Biodiversity Series, Paper No. 4
S.R. Morton, J. Short and R.D. Barker, with an Appendix by G.F. Griffin and G. Pearce
Department of the Environment, Sport and Territories, 1995
6. Foci of biological diversity in the Northern Territory (continued)
6.7. MacDonnell Ranges
Cattle grazing, tourism, Aboriginal use.
National Parks and Nature Reserves
West MacDonnells National Park; Finke Gorge National Park; Watarrka (Kings Canyon) National Park; Trephina Gorge National Park; N'Dhala Gorge Nature Park; Ruby Gap Nature Park and Arltunga Historic Reserve.
A major problem is exotic vertebrates, primarily horses, rabbits, donkeys, foxes, and feral cats. Rabbits may be a particular problem for relict populations of brush-tailed possums Trichosurus vulpecula (Gibson et al. 1992). Tourist impacts are likely to escalate, leading to possible pollution of the few permanent waterholes with consequent impact on invertebrate and fish fauna. Exotic plants such as tamarisk, buffel grass, and couch are in danger of spreading (Latz 1982; Gibson and Cole 1993, p. 70). Fire represents a risk to mature hummock grass communities. In the Arltunga Historical Reserve, rabbits, grazing stock (feral donkeys and horses) and cats are listed as management problems; 22 introduced plant species are listed, mainly from the mining era (Service Enterprises 1980). Latz et al. 1981 noted fire, feral animals (cattle, camels, horses, rabbits), erosion and uncontrolled visitor use as issues in the George Gill Range.
Gorges of the Ranges support relict plants and aquatic fauna that are susceptible to disturbance by grazing stock seeking water. Latz (1995) suggested that some plant species could have been exterminated early during European settlement, and Davis (1995) noted that the fish assemblage would be susceptible to introduced species such as trout, carp or mosquitofish.
Black-footed rock-wallabies continue to decline elsewhere in arid Australia, for reasons that remain unclear (but probably introduced predators; Kinnear et al. 1988; Copley et al. 1989; Pearson 1992), and the MacDonnell Ranges populations may become relictual.
Mammals: The black-footed rock-wallaby Petrogale lateralis (V) is present in both western and eastern MacDonnell Ranges, was reported from Illamurta Springs Conservation Reserve in James Range in 1975, and from the Kings Canyon area (Millington et al. 1980; Latz et al. 1981; Latz 1982; Gibson and Cole 1993; Gibson et al. 1992).
Presence of central rock-rat Zyzomys pedunculatus (E) was suspected in the eastern Chewings Range because of characteristic gnawing pattern on cycad seeds (Fleming et al. 1984), but more recent searches have failed to locate this species (Wurst 1990).
Birds: Records of malleefowl Leipoa ocellata (E) from a number of localities in central Australia, including near Hermannsburg (Kimber 1985). Alexandra's parrot Polytelis alexandrae (V) recorded in the past but not by Gibson and Cole (1993, p. 57).
Plants: The cabbage palm Livistona mariae (V) from Palm Valley. Ricinocarpos gloria-medii, "glory-of-the-centre" (V) is known from Simpsons Gap National Park, Trephina Gorge National Park, and N'Dhala Gorge Nature Park and three other populations (Leigh et al. 1984, p. 199; Soos et al. 1987); it occurs in deep gullies or well shaded areas of south-facing slopes. Acacia undoolyana (V) occurs in the eastern MacDonnell Ranges (N'Dhala Gorge) (Latz et al. 1989; see also Soos et al. 1987). Fire is a serious threat to the latter two species (Soos et al. 1987).
Species that are regionally endemic
Vertebrates: No extant mammals or birds appear confined to this Region. The blind snake Ramphotyphlops centralis is endemic (Cogger 1992).
