Threatened Plants of Shark Bay

At least 53 plant species are endemic to the Shark Bay region. Their restricted range means that some species are extremely rare. Two plants are nationally classified as threatened species, while many more are considered ‘priority’ species. More study is needed to determine whether these ‘priority’ species should also be considered rare, and in need of special protection.

Endangered and vulnerable species

Shark Bay World Heritage Area is home to two plant species listed as rare under Western Australian law: the small dragon orchid Caladenia barbarella (previously Drakonorchis barbarella) and Beard’s mallee, Eucalyptus beardiana. Under federal law Beard’s mallee is listed as an endangered species, while the dragon orchid is listed as vulnerable to extinction.

The small dragon orchid is a delicate plant growing just 8–25 cm high. Its flowers, which appear in August and September, have curved green-white petals marked down the centre with a bright burgundy stripe. In Shark Bay it occurs in the Zuytdorp Nature Reserve, where a population of about 50 plants has been recorded from a seasonally wet claypan.

For more information about Beard’s mallee, go here. You can also learn more about Shark Bay’s endangered inhabitants here.

Priority species requiring further study

At least 56 species in the Shark Bay World Heritage Area are ‘priority’ species. These are species that are known from only a few collections, or a few sites. It’s possible that they are rare or threatened, but they can’t be listed as rare until further study is done. There are five priority categories:

Small dragon orchid - Caladenia barbarella

Small dragon orchid (Caladenia barbarella)

  • Priority 1, 2 and 3 species are ranked in order of urgency for study and evaluation of their conservation status. There are ten Priority 1, twenty Priority 2 and twenty Priority 3 species in the Shark Bay World Heritage Area. These include the endemic Acacia drepanophylla, Shark Bay grevillea (Grevillea rogersoniana) and Macarthuria intricata (a small, intricately branched shrub), as well as golden lambstail (Physopsis chrysophylla) and Shark Bay featherflower (Verticordia cooloomia). Some of these priority species occur in Shark Bay’s unique ‘tree heath’.
  • Priority 4 species are adequately known, and are rare but not threatened. They require monitoring every 5–10 years to check their status. There are six Priority 4 species in Shark Bay, including Jacksonia dendrospinosa.
  • Priority 5 species are not threatened but depend on specific conservation programs. If these programs were to end, the species would become threatened within five years. No species in Shark Bay has Priority 5 listing.

There is still much to be learned about the plants of Shark Bay. It is possible that many other species, as yet undescribed, could have conservation significance.

For more information about Western Australian plants check out the West Australian Herbarium’s FloraBase.

Beard's mallee - Eucalyptus beardiana

Beard's mallee (Eucalyptus beardiana)