Protected, cleared, or at risk: The fate of Australian plant species under continued land use change

Abstract

Land clearing and protected area provision are two contrasting forces shaping the persistence of species in the landscape. Using Australia's flora as a case study, we characterize the three possible states of species persistence: protected, cleared, or at risk of future loss based on agricultural capability, using a comprehensive suite of plant distributions and traits. We test the assumption that plant species, assemblages, and growth forms are adequately preserved in protected areas in Australia, and contrast this result with historic and future loss driven by trajectories of continued land clearing. We find levels of protection and clearing are inversely related, with both bioregions and species with high levels of clearing having low protection. We find only one third of Australian bioregions meet international protection targets of 30 % of area in formal protection. Similarly, we find that 29 % of plant species have met representation protection targets (with 30 % of their range protected), while similar numbers (33 %) have clearing as the dominant land use across their ranges. Protection and clearing have also unevenly affected species with different growth forms, range sizes, and distributions across agricultural land capability. Narrow-ranged woody species (e.g., trees) are the most at-risk group in relation to clearing, whereas large-ranged non-woody species (e.g., graminoids, herbs) are afforded a high level of protection in reserved lands. We demonstrate that the Australian protected-area network, although theoretically underpinned by sound CAR principles (comprehensive, adequacy, representativeness), falls short in protecting both individual plant species and growth forms.