The terrestrial biodiversity of these sub-Antarctic islands, while relatively limited in numbers (22 species of flowering plants on Kerguelen and 16 species on Crozet), is nonetheless fairly rich for this environment and the rate of endemism can be high. For example, 55% of the invertebrate species of Crozet are endemic to this archipelago.

The Kerguelen and Crozet archipelago is also rich in pelagic species (crustaceans, squid, and fish) and as a result have important populations of marine mammals such as Southern Elephant Seals (Mirounga leonina), Antarctic Fur Seals (Arctocephalus gazella), Subantarctic Fur Seals (Arctocephalus tropicalis), also known as Amsterdam Island Fur Seals, as well as Commerson’s Dolphins (Cephalorhynchus commersonii).

However, the greatest wealth of these sub-Antarctic islands, particularly the Crozet archipelago, rests in its marine bird populations (between 15 and 35 different species). Crozet hosts four dominant species of penguins, petrels, albatrosses, prions, cormorants, skuas, gulls, terns, Cape Petrels (Daption capense), and others. Amsterdam Island has the largest colony of Atlantic Yellow-nosed Albatrosses (Thalassarche chlororhynchos) in the world and the only population of Amsterdam Albatrosses (Diomedea amsterdamensis). Finally, Adélie Land has large colonies of Adélie Penguins (Pygoscelis adeliae) and Emperor Penguins (Aptenodytes forsteri), the only marine birds found solely on the Antarctic continent and the Antarctic ice shelf.

In addition, biodiversity protection is an important concern in these territories. Crozet was designated as a “national park refuge for certain species of birds and mammals” since 1938, the area of the White-chinned Petrel (Procellaria aequinoctialis) colony are protected since 1989, and the Terres australes françaises (Southern French Territories) nature reserve the largest in France by surface area , was created in 2006. In light of various provisions for the protection of biodiversity in Antarctica including the Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR), the Treaty of Washington, and the Madrid Protocol the whole of Adélie Land can be considered a protected area. Read more