Overview, Critical Assessment, and Conservation Implications of Koala Distribution and Abundance

Abstract

Regional and national surveys provide a broadscale description of the koala's present distribution in Australia. A detailed understanding of its distribution is precluded, however, by past and continuing land clearing across large parts of the koala's range. Koala population density increased in some regions during the late 1800s and then declined dramatically in the early 1900s. The decline was associated with habitat loss, hunting, disease, fire, and drought. Declines are continuing in Queensland and New South Wales. In contrast, dense koala populations in habitat isolates in Victoria and South Australia are managed to reduce population size and browse damage. Current understanding of koala distribution and abundance suggests that the species does not meet Australian criteria as endangered or vulnerable fauna. Its conservation status needs to be reviewed, however, in light of the extensive land clearing in New South Wales and Queensland since the last (1980s) broadscale surveys. Consequently, we recommend that broadacre clearing be curtailed in New South Wales and Queensland and that regular, comprehensive, standardized, national koala surveys be undertaken. Given the fragmentation of koala habitat and regional differences in the status of the koala, we recommended that studies on regional variation in the koala be intensified and that koala ecology in fragmented and naturally restricted habitats be developed. More generally, the National Koala Conservation Strategy should be implemented.

Low-density koala (Phascolarctos cinereus) populations in the mulgalands of south-west Queensland. IV. Abundance and conservation status

“…For example, the NGO Australian Koala Foundation estimates that the national population is 45000-80000 (25-50000 in Queensland and 10-15000 in both New South Wales and Victoria (Sharp 1995). This contrasts sharply with other estimates, for example 170000 in Queensland alone (G. Gordon, Queensland National Parks and Wildlife Service, personal communication), up to 10000 in New South Wales , and 75000-130000 for the Strathbogie Plateau in Victoria (Melzer et al 2000). The uncertainty of population estimates is further illustrated by Phillips (2000), who estimated koala abundance for the Strathbogie Ranges by modelling population growth from a known history of introductions and an expected rate of increase.…”

“…The most significant threat to the long-term conservation of koalas is habitat loss, although drought, wildfire, disease, predation and vehicle strikes are also serious threats (Melzer et al 2000). Despite these threats and the level of uncertainty regarding the abundance of koalas, it has been suggested that conservation intervention should be taken now, since there is clear evidence of decline in some populations while the existence of other robust populations offers the possibility of a variety of creative solutions (Sherwin et al 2000).…”

“…Acacia-dominated communities) or have extremely low-density koala populations. Estimates of broadscale clearing of eucalypt woodland may overestimate koala habitat loss because they include eucalyptus communities beyond the natural range of the koala (Melzer et al 2000). However, in reality, the reduction in koala numbers due to habitat clearance may have been considerably higher because of the further fragmentation of habitat.…”

MHC class II diversity of koala (Phascolarctos cinereus) populations across their range

“…The survival of the koala (Phascolarctos cinereus), an iconic Australian folivorous marsupial, is threatened by habitat loss, population fragmentation, motor-vehicle strike, predation by dogs and disease (Jackson et al, 1999;Melzer et al, 2000;McAlpine et al, 2006;Griffith et al, 2013). Koalas are currently distributed in the eastern states of Australia with additional isolated populations in South Australia (Figure 1).…”

“…Koala populations from Queensland and New South Wales (NSW) have also not experienced any systematic translocation and, relative to their southern counterparts, have high microsatellite diversity (Houlden et al, 1996). Although many northern populations are genetically distinct, as identified in south-east Queensland and north-east NSW (Lee et al, 2009(Lee et al, , 2012, this may be attributed to anthropogenic-related fragmentation and decline in many of these populations (Melzer et al, 2000;Gordon et al, 2006;Lunney et al, 2009). Northern populations were therefore listed as 'vulnerable' in early 2012 under the Australian federal Environment Protection and Biodiversity Conservation (EPBC) Act 1999.…”