Melaleuca irbyana: Community ecology and seedling establishment of a critically endangered species
Melaleuca irbyana is an Australian tree which is federally listed as critically endangered under the Environment Protection and Biodiversity Conservation Act 1999. This species of swamp tea tree or paperbark occurs in small remnant reserves within South-east Queensland and North-eastern New South Wales. Recent surveys indicate that only 998 hectares of this species remains intact, being just 8.1% of its former range.
Increasingly, the areas in which Melaleuca irbyana survives in South-east Queensland are under threat from rapid urban expansion and associated clearing. Despite the critically endangered status of Melaleuca irbyana, relatively little is known about the natural seedling establishment of this species nor biodiversity associated with its remnant habitats. In addition, observations and advice from Ipswich Local Council Officers indicate that they believe recruitment of new seedlings in some of the remnant reserves, for example Purga nature reserve, has slowed or may have stopped all together.
This study tested the theory of island biogeography using the size, age, isolation and shape of remnant forests of Melaleuca irbyana as predictors for the “health” of the reserves. A healthy reserve would be one that is regenerating naturally (i.e. seedling establishment is taking place) taking into account the known life-cycle of this species and associated biodiversity. The tests will look for relationship between associated biodiversity (species richness) of other plants and possibly birds and mammals within the reserves and also seedling establishment of Melaleuca irbyana (i.e. natural regeneration). In addition, soil characteristics within the reserves will also be surveyed and used as a potential predictor of reserve health and preferred soil composition for this species.
The aim of this study is to assist local government in the effective management of this species. And will potentially aid managers to determine where new plantings of Melaleuca irbyana would be most successful and if active restoration of some remnants is necessary.