The sub-Antarctic islands are amongst the most isolated islands from any continental landmass and contain a large part of the limited terrestrial habitats present at these latitudes. Interestingly, our knowledge of the terrestrial and aquatic sub-Antarctic biodiversity, ecology and geographic distribution still contain many gaps. Moreover, there is a fair amount of evidence that biodiversity of sub-Antarctic regions will be increasingly threatened by climate change. As the sub-Antarctic Islands are warming at an unprecedented rate, they are becoming increasingly vulnerable to invasions under a milder climate. Hence, these environments are excellent sentinels, acting as natural laboratories in which to study the synergisms between climate change and biological invasions. In this project, we aim to combine existing data enriched with long-term monitoring data and new investigations for terrestrial and aquatic biota to better understand the ecology and redistribution of the sub-Antarctic species, predict how these may change into the future, and develop mitigation measures to deal with impacts. Our proposed research efforts will continue improving the current knowledge of the mechanisms and factors driving the distribution and assemblages of species at local and regional scales at Crozet and Kerguelen Islands. We will focus on plants and invertebrates whose ecology, fitness and distribution are driven by the microclimatic characteristics of their habitats. Plants and invertebrates are often keystone or pioneer species structuring ecological networks. By linking the distribution of plants and invertebrates, we will be able to consider and reveal the cascading effects of changes of their ecological interactions. An exhaustive analysis of the effects of climatic changes and biological invasions on sub-Antarctic ecosystems must also combine ecological dynamics with the values conferred by human societies to this biodiversity, and the characterisation of the different mode of transmission of the biodiversity knowledge. Finally, by teasing apart the complexity of the biodiversity redistribution processes, and with the synthesis of knowledge gained with this application, we will be able to markedly improve the spatial planning for developing conservation strategies at the Crozet and Kerguelen Islands, both having the status of protected areas, and belonging to the UNESCO’s world heritage list.