Invertebrates: The dragonfly Hemicordulia flava is confined to the Region (Watson et al. 1991, pp. 44-6). Solem's (1993) studies of camaenid land-snails reveal an extraordinary radiation in the MacDonnell Ranges, with many of the species apparently being confined to tiny ranges. The following species are endemic to the Region: Pleuroxia adcockiana, Granulomelon arcigerens (only from Glen Helen Gorge), G. gilleni (from the Strangways Range), G. grandituberculatum (Harts Range), G. acerbum (Eastern MacDonnells), Sinumelon bednalli (immediately to the east of Alice Springs), S. expositum (Western MacDonnells), S. gillensis (springs of the George Gill Range), Basedowena squamulosa (only from Palm Valley and Areyonga), Semotrachia hortulana (Hale River basin), S. strangwayana (Strangway Range), S. setigera, S. rossana (Eastern MacDonnells near Ross River homestead), S. bensteadana (vicinity of N'Dhala Gorge), S. jessieana (only from Jessie Gap), S. emilia (only from Emily Gap), S. euzyga (immediate vicinity of Alice Springs), S. caupona (immediate vicinity of Alice Springs), S. runutjirbana (Simpsons Gap), S. filixiana (Fenn Gap), S. winneckeana (Spencer Gorge and Ellery Creek Big Hole), S. elleryi (Serpentine Gorge, Ellery Creek Big Hole and the Ellery-Finke junction), S. esau (Finke River, Palm Valley and Palmer River), S. illarana (Illara Waterhole), S. hughana (two locations in the James Range), S. bagoti (southern face of the George Gill Range), Dirutrachia sublevata (Harts Range), Vidulomelon wattii (Harts Range), and Divellomelon hillieri (Palm Valley).
Plants: Among the best known is Livistona mariae of Palm Valley and Finke Gorge. This species appears to be holding its population size at around 3,000 individuals (Latz 1975). Many other species are endemic; see the section on Relict populations below, as well as Latz et al. (1981), Latz (1982), and Fleming et al. (1984).
The presence of relict species in the MacDonnell Ranges has been long known (Keast 1959; Chippendale 1963; Maconochie 1981; Leach et al. 1992; Latz 1995). For example, Latz et al. (1981) wrote that the George Gill Ranges were "botanically the most important area in Central Australia, containing 578 plant species and representing one-third of the Central Australian flora". They noted that 10% of the species were rare or relict, and five were known from nowhere else. The relicts mentioned were Hydrocotyle larapinta, Ampeara sp., Goodenia sp., Ixiolaena sp., Ricinocarpos sp., Psilotum nudum, Cyclosorus interruptus, Polystichum proliferum, Ottelia ovalifolia, Polygonum salicifolium, Schoenus falcatus, Vallisneria spiralis, Lindsaea ensifolia, and Mirbelia ramulosa.
The central Australian plants have been examined in some detail, and the following treatment is summarised from Leach et al. (1992) and Latz (1995). Latz (1995) noted that one group of plants appears to have been isolated for long periods and so have speciated; another group consists of species which occur in the most mesic areas of the Ranges and have much larger sister populations in coastal or near-coastal areas of Australia; Latz suggested that some of these species could well have arrived in central Australia recently as seeds carried by migratory birds. Finally, there are species with disjunct populations but which are not restricted to sheltered areas of the Ranges. However, Latz (1995) does not specify which species fall into these categories, and so we are forced to list them all here rather than separating them into endemics, relicts, and significant species as we would wish. Despite the lack of this detail, Latz's list is compelling evidence of the extent to which the MacDonnell Ranges Region possesses an extraordinary flora: Acacia calcicola; Adiantum capillus-veneris; Adiantum hispidulum; Agrostis avenacea; Alectryon oleifolius; Anacampseros australiana; Arthropodium strictum; Baumea arthrophylla; Bulboschoenus caldwellii; Bothriochloa bladhii; Bulbostylis pyriformis; Caesia chlorantha; Calotis cuneifolia; Carex fascicularis; Centipeda cunninghamii; Chenopodium desertorum ssp. anidiophyllum; Christella dentata; Chthonocephalus pseudevax; Clematis microphylla; Convolvulus remotus; Corynotheca licrota; Cratystylis sp.; Cyclosorus interruptus; Cymbopogon refractus; Cynanchum pedunculatum; Cynoglossum australe; Cyperus exaltatus; Cyperus laevigatus; Cyperus polystachyos; Dendrophthoe odontocalyx; Dicranopteris linearis; Diplachne parviflora; Dipteracanthus australasicus ssp. australasicus; Doodia caudata; Einadia nutans ssp. nutans; Elatine gratioloides; Eleocharis geniculata; Eleocharis pusilla; Eleocharis setifolia; Eragrostis sterilis; Eragrostis lacunaria; Eriocaulon cinereum; Eucalyptus orbifolia; Eucalyptus thozetiana; Euchiton sphaericus; Ficus platypoda var. minor; Fimbristytis eremophila; Fimbristylis rara; Fimbristylis sieberiana; Flueggia virosa; Gnaphalium sphaericum; Goodenia grandiflora; Gossypium sturtianum; Grevillea albiflora; Hibiscus sturtii var. sturtii; Histiopteris incisa; Imperata cylindrica; Iphigenia indica; Isoëtes muelleri; Juncus aridicola; Juncus continuus; Juncus kraussii; Leucopogon sonderensis; Lindsaea ensifolia; Livistona mariae; Lomandra patens; Macrozamia macdonnellii; Maireana brevifolia; Maireana pentatropis; Maireana sedifolia; Mirbelia ramulosa; Najas marina; Nephrolepis arida; Nymphoides indica; Olearia xerophila; Ophioglossum lusitanicum; Ottelia ovalifolia; Oxalis radicosa; Pachycornia triandra; Pandorea doratoxylon; Persicaria decipiens; Persicaria lapathifolia; Pityrodia loricata; Plagiobothrys plurisepalus; Plumbago zeylandica; Poranthera microphylla; Poranthera triandra; Prostanthera striatiflora; Psilotum nudum; Pteris tremula; Radyera farragei; Rhagodia parabolica; Rhodanthe laevis; Schizachyrium pseudeulalia; Schoenus falcatus; Sclerolaena bicornis; Solanum ferocissimum; Solanum petrophilum; Spartothamnella puberula; Stemodia viscosa; Stipa scabra ssp. scabra; Stipa trichophylla; Swainsona colutoides; Swainsona disjuncta; Tinospora smilacea; Trema tomentosa; Tricoryne elatior; Triglochin hexagona; Velleia glabrata; Vernonia cinerea; Wurmbea centralis; Zornia chaetophora; Zornia muriculata.
