Page 2113 - Week 07 - Tuesday, 2 August 2022
Next page . . . . Previous page . . . . Speeches . . . . Contents . . . . Debates(HTML) . . . . PDF . . . . Video
The sustainable kangaroo populations on conservation land is calculated in accordance with the Nature Conservation (Eastern Grey Kangaroo) Conservation Culling Calculator Determination 2018. The ‘one per hectare rule’ is the basis for this calculation and is set as the desired sustainable kangaroo density in grasslands under average climatic conditions. The sustainable number is scaled down with increasing tree canopy cover. This base density is then adjusted up or down based on current vegetation and climatic conditions. Annual site specific population estimates are used to calculate how many, if any, kangaroos need to be culled to achieve the desired density. Minimum population densities are retained to ensure no risk of extinction from culling activities.
The Petition questions the accuracy of the ACT Kangaroo Population surveys.
The ACT Government relies on the best practice scientific methodologies for undertaking kangaroo surveys and population estimates.
The ACT Government is aware of a recent report “Eastern Grey Kangaroos in Canberra Nature Park. Population estimates and culling history 2009-2021. A citizen science project April 2022”. The report details surveys for kangaroos undertaken in 37 Canberra Nature Park reserves with a total of 4,074 kangaroos reported. The counts for individual reserves have been redacted from the report. The ACT Government is a supporter of citizen science and commends the authors for the report.
However, the ACT Government is confident in its kangaroo population estimates that use robust counting methods suited to the individual sites. The citizen science report uses a single method known as “Direct counts” which is a valid method in some circumstances. Direct counts require observers searching the entire site and counting all individual kangaroos without missing any or counting any more than once. Repeat counts should be undertaken to validate results. This method of counting is only suitable for small sites with open vegetation and requires a high amount of knowledge about the site and the behaviour of the animals.
The direct count method is not suitable for many ACT nature reserve sites because of their size, vegetation and terrain. Attempting direct counts at these sites is likely to result in an underestimate of the true population size.
At these sites, ACT Government uses two other count methods – sweep counts and walked line transect counts.
• Sweep counts involve a coordinated line of people walking across a site and counting the kangaroos that move through the line. This type of count requires careful coordination of the counters, aided by the use of 2-way radios and maps. This type of count is suitable for sites larger than those that can be counted directly, and where the vegetation and terrain allow for good visibility from one counter to the next.
• The ACT Government now relies largely on walked line transect surveys which is suited to larger more heavily vegetated sites where kangaroos cannot be reliably counted by a direct or sweep count. Surveys utilising the walked line transect method adopt linear transects which, importantly, are unbiased with regard to landscape features such as roads or waterbodies, that are known to influence the distribution of kangaroos across the landscape and hence risk a bias in abundance estimates.
Next page . . . . Previous page . . . . Speeches . . . . Contents . . . . Debates(HTML) . . . . PDF . . . . Video