No 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.

African boxthorn (Lycium ferocissimum Solanaceae) is a Weed of National Significance in Australia. It is particularly problematic in Victoria and is thought to not only threaten native wildlife but also provide important habitat, particularly to birds, when there is no native alternative. In a wetland ecosystem such as a saltmarsh, boxthorn has the potential to increase structural complexity because it can stand as an emergent above surrounding vegetation. We compared bird assemblages and behaviour in saltmarsh vegetation with and without boxthorn in a coastal wetland in south-east Australia. Species assemblage, but not richness, changed with the presence of boxthorn. The presence of singing honeyeaters (Lichenostomus virescens) and white-fronted chats (Epthianura albifrons), the two most common native bird species (based on numerical and spatial dominance), appeared to drive these differences; singing honeyeaters preferred boxthorn while white-fronted chats avoided it. The presence of boxthorn increased the seasonal availability of fruit and flowers, which was reflected by a high frequency of foraging for fruit and nectar where boxthorn was present. In saltmarshes without boxthorn, there was a higher frequency of foraging for insects. Some, but not all, species responded to increased structural complexity and fruit/ floral resources provided by boxthorn. Consequently, management by reducing boxthorn is likely to alter bird communities and the usage of sites by some native species, thus management success should consider fine-scale biodiversity objectives, such as managing for particular types or species of birds.

Weed management often involves active measures to minimize or prevent negative impacts on local wildlife. Approaches include retention of weed structure, altered timing of management to avoid wildlife breeding seasons, and/or the gradual removal of weeds in conjunction with revegetation of native plants. We assess the short‐term impacts of retaining some structural complexity offered by weeds post management to birds and a small mammal in two ecosystems. One ecosystem involves a wetland with an emergent weed, the other a woodland with a sub‐canopy weed. Before‐After‐Reference‐Control‐Impact experiments revealed that assemblage and activity of birds and an invasive small mammal—the only captured in numbers during our study—were minimally altered by weed management. In some instances, we observed the activity of native bird species favoring the use of weeds. Evidence also suggested the weedy sites supported different species assemblages compared to reference sites without weeds. This study indicates that, in the short‐term, retention of weed structure can sustain birds and an exotic mammal that use weeds.