Use of sap trees by the yellow-bellied glider near Maryborough in south-east Queensland

Abstract

Identifying the tree species used in sap feeding by the yellow-bellied glider (Petaurus australis) and describing the pattern of use of these trees is fundamental to forest management in eastern and southern Australia. We conducted surveys at 74 sites across 17 000 ha in St Mary State Forest near Maryborough in south-east Queensland, during five visits over a 2-year period. We identified sap-feeding incisions of gliders on 194 trees (2% of all trees) at 47 of our survey sites, including five trees recruited as sap trees during our monitoring period. Five tree species were involved: Corymbia citriodora (100 trees at 26 sites), Eucalyptus longirostrata (73 trees at 19 sites), Eucalyptus moluccana (17 trees at 6 sites), Eucalyptus tereticornis (3 trees at 3 sites), and Angophora leiocarpa (1 tree). Of these trees, E. longirostrata was used much more than expected on the basis of its abundance in the forest. Active glider incisions were observed on 95 of the sap trees (49% of total) during the monitoring period. During our first visit, 66 sap trees showed no evidence of current or recent use (within the previous month). By the fifth visit, there were still 44 sap trees (23% of all sap trees) that showed no evidence of recent use during any visit. Approximately 40% of sap tree observations were of trees with fewer than five recently active incisions, which is currently the threshold number of incisions for tree retention during logging operations in Queensland. We used Poisson regression to assess the influence of climatic and habitat variables on the abundance of active incisions at sites with sap trees. Three variables had a significant influence on the abundance of active incisions at a site: flowering, site index (a measure of productivity) and density of ringbarked trees. Our results confirm the importance of a small number of forest trees in sap feeding and recommendations are provided to enhance prescriptions for effective management of sap food resources of yellow-bellied gliders in south-east Queensland.