Abstract
This study aimed to assess the habitat requirements and status of the endangered carpentarian grasswren (Amytornis dorotheae) in the (Gulf of Carpentaria (Northern Territory), including an assessment of potential threatening processes. The carpentarian grasswren is known only from the western (Gulf of Carpentaria, between Mt Isa in Queensland and the Limmen Bight River in the Northern Territory. Very little is known about the ecology of the species and its contemporary distribution and abundance are uncertain, particularly in the Northern Territory.The status of carpentarian grasswren in the Northern Territory was evaluated by surveying eight sites, selected for san1pling based on previous observations of carpentarian grasswren in the southern gulf region. Habitat characteristics were recorded at the study sites and were divided into three subsets of data including invariant data, variable data and floristic data. These data were than analysed at a quadrat scale, site scale and landscape scale.
The results suggested that a relatively large search effort (3.6hrs) is required to have a reasonable chance of observing carpentarian grasswren. Additionally, the mean success rate for successful searches was 67o/o highlighting the cryptic nature of this species.
Quadrats surveyed during this study were on average dominated by large rocks and outcrop, had a low canopy cover and low vegetation structure. Sites were generally dissimilar to each other for the three sub-sets of data but were significantly different to 20 randon1Iy selected sites in the Gulf of Carpentaria when combined and compared at the landscape scale.
Non detection of carpentarian grasswren at seven out of the eight sites suggests that this species has undergone an extensive range retraction since they were last surveyed by Martin and MacKean (1986). It is thought that the greatest threat to carpentarian grasswren is inappropriate fire regin1es altering the structure of the variable characteristics.
| Date of Award | Dec 2005 |
|---|---|
| Original language | English |
| Supervisor | Alaric Fisher (Supervisor), Penny Wurm (Supervisor) & Carol Palmer (Supervisor) |