Rare & Endangered - Spectacled Hare-wallaby
By Sandy Ingleby
Nature Australia, Volume 25, no 1:22
Despite its contraction in range, the Spectacled Hare-wallaby has fared well in comparison to other hare-wallabies.
At the time of European settlement in Australia large parts of the mainland and several offshore islands were inhabited by hare-wallabies (Lagorchestes and Lagostrophus spp.). These small macropods resembled European Hares to early scientists. They were similar in size, and were renowned for their speed and agility. John Gould was particularly impressed by the jumping ability of one that was chased by his dogs across the plains in South Australia during the 1840s. He wrote: "the animal had arrived within 20 feet before it observed me, when...instead of branching off to the right or left; it bounded clear over my head".
Five species of hare-wallabies have been described although one is only distantly related to the others (four Lagorchestes and one Lagostrophus). Of these two are now extinct, another two are endangered and only one, the Spectacled Hare-wallaby (Lagorchestes conspicillatus), remains widespread.
Like other members of their genus, Spectacled Hare-wallabies are nocturnal, spending the day in small squats or shallow burrows under grass tussocks or low shrubs. They are well adapted to arid or seasonally arid environments, being able to produce highly concentrated urine and having low metabolic rates. They are generally solitary, although several animals may be seen feeding together. Their diet consists predominantly of grass and herb foliage, seeds and fruit.
The Spectacled Hare-wallaby inhabits open forests, open woodlands, tall shrublands and hummock grasslands. It has a wide distribution, however its occurrence within this area is extremely patchy and there have been marked contractions in its range during the last 100 years. It is still common on Barrow Island, and occurs across large parts of tropical Northern Territory and Queensland. However, its range in southern Northern Territory has contracted northwards by over 200 kilometres during the last 50 years, and it is now rare in the Pilbara and Kimberley regions of Western Australia. Its range in Queensland does not seem to have altered greatly during the last century, although numbers in central Queensland have declined over the last 20 years.
The main factors responsible for the decline of Spectacled Hare- wallabies appear to be habitat alteration by introduced herbivores and fire, and predation by feral animals. However, the importance of these factors seems to have varied in different parts of their range. Cats were almost certainly responsible for their disappearance from Hermite Island, Western Australia, from 1912--1950, but they do not appear to have been a major factor elsewhere. The combined effects of rabbits, foxes and introduced stock may have pushed Spectacled Hare-wallabies to extinction in the MacDonnell Ranges, Northern Territory, whereas land degradation through overstocking with sheep and cattle, and inappropriate burning patterns, are believed to have been important in the Pilbara and Kimberley regions. The cessation of traditional Aboriginal burning practices may also have disadvantaged Spectacled Hare-wallabies, although burning patterns have changed over large parts of their range, not just the southern parts.
Despite its contraction in range, the Spectacled Hare-wallaby has fared well in comparison to other hare-wallabies. This is probably because it is not confined to arid and semi-arid areas of central Australia but also inhabits the tropical north. In the latter area it would not have been exposed to the factors that caused other hare-wallabies to virtually disappear from the mainland. Foxes, rabbits and sheep are generally absent from parts of northern Australia where Spectacled Hare-wallabies occur today, and few habitats have been extensively cleared as yet. Indeed many other 'medium-sized mammals' (those weighing between 150 grams and five kilograms) that were once widespread have disappeared from arid or semi-arid areas but persist in the wetter northern parts of their range.
The Spectacled Hare-wallaby was classed as 'common' in Queensland during the early 1980s. However, it is at risk on mainland Western Australia and a more accurate description of its status over much of Northern Territory and Queensland today is 'vulnerable' or 'potentially vulnerable'. Attempts to determine whether the species is stable or continuing to decline are made difficult by the fact that numbers fluctuate from year to year. Populations in critical areas need to be monitored over successive years to determine trends.
During the late 1980s and early 1990s another factor loomed as a possible threat to Spectacled Hare-wallabies in the Gulf region of the Northern Territory. This is one of the few areas of the Territory where this species is relatively common, and one of its prime habitats here is Lancewood (Acacia shirleyi) forest interspersed with Bullwoddy (Macropteranthes keckwickii) thickets. A proposal was made to log Lancewood forests throughout a large part of the Gulf region to produce wood veneer. Fortunately the project was abandoned for economic reasons. However it illustrated that, while Spectacled Hare-wallabies did not appear to be threatened in that area, the situation can change rapidly.
Currently, few habitats suitable for Spectacled Hare-wallabies are present on reserved land, and the few national parks or reserves where this species has been recorded (except for Barrow Island) contain only marginal habitat. There is clearly a need for more areas of suitable Spectacled Hare-wallaby habitat to be included in the reserve system, and for inappropriate land management practices in other areas where they occur to be discouraged. Given the tragic history of extinctions among the medium-sized mammals of Australia, every effort needs to be made to preserve those that remain.
Dr Sandy Ingleby completed her PhD on the ecology of Spectacled Hare-wallabies and Northern Nailtail wallabies.
Article provided courtesy of Nature Australia Magazine
http://www.natureaustraliamagazine.com.au/index.htm
Copyright © Australian Museum, 2003
