|
| |
Kangaroo species of the month
- The north-east Queensland Rock-wallabies are diverse
and comprise a number of species that are described as parapatric
(not-overlapping in distribution) and cryptic (not obvious to tell
apart). Three species - the
Allied
Rock-wallaby (Petrogale assimilis), the
Mareeba Rock-wallaby (P.
mareeba) and
Sharman's
Rock-wallaby (P. sharmani) - inhabit the ranges between Airlie
Beach and Cairns. A quick inspection of picture-sharing web sites shows that
the Mareeba Rock-wallaby is amongst the most photographed of the macropods.
This is not surprising as there are several well-habituated populations in
one of the most popular regions of Australia for domestic and international
tourists alike.
 |
- A significant part of the habituation process is hand-feeding by
tourists at some sites. Food supplementation may be an interference in the
natural population dynamics of a species with a benign or caring motive but
detrimental consequences in the long-term. Wildlife Tourism Australia offers
a well-considered policy on this issue -
Tourist-wildlife Interactions. The policy concludes "In summary,
interactions between tourists and wildlife can be valuable in fostering
concern for wildlife among tourists, and provide much pleasure. However such
opportunities need to be provided in such a way as to minimise negative
effects on wild animals and ecosystems. " In the case of the Mareeba
Rock-wallabies at 'Granite Gorge', daily provisioning by tourists has
affected behaviour but not body condition relative to nearby colonies of
wallabies reliant on a natural diet. The provisioned wallabies are more
aggressive towards each other but also allo-groom (one individual grooming
another) more. So there is both heightened competition (likely for the food
supplements) and forms of conciliatory behaviour. This tension may explain
why the hand-fed wallabies have not become 'fat'.
- Whether you view these Rock-wallabies at a site of
habituated individuals or chance upon them in more wild circumstances,
how do you know which species you are viewing? From their morphology (body
appearance) you can be excused for being confused - all three look much the
same. The species differences are subtle and found in their chromosomes
which differ in number and/or shape (20 for both the Allied and Sharman's
Rock-wallabies and 18 for the Mareeba Rock-wallaby). The best clue is to
take out your GPS or map and confirm your location. South of Townsville and
west out to Hughenden and north up to Croydon is the domain of the Allied
Rock-wallaby. Sharman's Rock-wallaby is less dispersed in a tight cluster
north-west of Townsville bounded by the Star River in the south and the
Burdekin River to the north and west. Between the Herbert and Mitchell
Rivers to the south and west of Cairns you are in Mareeba Rock-wallaby
country.
 |
Hodgson AJ, Marsh H, Corkeron PJ (2004) Provisioning by
tourists affects the behaviour but not the body condition of Mareeba
rock-wallabies (Petrogale mareeba). Wildlife Research
31, 451-456.
Eldridge MDB, Johnson PM, Hensler P, Holden
JK, Close RL (2008) The distribution of three parapatric, cryptic species of
rock-wallaby (Petrogale) in north-east Queensland: P. assimilis, P.
mareeba and P. sharmani. Australian Mammalogy 30,
37-42.
|
