Invasive African boneseed and a native shrub support similar faunal assemblages in a heavily infested landscape

Abstract

Invasive weeds may provide habitat for wildlife in altered landscapes. We compare fauna within three types of sites in You Yangs Regional Park in central Victoria, Australia, that is, sites with an invasive shrub understory (African boneseed, Chrysanthemoides monilifera subsp. monilifera (DC.) T. Norl.), native shrub understory (snowy mintbush Prostanthera nivea), and sites without an understory (open sites).Sites with an understory dominated by boneseed provided habitat for avian species and an introduced small mammal, comparable with sites with mintbush as the understory. Species-specific models of common species suggest vegetation structure, rather than composition, drove this effect. Open sites differed in terms of avifaunal assemblage, and the abundance of three common native birds and one common invasive small mammal. Boneseed additionally showed phenological differences in fruiting and flowering and differences in flowering abundance when compared with mintbush, comparably offering resources to wildlife. Transitioning vegetation communities to more natural states should consider wildlife already depending on weeds, a dependency likely driven by a paucity of alternative native vegetation.

Maintaining vegetative structure during weed management sustains birds and an invasive mammal

“…Consistent tall shrubs and low shrubs density after management in all sites confirmed a lack of substantial structural changes after weed management. Boneseed management did not impact canopy either, the most influential habitat variable for brown thornbills and superb fairy‐wrens at our study sites (Carlos et al 2023). This also suggests that weeds were not solely relied on for direct food resources, rather they used boneseed for structural cover and protection.…”

“…However, the invasive house mouse, only responded to weed management in the Woodland. House mice have previously been shown to be most influenced by lower structural complexity in these ecosystems (Carlos 2010;Carlos et al 2023) and elsewhere (Arthur et al 2004;Rendall et al 2014). Here, removal of boneseed may have imparted increased predation risk, which resulted in a reduction in the use of these sites by mice (Arthur et al 2004).…”

“…days without strong wind or persistent rain). In the Woodland, birds seen within a 50 m radius of the survey point were counted for 60 min (based on species accumulation curves in each system; Carlos et al 2023). In the Wetland, surveys were conducted in the position that afforded a view of the whole sampling area and were conducted for 30 min per bush (60 min per site, sensu Carlos et al 2014).…”

“…Norl.) that occurred throughout 65% of the park (Roberts 2008;Carlos et al 2023). The second site was at Cheetham Wetlands (hereafter "Wetland"; 37 54 0 S, 144 48 0 E), a disused saltworks that was heavily infested with African boxthorn (Lycium ferocissimum Miers.)…”

“…We investigated the short‐term impacts of small‐scale, perceived wildlife‐friendly weed management—that is herbicide application which kills the weeds but maintains structural complexity conferred by the weeds in the landscape—on birds and small mammals. We monitored faunal communities throughout weed management that retained vegetation structure in two ecosystems, and which have been previously surveyed to understand the impacts of weeds on these species (Wetland: Carlos et al 2017; Woodland: Carlos et al 2023). We predicted that management would result in limited shifts in wildlife species detected supporting the assertion that this management technique is indeed “wildlife friendly”.…”