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FERALS AT WALGA ROCK By B.M.J. HUSSEY Senior Project Officer, Land for Wildlife, Department Of Conservation and Land Management, LB 104, Bentley DC, WA 6983. Walga Rock is a granite this zone is more or less bounded monadnock alongside the Cue- by the ring road. Dalaranga Road, 46 km west of On 18 September 1999, 1 recorded Cue. It is one of a group of such introduced species on or immedi¬ granite hills rising from a flat ately adjacent to the rock, i.e. on plain which drains westwards to the Norrie Land System. Most the Sandford and ultimately the annual plants were already over, Murchison River. The site was of therefore this list is probably far significance to Aboriginal people, from complete. Nevertheless, it who decorated a cave with some gives some idea of the change very fine rock art. Europeans have which is occurring in natural also favoured it as a camping spot, communities, even in remote and currently it is promoted as a areas such as this. tourist destination. It is included within the Austin Downs station lease. FAUNA The site lies in the Eremaean Equus caballus, Horse. Three seen, Botanical Province, Austin Botan¬ pushing in among the shrubs to ical District, Upper Murchison graze the still-green ground Sub-region (Beard 1976). The herbage. Possibly domestic rather vegetation of the flats is acacia than feral. shrubland to open shrubland over Equus asinus, Donkey. Some sparse low shrubs and bunch grass hoofmarks which could have (Aristida contorta). However, since been donkey were noted. the rocks harvest water, a different vegetation survives Capra hircus, Goat. Small group of around them. The complex is two nannies, two kids, seen described as the Norrie Land camping and browsing on the System in the pastoral survey by rock itself. Curry ct al 1994. The soil slopes Ovis aries, Sheep. Three seen, gently away from the rock. Dense grazing on claypan grasses in shrubbery grows immediately gnammas high on rock. adjacent to the rock where Presumably domestic. drainage is concentrated, succeed¬ ed by low bunch grass on the Orycytolagus cuniculus, Rabbit. sandy pediment. At Walga Rock, Common around base of rock. 115 Mus musculus, House Mouse. CONVOLVULACEAE Numerous around the main camp Cuscuta epithymum, Lesser Dodder. site, and probably other bushy Widespread, abundant parasite on areas also. ground layer plants, including bunchgrass and annuals such as Vulpes vulpes, Fox. Tracks and scats common. In early evening, a fox Angianthus tomentosus. cub jumped up onto the bonnet of the vehicle, in order to POLYGONACEAE investigate whether the washing up still carried anything edible. Emex . australis, Doublegee. Common at all campsites. Rumex vesicarius, Ruby Dock. One FLORA dense infestation at main camp site, single plants scattered POACEAE elsewhere, along tracks and among A vena barbata, Wild Oats. bunch grass. Occasional at disturbed campsites, especially on rabbit dung piles. PR1MULACEAE Pentaschistis airoides, False Hair Grass. Abundant among bunch Anagallis arvensis var. caerulea, Blue grass. Pimpernel. Common under dense shrubbery. Vulpia myuros, Silver Grass. Occasional among bunch grass at water-gaining sites, close to rock SOLANACEAE and in washways. Solarium nigrum, Blackberry Nightshade. Common in dense shade under shrubs close to rock. ASTERACEAE Hypochaeris glabra, Flatweed. Common at edge of shrub patches. DISCUSSION Sonchus oleraceus, Sow Thistle. This rock has mostly bare Occasional in deep shade. gnammas and no herbfields, unlike similar granites in the BRASSICACEAE Wheatbelt. This sparsity of plants must be related to the aridity and Sisymbrium orientale, Indian Hedge the high rock temperatures which Mustard. Single plant noted in will be reached in summer since, fenced area around art site - even on grazed farmland granites, removed and destroyed after some low vegetative cover usually observation. remains on gnamma floors. However, it is noticeable here that CARYOPHYLLACEAE the hooves of sheep and goats Silene ?nocturna, Catchfly. have cracked the surface crust on Occasional at edge of shrub gnamma floors and that this leads patches. to wind erosion of the fragile soil 116 accumulation beneath. Macropod It is likely to be transported by feet do not have as drastic an vehicles, and to appear first at effect, therefore it is possible that, water-gaining sites along track in the hundred or so years since edges. pastoral settlement, the flora (and At the moment, a determined presumably fauna) in the spraying effort could control - gnammas has become severely even eliminate - Ruby Dock, depauperate. Evidence from scats while annual checkups could shows that in wetter seasons prevent the invasion of Paterson's rabbits also feed on the outcrop, Curse. However, since there is no and this must exacerbate the authority really responsible for degradation. the site, and everywhere there are Foxes must have had a severe only limited resources available effect on any small to medium for weed control, it is difficult to sized native mammals which once know how this could be achieved. occurred in the area, and also on Perhaps this example could be lizards and frogs - although it is presented to the body responsible possible that they have merely for implementing the State Weed replaced the dingo. Plan, with a request that a trust fund be set aside and a ‘flying Apart from the False Hair Grass, squad’ trained and then employed all the plants are likely to have to tackle such weed problems in been brought to the site by fauna, remote localities. either externally or internally. At the moment they are a relatively minor component of the flora. REFERENCES The greatest threat to the integrity of the site would appear BEARD, J.S. 1976. Vegetation Survey to be Ruby Dock and Paterson’s of Western Australia, Sheet 6, Curse (Echium plantagincum, Murchison. Uni WA Press, Perth. Boraginaceae), both of which are CURRY, P.J., PAYNE, A.L., highly invasive and totally alter LEIGHTON, K.A., HENN1G, P. and the character of the vegetation communities they infest. The BLOOD, D.A. 1994. An inventory latter does not yet occur here (nb: and condition survey of the as at date 18/09/1999) although Murchison River catchment, there is a large infestation at Western Australia. Tech. Bull. No Austin Downs station, 36 km east. 84. Dept, of Agriculture, Perth. 117