The cypress pine Callitris glaucophylla may represent a species restricted to dissected country by fire (Bowman and Latz 1993).
Brushtail possums Trichosurus vulpecula were originally widespread in central Australia but have declined to rarity. Today the species is known only from seven sites in the Western MacDonnell Ranges and one in the Eastern (Kerle et al. 1992); it also occurs at one site in the Central Ranges Region. Possums are associated with creek systems near to the ranges or with gorges in the ranges (Gibson and Cole 1993).
The great desert skink Egernia kintorei (Cogger et al. 1993, pp. 88-90) has not been recorded since 1936 in the Western MacDonnell Ranges (Gibson and Cole 1993, p. 84).
A distinctive form of the frog Litoria caerulea is confined in the MacDonnell Ranges Region to major, permanent rockholes in the ranges where it survives in cracks and crevices of rock faces adjacent to the water (Gibson and Cole 1993).
Relict streams in the George Gill Range "represent unique aquatic communities of both ecological and evolutionary importance in the arid zone" (Davis et al. 1993, p. 483). The key factor is the presence of at least six sheltered gorges which contain permanent or near-permanent springs and seepage areas. A small proportion of the fauna appears to be a relictual fauna, as exemplified by the water penny Sclerocyphon fuscus. Dragonflies such as Hemicordulia flava are confined to such areas. The conservation status of these streams, and of the gorges of the Western MacDonnell Ranges, is extremely high (Davis et al. 1993; Fleming 1993).
It is almost certain that many species of terrestrial invertebrates represent relictual populations, but as Yen (1995) has pointed out the baseline information on almost all invertebrate groups is so poor that it is impossible to write about the topic unambiguously. An example of a species that is probably relictual is the earthworm Acanthodrilus eremius, described 100 years ago but not seen since (Yen 1995).
Other significant populations
The herpetofauna of the West MacDonnell Ranges is one of the richest in the arid zone, but no species is classified as rare or endangered (Gibson and Cole 1993, p. 53). Nevertheless, nine species have not been recorded since 1936 or earlier. Many species of reptiles reach their range limits in the West MacDonnells (Gibson and Cole 1993, p. 56).
Bird species of regional significance include the peregrine falcon Falco peregrinus, bush thick-knee Burhinus grallarius, spinifex bird Eremiornis carteri and redthroat Sericornis brunneus (Gibson et al. 1992; Gibson and Cole 1993). Generally, however, the avifauna is typical of other inland ranges. There are discrete populations of red-tailed black cockatoos Calyptorhynchus magnificus, and several species reach range limits (Gibson and Cole 1993, p. 58).
The Finke River Headwater Gorges System is listed as significant by Fleming (1993). Ten species of fish occur. All but one species are widespread, and none is regarded as endangered in Australia (Michaelis 1985). However, the Finke River hardyhead Craterocephalus centralis is restricted to the Finke River basin, and the permanent waterholes of the Gorges are probably the major source from which repopulation downstream occurs after dry periods. The fish fauna of the Western MacDonnell Ranges is considered regionally significant because some waterholes have a complete suite of species (Larson and Martin 1989). As noted above, the aquatic invertebrate communities are also of high conservation significance (Davis et al. 1993).