Australian National University, Canberra. Completed.

Seasonal habitat use, food resources and Aboriginal perceptions of the feral pig ( Sus scrofa ) in the Arafura wetlands, Northern Territory

Summary | Aims | Research Methods | Aboriginal input | Progress |

Feral pig damage along drainage lines in sedgeland. Photo: Anthea Dee

Summary

Feral pigs ( Sus scrofa ) are widespread throughout most of Australia, including the Top End of the Northern Territory where they are found in a variety of habitats. Their behavior is perceived to threaten natural ecosystems most notably by their diggings, which cause disturbance to soil and natural vegetation. They prefer thick cover and need almost constant access to water especially in high temperatures. This excludes them from the arid centre of Australia and usually limits them to coastal areas or edges of rivers and swamps.

Pigs are true omnivores. Their diet is varied but relies heavily on plant material including grasses, leaves, fruits, nuts and berries. They also prey on a range of insects, frogs, reptiles and small mammals. Feral pigs are a threat to the environment through their feeding, by their destruction of habitat and competition for food, water and shelter. Their digging causes erosion, damages the roots of native plants and disturbs soil, which can assist in the introduction and spread of weeds.

Feral pigs shot by two members of the Wanga Djakamirr rangers near Gatji outstation Photo: Anthea Dee

Aims

Broadly, this project aims to take a holistic approach to the development of a feral pig management plan for the Arafura Swamp, in north central Arnhem Land, by integrating scientific research with contemporary Aboriginal knowledge and aspirations. As well as engaging the major conservation issue of management of feral animals on Aboriginal lands, the project considers the disparate values of feral pigs to various stakeholders.

Complete eradication of feral pigs is recognised as a virtually impossible and uneconomical task. Controlling pig numbers is more practical although this can still be very expensive and in many cases is largely ineffective. More effective and efficient control might be achieved if adequate information was available on feral pigs' seasonal use of different vegetation communities and food resources.

Research methods

Hence, spatial and temporal patterns of habitat use by feral pigs are considered in this region. Quantitative signs of pig damage as well as simple presence/absence data have been collected from a series of sites located in different vegetation types along the western side of the Arafura swamp. A range of basic ecological data has also been collected to try to determine whether specific factors influence where pigs go to at different times of year. Resulting data will be applied to the development of a predictive model of seasonal feral pig habitat use and will be used to devise more efficient control methods.

Anthea and Norman marking a survey site at NangalalaI

Aboriginal input

In addition, the project aims to develop an understanding of how local Aboriginal people feel about feral pigs and their affect on bush foods and on country in general. This ethnographic perspective is essential to understand when developing management plans on Aboriginal land. Feral animals and weeds are relatively new to this part of the top end, an area with a history of uninterrupted traditional Aboriginal land management. Many of the problems associated with these new weeds and animals are unfamiliar to Aboriginal people and it has become important that land management now be looked at and executed using both indigenous and western scientific knowledge. Aboriginal people can contribute much to the battle against invaders through their acute familiarity and understanding of the natural landscape in which they live. They are the best source of knowledge about changes in the landscape on both a broad and micro level.

The local Yolngu people have had a great deal of involvement in the project at various levels from site location suggestions and identification of animal signs to long discussions about damage caused by feral pigs and concerns for the health of people and country. Their participation in surveys has allowed a two-way transfer of knowledge and skills between researcher and Aboriginal collaborators which is an invaluable process.

Research progress

Work over 2000-1 focused on completion of field surveys (July and September 2000) and then data analysis and writing. Data analysis to date has involved seasonal based general linear regression analyses and general linear mixed modeling with the aim of determining which ecological variables measured are best at explaining feral pig presence.

The Wanga Djakamirr ranger unit along with the Caring for Country Unit (NLC) has greatly assisted with the field program and has provided access to essential facilities in the field. Many of our research activities have been coordinated throughout the year to facilitate knowledge exchange and learning.