Thursday 28 May 2009

1-2pm, in FORESTRY LECTURE THEATRE, Forestry building 48

To what extent does post-mining rehabilitation on the Weipa bauxite plateau restore the bird habitat values of pre-mining native forest

Susan Gould, Fenner School of Environment and Society

Abstract

Rehabilitation is seen as a key strategy for minimising biodiversity losses. Although most rehabilitation strategies aim to provide habitat, they generally focus entirely on establishing vegetation. Successful vegetation establishment, however, does not necessarily provide habitat to the species most in need of habitat restoration. Improved understanding of faunal response to rehabilitation is required if rehabilitation techniques are to be improved and deliver the hoped for biodiversity outcomes. This study aimed to assess the extent to which post-mining rehabilitation on the Weipa bauxite plateau has restored the bird habitat values of the pre-mining native forest.

Bird assemblages, vegetation, and landscape functionality were compared between (a) Eucalyptus tetrodonta open forest reference sites representative of the pre-mining open forest; (b) two Eucalyptus tetrodonta tall woodland land units that are considered ecologically appropriate analogues for the post-mining landscapes; and (c) a chronosequence of post-mining rehabilitation sites..Observational data was collected on bird species composition and abundance, and mensurative data was collected on vegetation composition and structure. Landscape functionality was assessed using visual indicators of soil surface processes.

Bird species richness and mean bird abundance increased with rehabilitation age. Bird species composition changed with rehabilitation age and became more similar to native forest bird assemblages. However, significant differences remained in the composition of the bird assemblages and bird community structure between the oldest age class of mine rehabilitation and native forest reference land units. There were also significant differences in vegetation composition and structure between native forest reference land units and post-mining rehabilitation sites. Most importantly, framework plant species that dominate the native forest vegetation community occurred at significantly lower densities in mine rehabilitation sites than in native forest reference land units. Site detection rates of birds were strongly related to vegetation composition and structure.

It is concluded that post-mining rehabilitation on the Weipa bauxite plateau has so far resulted in habitat conversion rather than habitat restoration. Post-mining rehabilitation created new habitat for 20 bird species not sourced from the pre-mining native forest. It also provided partial habitat for 70% of the native forest birds, although their presence in the landscape remained dependent on access to native forest. Rehabilitation did not provide habitat for 30% of the native forest birds including sedentary foraging specialists. This study found that the species most sensitive to loss of forest / woodland habitat may be the last to return to rehabilitation if they return at all.      

Bio

Sue Gould is a PhD candidate in the Fenner School of Environment and Society, College of Medicine, Biology and Environment at the Australian National University. Sue is part of the WildCountry Research and Policy Hub directed by Professor Brendan Mackey. After graduating from Macquarie University with BSc (Hons) majoring in Land and Resource Management Sue worked for 9 years in catchment management. Sue is an external student based on the far north-west coast of Cape York Peninsula.

The Fenner School Seminar Series is held in the Forestry Lecture Theatre, Forestry Building 48, Linnaeus Way (comes off Daley Road), ANU (Acton) campus, ACT

The seminar will start at 13:00 and finish at 14:00