Long-term trends in avifaunal recolonisation of rehabilitated bauxite mines in the jarrah forest of south-western Australia

Alcoa of Australia Limited rehabilitates areas in the jarrah forest of south-western Australia following bauxite mining. One of the aims of the company's rehabilitation programme is to re-establish the faunal communities which existed prior to mining. In the summers of 1981, 1987 and 1993, company biologists conducted bird surveys as part of a case study to determine the extent of avifaunal recolonisation in representative mined areas. Analysis of monitoring data collected during the three surveys of the same areas showed considerable variation in the avifaunal communities of three rehabilitated sites. Numbers of bird species and bird diversity in a site seeded with dense understorey continued to increase, and by 1993 all avifaunal community parameters measured in this site were equal to or greater than those recorded in healthy unmined forest. Bird species numbers increased in a site given fresh topsoil but not seeded between 1981 and 1987; however, all parameters showed little further change by 1993. The oldest site, which was not seeded or given fresh topsoil, showed the greatest degree of change. In 1981, it supported only one bird species, but by 1993 all bird community parameters were similar to those recorded in the site which received fresh topsoil but no seed. Species composition of all rehabilitated sites' avifauna also changed. The similarity of bird community composition increased over time. By 1993, the healthy forest communities were more similar to those of some rehabilitated sites than to those of forest degraded by dieback disease. The study demonstrated that development of the vegetation community is a key factor controlling the composition of bird communities in rehabilitated mine sites. Recommendations are given to further promote avifaunal recolonisation following mining. (C) 2000 Elsevier Science B.V. All rights reserved.