Incorporating habitat mapping into practical koala conservation on private lands
Lunney, D, Matthews, A, Moon, C & Ferrier, S 2000, Conservation Biology, vol. 14, no. 3, pp. 669-680.
Incorporating community and field surveys, this study mapped koala habitat in the Coffs Harbour shire at the scale required by planning authorities, with a focus on identifying remnant habitat on private land. Community survey respondents reported a total of 3309 koala sightings. Faecal pellet and field surveys were carried out at 119 sites, 37 (31%) of which had been used by koalas.
Koala locations reported by survey respondents were collated and overlaid with a vegetation community map. Koala density of each vegetation unit was calculated and ranked accordingly. Field surveys examining community composition, tree species and geology provided an objective evaluation of habitat preference, with sites selected from each of the vegetation units. Habitat survey results were merged to develop a combined rank for each vegetation map unit. Findings from community surveys showed a concentration of sightings along a coastal strip (20km x 15km). Of the 1570 locations of koalas, the vast majority (82%) were on private land, with only 16.5% in either state forests or national parks. No koalas were sighted during field surveys; however, koala scats were observed in half of the vegetation units sampled. Scat data showed that 32 different tree species were used by koalas, of which Eucalyptus microcorys was preferred most, especially on quaternary deposits. Other tree species that were regularly used were often found in association with E. microcorys. Scats were observed more frequently than expected on southern and eastern aspects and in gullies – a likely reflection of the distribution of preferred vegetation types.
A high degree of overlap was detected after community and field survey data were overlaid. Sixty per cent of the area identified as high-density habitat by the community survey was distinguished as prime habitat from the field survey. This finding accords with other research that shows that E. microcorys is most common in high-density areas in the southeast sector of the shire. Preferred habitat was found to be largely fragmented, with developed land enveloping remnant bushland patches. As high-quality koala habitat is correlated with flat, fertile land, it is also valuable land for development. A significant proportion (78.3%) of vegetation that remained on private land was identified as koala habitat and as such, these areas must be incorporated into local planning frameworks.
This study demonstrates the importance of detailed vegetation mapping and its role in identifying valuable habitat outside of the reserve system. The procedure for mapping koala habitat outlined by this study enables planners to identify priority conservation areas on private land within the framework of a shire, thus allowing for their incorporation into environmental protection zones. Indeed, the most notable outcome of this study was the integration of the koala habitat map into the Coffs Harbour local environmental plan.
Summarised by Julian Radford-Smith
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