Anthropogenic activity threatens biodiversity worldwide, with the species and ecosystems of even the most remote and largest remaining wilderness at risk. In Antarctica, human activity is growing, barriers to invasive species establishment are being lowered, pollution is pervasive, and climate change directly and indirectly threatens taxa across the region. This has the potential to impact some of the world's most unusual, isolated, and highly-adapted species. Evolving in isolation for long periods, a number of specialised lower plants and invertebrates dominate Antarctic ecosystems, with mosses, lichens, microbes, arthropods and soil microfauna present across the continent. Seals and seabirds breed in coastal regions and two flowering plants survive in the milder conditions of the Antarctic Peninsula.In this thesis I provide crucial impact assessments for some of the key processes threatening Antarctic biodiversity, and produce the first inclusive, continent-wide prioritisation of management strategies for conserving Antarctic biodiversity in the face of multiple threats, which will help to inform decision makers in identifying cost-effective conservation strategies.The vast majority of Antarctic life survives only in the less than 1% of the Antarctic continent that is permanently ice-free, where soils and rocks areas emerge as nunataks, dry valleys, cliffs, fellfields, and coastal oases. Despite being crucial habitat, we have limited understanding of how ice-free areas will be impacted by climate change. In Chapter 2 I use temperature-index melt modelling to determine the potential impacts of climate change on Antarctic biodiversity habitat. I found the distribution and extent of ice-free areas may rapidly change in the future, with up to 25% more ice-free area potentially available by the end of the century. The increasing habitat availability and increasing connectivity is likely to benefit some native taxa, yet will also provide opportunities to non-native species, who pose one of the greatest threats to Antarctic biodiversity. Spread of both native and non-native species into isolated regions could result in increased genetic homogenisation and reduced diversity.The milder coastal ice-free areas are home to great numbers of Antarctic taxa, as well as most sites of human activity, taking the form of scientific research facilities and tourist landing sites. Many of these low-lying sites may be impacted by sea-level change, yet there have been no comprehensive assessments of potential impacts for the Antarctic continent. In Chapter 3 I use three sea-level rise (0.5 m, 1 m, 2 m) and two sea-level fall (0.5 m, 1 m) scenarios to consider potential impacts of sea-level change on Antarctic biodiversity and human activity. I found sea-level rise could inundate prime coastal ice-free area, placing iii numerous research facilities, tourist landing sites, breeding penguin colonies and biodiversity hotspots at risk. Sea-level fall could further expose new ice-free areas and increase the distance to the coast for biodive...