The lyrebird, Menura novaehollandiae, was introduced to Tasmania from Victoria in the 1930s and 1940s for conservation purposes, as it was perceived to be threatened with extinction. This species inhabits mixed forest and rainforest and obtains its prey, invertebrates, by scratching in the soil and litter layers. The lyrebird therefore poses a threat to invertebrates through predation and destruction of habitat. The species also poses a threat to vegetation, through disturbance of the soil, and removal of individual plants. The lyrebird’s range was estimated from available records.
Predictions were made regarding the species’ potential range, and the time period that it may take the lyrebird to reach this range. Records showed that lyrebirds occur in most of the mixed forest in central and southeast Tasmania. Potential habitat lies in the north-west, far south-west and north-east of the state, as well as Bruny Island and the Tasman Peninsula. Lyrebirds are unlikely to reach the latter three areas in the eastern part of Tasmania due to a lack of connectivity between areas of suitable habitat. Lyrebirds will probably reach the north-west and far south-west within the next decade.
The lyrebird’s impact on invertebrates was studied using an exclosure experiment. Areas protected from lyrebirds were compared to unprotected areas, which allowed the examination of changes in abundance of invertebrates. No difference was detected at the community level, but superfamily Staphylinoidea was significantly more abundant in areas protected from lyrebirds.
The use of this group as bioindicators is discussed. The lyrebird’s impact on Tasmanian vegetation was assessed by comparing sites where lyrebirds are present with similar sites that are free from lyrebirds. As expected, there was considerable variation between sites, in terms of abiotic characteristics and composition of tree species.
There was as much variation between the two site types as there was within them. Undergrowth vegetation varied significantly between lyrebird and non-lyrebird sites. Ground fern cover was greater, and saplings were significantly more numerous at non-lyrebird sites. Such changes in the structure and composition of Tasmanian mixed forest communities are pertinent to vegetation management and broader conservation issues.
