Tree species preferences of a koala population inhabiting a small area of
forest and woodland in the Campbelltown area, south-west of Sydney, were
investigated over a two-year period. In total, 2499 trees from 45 independent
field sites were assessed, with tree species preferences determined on the
basis of a comparative analysis of proportional data relating to the
presence/absence of koala faecal pellets. The results established that
grey gum (Eucalyptus punctata) and blue-leaved
stringybark (E. agglomerata) were most preferred by
koalas in the study area, but only when growing on shale-based substrates. The
preferential utilisation of E. punctata and
E. agglomerata on substrates derived from shales,
compared with that recorded for the same species on sandstones, suggests that
their use by koalas was influenced by differences in nutrient status between
substrates. Regression analyses further identified a trend for use of at least
one of the preferred species (E. punctata) to be more
commonly associated with larger trees. Results are discussed in terms of their
relevance to issues of resource availability and the need to reconsider, by
way of a hierarchical approach, the use of food trees by koalas generally. The
presence of E. punctata and
E. agglomerata and their occurrence in conjunction with
shale-based substrates are considered to be important limiting factors
affecting the present-day distribution and abundance of koalas in the
Campbelltown area.
Can variation in seed removal patterns of Neotropical pioneer tree species be explained by local ant community composition?
