harvesting ant colonies is significantly lower in heavily invaded sites, which could be linked to the lower diversity and abundance of native grass seed produced. Over 30 people have been involved in the research, including many Anangu, with additional engagement with schools and the wider community. Overall this study is providing valuable feedback about ecosystem components including those of particular importance for Anangu that are disrupted or persisting with buffel grass invasion.