This dataset contains the estimated distribution and abundance of cassowaries across the Wet Tropics Region and the sub-regions used in these estimates. The key areas for cassowary conservation are those with the highest densities and abundance.
This data is based on field surveys and data on cassowary density derived from faecal-DNA analysis of dung samples collected during those surveys.
Methods:
Surveys were conducted along 157 transects distributed across the Wet Tropics Region during 2012 - 2014. During these surveys all forms of cassowary sign were recorded and in the case of dung the dung was also collected. Cassowary DNA was extracted from the dung samples and DNA fingerprinting analysis was used to identify individuals. Based on the relationship between dung encounter rates and density of cassowaries at 8 focal sites, the density of cassowaries and their abundance on transects in each of 23 sub - regions was estimated.
The sub - regions were based on the estimated cassowary essential habitat. Essential habitat is based on verified sightings of the Southern Cassowary since 1980 and includes vegetation considered to be important for the species in terms of foraging, breeding or other parts of the species' life cycle. This habitat is considered to be necessary for the long-term survival of the cassowary. The important vegetation types associated with essential habitat (91 Regional Ecosystems) are listed within Kutt and colleagues (2004).
Further details of the methods are provided in the technical report for this work, Westcott (2014).
Limitations:
eAtlas Note: The original shapefile provided by the researchers has very fine boundary mapping from the cassowary essential habitat mapping. This is then broken down into 23 regions. The scale of these two datasets is vastly different and needs to be considered when using or interpreting this data.
A slightly lower resolution version of this data was prepared for download from the eAtlas. This reduces the fine scale habitat mapping slightly, whilst retaining the cassowary regional information. The mapping layer associated with this record corresponds to the original high resolution version.
Format:
Original Shapefile (452 polygons, 25 MB) of the 23 subregions of the Wet Tropics with estimated density and animal numbers. The detail of the region boundaries are based on very detailed estimated essential cassowary habitat mapping Kutt (2004).
Simplified Shapefile (23 polygons, 2.6 MB). This contains the same cassowary estimated density and animal numbers across the Wet Tropics except with simplified habitat mapping. This was derived from the original by dissolving polygons with the same data, then smoothing the polygon using a 150m filter, then simplifying the polygon with an allowable tolerance of 15 m and removing features smaller than 2 hectares. This shapefile was prepared by the eAtlas team. This simplified version is more suitable for large scale maps.
Data Dictionary:
- CassBound: Name of the cassowary mapping region
- CassDens: Estimated density of cassowary in animals per square km.
- Cass_num: Estimated number of cassowaries in region.
- Hectare: Area of the mapping region in Hectares.
References:
Kutt A. S, King S., Garnett S. T. & Latch P. (2004) Distribution of cassowary habitat in the wet tropics bioregion, Queensland. Technical Report to the Queensland Environmental Protection Agency. Environment Protection Agency, Brisbane, Queensland.
Westcott, D.A., Metcalfe, S., Jones, D., Bradford, M., McKeown, A., Ford, A. (2014) Estimation of the population size and distribution of the southern cassowary, Casuarius casuarius, in the Wet Tropics Region of Australia. Report to the National Environmental Research Program. Reef and Rainforest Research Centre Limited, Cairns (21pp.).
