Comparing the ecological and physiological traits of the critically endangered tree Melaleuca irbyana to the more commonly distributed Melaleuca bracteata
This project is generously funded by Logan City Council, which has also supplied a great deal of invaluable in-kind support.
Melaleuca irbyana (swamp tea-tree) is a small to medium tree, 8-12 m high, with papery bark and tiny leaves. Melaleuca irbyana communities are listed federally as critically endangered under the Environment Protection and Biodiversity Conservation Act 1999 and is protected under the Beaudesert Shire Planning scheme 2007 as an overlay in the Nature Conservation Overlay.
Remaining populations of Melaleuca irbyana’s co-occur with areas of South East Queensland that are experiencing the highest urban expansion rates and is therefore under threat from increased clearing and common effects of increasing urbanisation such as eutrophication. Recent mapping activities found only 998 hectares of Melaleuca irbyana forest in its original form, which is just 8.1% of its pre-European distribution. In Australia, there are approximately 250 species in the Melaleuca genera with some species being widely distributed and others having a very limited distribution. Not only is its habitat under threat, but Melaleuca irbyana is also a species with a limited original distribution; therefore, it may have a set of reproductive, water-use and nutrient-use traits that explains its limited distribution and if understood could aid its recovery.
The purpose of this study is to assist in more effective management of existing populations of Melaleuca irbyana and improve the efficacy for future Melaleuca irbyana revegetation projects. We will do this by measuring a number of key ecological and physiological traits of Melaleuca irbyana (adults and seedlings) and compare these characteristics to the more common Melaleuca bracteata that overlaps in its distribution with Melaleuca irbyana.
The characteristics measured will assist with both the more effective management of Melaleuca irbyana by allowing us to pinpoint the traits that are likely limiting survival and expansion of Melaleuca irbyana. We will quantify the following traits for both species: germination rates and cues, seedling growth and development, adult growth rates, seedling and adult water and nutrient-uptake.