Feral buffalo (Bubalus bubalis): distribution and abundance in Arnhem Land, Northern Territory.
21 Seiten, NT Govt.
Populations of feral buffalo Bubulas bubalis in Arnhem Land provide both an economic opportunity and a source of significant environmental damage. There has been no consistent management of feral buffalo in the Northern Territory since the Brucellosis and Tuberculosis Eradication Campaign (BTEC) of the late 1980s and early 1990s. Local control programs have been undertaken in response to concern about buffalo impacts, but these programs have not been coordinated or integrated at the regional level. The development of a strategic management program for feral buffalo in Arnhem Land requires adequate baseline data on the distribution and abundance of buffalo across the region.
From 9 June to 23 June 2014, an aerial survey was conducted to determine the distribution and abundance of feral buffalo (and other large feral vertebrates) in Arnhem Land, Northern Territory. The total survey area of 91,658 km2 was surveyed at a sampling intensity of 3.6%. Species counted were buffalo, cattle, donkey, horse and pig. Buffalo counts were corrected for perception (observer) bias, but uncorrected for availability (habitat) bias.
The corrected population estimate for feral buffalo in Arnhem Land was 97,923 ± 9,327, a density of 1.07 ± 0.10 buffalo per km2. This estimate has a precision of 9%, which is considered good for such broad-scale aerial survey. Population estimates for other feral species were not calculated as sightings were too few for estimation with an acceptable level of precision.
The 2014 survey recorded relatively high buffalo densities in a number of areas:
- a large area to the north-west of Bulman and south-east of the Arnhem Land Plateau;
- the floodplains of the Blyth and Cadell Rivers;
- the coastal floodplains between the Blyth and Glyde River mouths;
- the floodplains and wetlands to the south-west of Buckingham Bay;
- the floodplains and wetlands north of the Roper River, downstream from Ngukurr;
- the south-west corner of the survey area.
Previous (1985 and 1998) surveys also recorded high buffalo densities in the Bulman area, but these surveys showed moderate to low buffalo density throughout the rest of Arnhem