Final answer:
Climate change is not acting on a 'clean slate' in relation to biodiversity, especially in the south-east Queensland region where human activity has already impacted the landscapes and biodiversity. This makes it harder to manage and mitigate the effects of climate change on existing biodiversity.
Step-by-step explanation:
The statement by Mac Nally et al. (2008) suggests that climate change does not occur in isolation but rather has an impact on existing biodiversity. In the context of the south-east Queensland region, this means that climate change is affecting biodiversity that already exists in the area. The region has undergone significant changes due to human activity such as deforestation and agriculture, which have modified the landscapes and created obstacles for species to move in response to climate change. This makes it harder to manage and mitigate the effects of climate change on biodiversity in the region.