Study system
Our study was conducted in the York gum woodlands of West Perenjori Nature Reserve (29°28′01.3″S, 116°12′21.6″E) in semi-arid south-west Western Australia (Fig. 1). York gum woodlands have a diverse understory of winter annual plant species and a sparse overstory that creates local-scale variation in shade and litter cover, which has been associated with annual plant species turnover (Dwyer et al. 2015; Wainwright et al. 2017) and population growth of some species (Stouffer et al. 2018). In the broader region, substantial inter-annual variation in rainfall significantly influences annual plant community composition (Dwyer et al. 2015).