Reintroduction ecology of mala (Lagorchestes hirsutus) and merrnine (Lagostrophus fasciatus) at Shark Bay, Western Australia.

The transfer of threatened animals from one location to another in order to benefit the species is a technique frequently used by animal conservation managers. However, very few of these relocations have experimentally assessed the relative merits and disadvantages of commonly used release techniques. Two species of hare-wallaby, mala (Lagorchestes hirsutus) and merrnine (Lagostrophus fasciatus), were reintroduced in August 2001 onto Peron Peninsula in Western Australia. These threatened species were reintroduced using two release strategies (soft versus hard release), and their subsequent movements and body condition were monitored using radio-telemetry and trapping. Prior to this study, little information was available on the ecology of either species, and no data were available to show how these animals reacted to reintroduction attempts. Results from the experimental reintroduction showed that the method of release did not affect site fidelity, body condition or survival of either species. Once settled post-reintroduction, both mala and merrnine regularly alternated between diurnal shelters, but continued to reuse some refuges over the course of the study. The hare-wallabies exhibited preferences for certain vegetation species and characteristics in which their diurnal shelters were located. Importantly, both species also showed flexibility in utilizing a range of vegetation types and adjusting this shelter to their requirements by altering unsuitable refugia characteristics. Mala and merrnine home ranges were generally smaller than anticipated and exhibited no difference in size between sexes. These results indicate that the quality and productivity of available vegetation was sufficient for the energetic requirements of the small reintroduced populations. The body condition results demonstrate that the reintroduced animals, bred and raised in captivity, were able to physically adapt to their new environment and survive on the wild food sources. In addition, the presence of pouch young in all female harewallabies in autumn provides further evidence to suggest that the overall health of the animals was sufficient to allow sexual maturation and breeding success. Intestinal parasite studies found nematodes and protozoans to be present in reintroduced hare-wallabies, but these populations were unlikely to adversely affect health. This study has shown that hare-wallabies are robust and versatile animals that have the ability to cope with a range of vegetation communities, competition from exotic species and a level of habitat alteration. The implication of this finding is that these hare-wallaby species should maintain healthy body condition and breeding ability when reintroduced into a range of historically disturbed environments. However, although the hare-wallabies demonstrated an ability to adapt to a new environment and survive under extreme environmental conditions, they were not able to survive the level of predation applied by the remaining feral cats. Future reintroductions must take into account the severe impact of feral cats on small macropods, and implement appropriate management strategies to combat this factor. The knowledge gained by this study can now be used to enable conservation agencies and wildlife managers to implement improved and effective management strategies for the conservation of these and perhaps other similar macropods in arid and semi-arid environments.