title: Enhancing koala conservation through the improved use of linear infrastructure mitigation measures in South East Queensland
Creators: name: Dexter, Cathryn E
Publisher: name: Griffith University
Year: 2021
Subjects: subject: koala conservation
subject: South East Queensland
subject: wildlife road mitigation measures
subject: movement corridors

description: Species survival in fragmented landscapes is linked to their mobility and potential for dispersal to ensure gene flow. In recent decades government agencies globally have been tackling the challenge of safeguarding landscape permeability for wildlife. This has primarily been addressed through the acquisition of land to restore habitat and through the creation of movement corridors. To address wildlife vehicle-strike, transport authorities have created fauna passages, over and under new roads, or retrofitted existing road infrastructure, such as culverts or bridge underpasses, to facilitate safe animal movement across landscapes with extensive road networks. The principal function of fauna crossing structures are to provide connectivity between severed countryside and animal communities. Crossing structures that are connected to fauna-friendly fencing that stop animals from entering road corridors and funnel animals toward crossing structures have been shown to increase the ecological benefits of these structures. However, poorly planned and designed wildlife road mitigation measures that ignore gene flow as a fundamental requirement for ongoing population viability, may become a waste of public funds and create a variety of ecological problems. Despite significant investment in the development, design and placement of wildlife road mitigation measures worldwide, and several decades of research, information on the effectiveness of these measures still remains scant. This is largely due to insufficient reporting or poor research objectives and monitoring regimes. Therefore, many important issues and higher-order ecological questions persist. Two of the most pertinent are: 1) what is the optimal placement for wildlife road mitigation measures and; 2) once in place, do these mitigation measures meet their conservation goal, particularly the maintenance of population viability at both a local and landscape level? In urban environments wildlife population viability is impacted by the ability to safely move between suitable habitat remnants, and while some species, for example birds, may readily move across linear barriers such as roads, other species, including many that are threatened, are more heavily affected by roads. In South East Queensland, koalas (Phascolarctos cinereus) are in serious decline. A primary cause has been attributed to habitat loss and fragmentation and associated road related mortality due to rapid urban expansion in this region. Koalas are particularly susceptible to vehicle-strike, and effective mitigation measures that can reduce road-related impacts and that support the long-term persistence of populations in the landscape, are urgently required. This thesis focussed on the effects of roads and vehicle-strike on koala populations within South East Queensland. The primary aim was to advance koala conservation efforts hampered by the impacts of linear infrastructure. My investigations centred on how to improve on existing actions and past practices to achieve better conservation outcomes at both the local and landscape level.