kakadu

kakadu national park and the environment

kakadu national park

Kakadu National Park is the second largest national park in the world. Situated in the Northern Territory, it covers an area of approximately 20 000 square kilometres. The major landforms and habitats in the park include an entire tropical river and its catchment (South Alligator), a sandstone plateau and escarpment, savannah woodlands, open forests, rivers and creeks, floodplains, mangroves and mudflats.

The beauty of Kakadu's scenery, its wildlife diversity, and the continuous occupation by Aboriginal people for 60 000 years have been recognised by the World Heritage Committee. The Park is one of only 17 (1998) places that has been given a World Heritage listing for both natural and cultural aspects. Kakadu National Park is jointly managed by Parks Australia and the traditional owners of the land. It has become a popular tourist destination, and with over 212 000 (1998) visitors a year, Kakadu National Park faces some difficult environmental management issues for the future. Some of these threats include:

Mimosa pigra (mimosa) is a native plant of Central America. This prickly shrub takes over floodplains, completely excluding native plants. At the moment, Mimosa covers an estimated 80 000 ha of the Top End. In Kakadu, an aggressive campaign of spraying, burning and removal is being undertaken by Parks Australia.

Brachiaria mutica (paragrass) was introduced to improve pasture for cattle. This grass is highly invasive and takes over floodplains, forming a monoculture and displacing native food sources for the millions of geese and other birds that come to Kakadu each year.

Salvinia molesta pictured above, is a free-floating aquatic fern, originally from South America. It has infested several creeks on the Magela floodplain in Kakadu and has covered several billabongs. This weed effectively chokes water bodies by reducing oxygen, raising hydrogen sulphide concentrations, lowering pH levels, raising water temperature and reducing the nutrient status of billabongs. A combination of chemical and biological controls are in place to try and prevent the weed from spreading.

Vehicles crossing creeks make the water muddy, affecting fish and other animals. Erosion controls have been put in place at vulnerable creek crossings.

Feral animals such as Sus scrofa (pig) and Bubalus bubalis (Asian water buffalo) are widespread in the Top End of the Northern Territory. These pests do a lot of damage to the wetlands, making the area much more susceptible to weeds and upsetting the natural balance of the area. For example, water buffalo create swim channels and break up floating grass mats, which usually act as barriers for fresh water. When these natural barriers are broken, the fresh water escapes prematurely, and salt water intrusions increase.

These are some of the environmental management issues that have to be dealt with on a day to day basis in Kakadu. With heightened community awareness and more scientific research , the answers to these and other environmental problems may be found.