Biodiversity publications archive

Refugia for biological diversity in arid and semi-arid Australia

Biodiversity Series, Paper No. 4
S.R. Morton, J. Short and R.D. Barker, with an Appendix by G.F. Griffin and G. Pearce
Biodiversity Unit
Department of the Environment, Sport and Territories, 1995

10. Refugia in Western Australia (continued)

10.9. Reference number WA9

Refuge area: Cape Range caves and gorges

Biogeographic region: Carnarvon

Type of refuge: Cave system and gorge

Lat./Long. 22°07’S / 113°57’E

Quality of refuge: Extremely significant (7)

Area (km²): <1,000

Chief refuge value

Relict species of fish and invertebrates in cave systems; ANZECC-listed species and relict plant species in gorges.

General description

More than 400 caves and other karst features6. Divided into two major categories: caves of the range itself are often humid but contain little standing water; caverns and voids of the foothills and coastal plains contain fresh to saline water. There are rugged ranges with numerous gorges, and permanent water is impounded in Yardie Creek.

ANZECC-listed species

Black-footed rock-wallaby Petrogale lateralis (V) in gorges of Cape Range. A significant rookery for Green Turtles Chelonia mydas (V) exists on north-west coast of North-West Cape. Hawksbill Eretmochelys imbricata (V) and loggerhead turtles Caretta caretta (E) nest in small numbers on North-west Cape10.

Regional endemics

Invertebrates: 56% of land snails are endemic (nine camaenid and one pupillid species) are endemic9. Many troglobites are also endemic (see below).

Plants: There are 12 endemic taxa and six largely confined to the peninsula from 630 taxa13.

Relict species

Invertebrates: Thirty-eight species of troglobites, involving 28 families and 30 genera (10 endemic), plus a large number of species of troglophiles have been collected from Cape Range (these estimates include the Barrow Island fauna). The troglobites include pseudoscorpions (the genera Tyrannochthonius and Hyella), a schizomide arachnid (Draculoides vinei), an opilionide arachnid (an undescribed genus), species from six families of spiders (Desidae, undescribed genus; Ctenidae, undescribed genus; Miturgidae, undescribed genus; Symphytognathidae, Anapistula sp.; Theridiidae, Steatoda spp.; Linyphiidae, Dunedinia occidentalis and Chthiononetes tenuis), crustaceans from the groups Thermosbaenacea (Halosbaena tulki), Amphipoda (an undescribed eriopisid genus), Isopoda (undescribed genera) and Decapoda (Stygiocaris lancifera and S. stylifera), millipedes (Stygiochiropus communis, S. sympatricus, S. isolatus, and Boreohesperus capensis), a cockroach (Nocticola flabella), bugs (including Phaconeura proserpina), and undescribed Orthoptera1-8. The affinities of the fauna are varied, but a large element of the terrestrial troglobites is derived from the humid tropics and "is relictual from times when humid forest covered this region"1.

The snails on Cape Range appear to be relicts of formerly more widespread populations. The non-marine fauna consists of two species of aquatic prosobranch gastropods and 16 species of terrestrial pulmonates . Nine species of camaenid snails (in Rhagada, Quistrachia, and three undescribed genera) and one pupillid (Pupoides sp.) are endemic; 56% of the land snails in the area are endemic. Some species have a cavernicolous existence at Cape Range, but occupy a greater diversity of habitats in more humid areas9.

Fish: The blind gudgeon Milyeringa veritas and the blind cave eel Ophisternon candidum are the only vertebrate animals known from Australasia that are restricted to either caves or groundwater; they are declared as threatened fauna under the Western Australian Wildlife Conservation Act7.

Plants: Millstream palm Livistona alfredii at the top of the Yardie Creek system13.

Other significant species

Fringing vegetation of Typha domingensis and Schoenoplectus litoralis along Yardie Creek, including Banksia victoria and Ipomoea yardiiensis13.

Key threats

High tourist use of Cape Range National Park exceeding management capability. Key threats to troglobite fauna come from changes to ground water levels and mining of limestone (most caves lie within a Temporary Limestone Reserve). Unplanned road building within the area also may alter water levels by causing sediments and nutrients to leak into caves. The fauna is potentially threatened by the development of Exmouth as a residential and tourist centre (by contamination of groundwater and surrounding waters by excessive nutrients, heavy metal or hydrocarbons). The watertable of North-west Cape Peninsula may be declining and becoming more saline1, 3.

Land tenure

Cape Range National Park.

Key references

1. Humphreys (1993)

2. Humphreys (1990)

3. Humphreys and Blyth (1994)

4. Harvey (1991); Harvey et al. (1993)

5. Humphreys et al. (1989)

6. Shear (1992); Humphreys and Shear (1993)

7. Knott (1993)

8. Humphreys and Adams (1991)

9. Slack-Smith (1993)

10. Burbidge et al. (1974)

11. Jaensch and Lane (1993)

12. Prince (pers. comm.)

13. Keighery and Gibson (1993)