Feral Animals of the Northern Territory
Feral Buffalo - Bubalis bubalis
Impacts
Feral buffaloes are a large herbivore weighing between 450 to 1200 kg and can cause extensive environmental damage, related primarily to their movements and feeding.
The most obvious signs of buffalo damage are disturbance of soils and vegetation owing to overgrazing and wallowing in mud. Buffaloes have also been implicated in the spread of weeds, particularly Mimosa pigra on floodplain habitats.
On inundated floodplain habitats, buffaloes undertake regular movements along pathways called “swim channels”. The movement of buffaloes along these channels destroys vegetation and erodes the soil creating new drainage channels. The alteration of floodplain hydrology by swim channels has been implicated in the landward expansion of sea water, termed saltwater intrusion, on the floodplains of the Mary River. Saltwater intrusion has been implicated in the loss of extensive areas of paperbark forest on the Mary River floodplains.
Habitat modification by feral buffaloes has been observed to reduce the nesting activity of magpie geese. This reduction in nesting activity has major management implications as magpie geese are an important resource for subsistence and recreational hunters. There is anecdotal evidence that grazing by buffalo may also reduce nesting activity in crocodiles, which has impacts on wild crocodile populations, as well as commercial crocodile enterprises. It is likely that buffalo may have major impacts on other flora and fauna but these impacts have not been documented.
Feral buffalo are of concern to agricultural and defence interests owing to their potential as reservoirs and vectors for disease. In particular, there is concern that buffalo have the potential to carry and spread foot and mouth disease, brucellosis and tuberculosis.
Background
Water buffalo were imported into the Northern Territory in the 19th century to provide working animals and meat for the remote northern settlements. When the early settlements were abandoned, the buffaloes were released, where they became feral populations. The buffaloes subsequently multiplied and colonised the Top End landscape, particularly the northern floodplains.
Distribution and Habitat
Buffalo occur in floodplain, woodland and sandstone escarpment habitats in areas where surface water is available. The range of buffaloes in the Northern Territory is restricted mainly to areas that receive greater than 1000 mm of rainfall annually.
The range occupied by feral buffaloes in the Top End of the Northern Territory appears to be increasing with the majority of the Territory herd in Arnhem Land.
Management
Aerial shooting is the best method for managing buffalo. However, there is some success associated with ground shooting. The Northern Territory Government is currently working with Indigenous communities in the north to assist in the development of management programs and monitoring procedures for buffalo.
Feral buffalo populations were not managed in the Northern Territory until 1939, after which time buffalo shooters were required to possess a license. In 1978, buffalo control began in earnest with an eradication campaign initiated in Kakadu National Park. Between 1985 and1995 the BTEC eradication program killed thousands of buffalo, mainly in the Adelaide / Mary river floodplains and western Arnhem Land.
At present, some herds of buffalo are domesticated and there is pet meat shooting and live export of buffalo from some areas. In general, the buffalo herds on pastoral lands receive some management.