|Scientific Name:||Gymnobelideus leadbeateri|
|Species Authority:||McCoy, 1867|
|Red List Category & Criteria:||Endangered B1ab(iii) ver 3.1|
|Reviewer(s):||Lamoreux, J. & Hilton-Taylor, C. (Global Mammal Assessment Team)|
Listed as Endangered because it has an extent of occurrence that is less than 5,000 km2, its distribution is severely fragmented, and there is continuing decline in the extent and quality of its habitat.
|Previously published Red List assessments:||
|Range Description:||This species is endemic to Australia, where it has a limited distribution (<3,500 km²) near the western limit of Victoria's eastern highlands from 500-1,500 m asl. There is a small, isolated population that occupies swamp forest at Yellingbo Conservation Nature Reserve at around 80 m (Smith and Harley 2008).|
|Lower elevation limit (metres):||80|
|Upper elevation limit (metres):||1500|
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||There are about 200 individuals at Yellingbo, and the main population is estimated at around 2,000 mature individuals. There is predicted to be a decline of approximately 90% over the next 30 years due to loss of den trees and suitable nesting habitat (Smith and Lindenmayer 1992).|
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||Leadbeater's Possum is a nocturnal, arboreal species that spends its day in tree hollows. Its diet mainly consists of exudates from trees and to a lesser extent arthropods (Smith 1984).
Optimum habitat for Leadbeater's Possum is a regenerating or uneven-aged Ash forest with a dense understorey of Acacia trees and an ample supply of old hollow trees. The occurrence and quality of habitat is primarily determined by patterns of successional change and stand development resulting from disturbance, such as past wildfires and timber harvesting operations. Regrowth from the 1939 wildfires, combined with fire-killed remnants of mature forest, has provided abundant feeding and nesting habitat during the last 30 years.
Older aged and mixed aged forest containing live hollow-bearing trees also support populations of Leadbeater's Possum, although not in the same high densities that can be found in suitable regrowth forests. The role, however, of these suboptimal forests in the medium-term will be critical for conservation of the species. These forests are not subject to a rapid decline in habitat suitability that is predicted to occur in current high value habitat regrowth forests. Older aged forest and mixed aged forest with hollow-bearing trees and a low occurrence of wattles are defined as potentially optimum habitat because of their potential to become optimum in the short term (<30 years), as a result of natural or deliberate disturbance.
|Major Threat(s):||This species is heavily dependent on old trees, and fire-killed remnants that are rapidly decaying and falling over. Recruitment of suitable hollows, used for shelter and breeding, is very slow. The long-term viability of habitat in mature and mixed aged forests is threatened by wildfires and some timber harvesting practices. The species and its remnant habitat also are closely tied to a narrow set of climatic conditions that could be severely affected by global warming (Lindenmayer et al. 1991).|
Leadbeater's Possum occurs in a number of protected areas and is listed as a threatened species both nationally and within Victoria. A recovery plan for the species was prepared (Macfarlane et al. 1998), as well as several conservation strategies (e.g., Smith 1982; Smith et al. 1985; Macfarlane and Seebeck 1991; Lindenmayer et al. 1991; Lindenmayer and Possingham 1994), but these are now largely out of date. Populations of this species have been monitored over the last several years conducted by numerous volunteers and public awareness of the plight of this species is high (Smith and Harley 2008). Research into the effects of fire and ways to improve timber harvesting techniques are important.
The species’ dependence on tree hollows that resulted from burnt remnant trees from the 1939 fires has led to dire predictions about its population trend over the next 30 years as these trees continue to collapse. The use of nest boxes as a management tool that has received a lot of attention as one way to possibly ameliorate the imminent cavity shortage. Research in the central highlands suggests that nest boxes receive a low rate of occupancy and would be ineffective as a large-scale solution to the problem (Lindenmayer et al. 2003). This result, however, has been questioned as nest box occupancy rates are much higher at Yellingbo (Beyer and Goldingay 2006; Harley 2006). Although the habitats are very different between the Yellingbo outlier and the central highlands the discrepancy in occupancy rates is thought to have more to do with box dimensions and placement than the difference in location, thus leaving open the possibility of nest boxes as a useful management tool for the species (Beyer and Goldingay 2006; Harley 2006).
Approximately 31% of its Ash forest habitat is protected, while about 69% is allocated for timber production. Timber harvesting is obviously a major factor of any recovery plan for Leadbeater's Possum (Lindenmayer 1996). Large-scale clear-cutting and even-aged stand management is detrimental to the species, and there have been efforts to adopt harvest practices that are compatible with the conservation of the species. The preservation of more large trees with hollows and a dense habitat structure with an understorey of Acacias is essential (Smith and Lindenmayer 1992; Smith and Harley 2008). Recently management recommendations for timber harvesting for Leadbeater's Possum has become very sophisticated, including, for instance, detailed recommendations for post fire timber salvage that protects patches of tall trees (Lindenmayer and Ough 2006). Further research is needed into timber management practices, and much work will be required to have these implemented.
|Citation:||Menkhorst, P. 2008. Gymnobelideus leadbeateri. The IUCN Red List of Threatened Species 2008: e.T9564A13001448. http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T9564A13001448.en . Downloaded on 13 October 2015.|
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