Do Koalas Phascolarctos cinereus use trees planted on farms? A case study from north-west New South Wales, Australia.

Abstract

Biodiversity benefits are routinely cited as an outcome of planting trees on farms but there has been too little information to properly substantiate such claims. This study is among the first to examine the use of plantings by arboreal mammals. We examined an important inland koala population and its use of farm revegetation to determine: (1) if koalas use planted trees; (2) patch characteristics correlated with use/non-use by koalas; and, (3) contextual characteristics correlated with use/non-use. Surveys of koala dung, also known as scats or faecal pellets, were conducted under trees in 19 plantings. Fourteen showed signs of koalas and their pellets were recorded under 16 of the 25 tree taxa examined. All sizes and ages of trees were used, including the youngest plantings (six years). Considerable koala activity occurred in the various Eucalyptus species, but some tree species were not used. Koalas made substantial use of inland ironbark species, which are not listed as ‘koala food trees’ in government policy documents. Proximity to potential source populations of koalas was the strongest predictor of a planting being used, but this was further improved by including the age of the planting. There is extensive public funding available for restoration and land care activities. This study demonstrates that certain trees rapidly provide koala habitat when planted on farms and that the first priority should be restoring sites in close proximity to known koala populations. Tree species used should include local recognized food trees, as well as ironbarks and non-eucalyptus species that offer shelter.