This species saw the most significant decline from 1930 to the 1990s, when their distribution was reduced by over half (de Tores et al., 2007). The quokka markedly declined in its abundance and distribution in the early 1930s, and this tendency has continued till today. Their presence on the mainland has declined to such an extent that they are only found in small groups in bushland surrounding Perth. The quokka is now listed as vulnerable in accordance with the IUCN criteria.