|
Feral animal pests
 The term ‘feral animals’ is generally used to describe exotic animals which have established themselves in the wild. Exotic animals are those introduced to Australia from overseas and may also include Australian wildlife which has been moved outside of its natural range. Most feral animals are either exotic, domestic animals that have gone wild or exotic animals that were introduced into the wild for pest control or for recreational use. Most invertebrate feral animals were introduced as stowaways in transport containers or in imported crops and produce.
The impacts of feral animals on the values of the Wet Tropics may include predation on native species, competition for food and habitat, degradation of habitat, soil erosion, disease and weed transmission, and changes in fire regimes. Feral animals such as pigs and dogs can also be pests for primary producers and WHA neighbours. A cooperative and committed approach to management between protected area managers, local government and private landholders is required for any controls to be effective. The Wet Tropics Conservation Strategy provided a list of some feral animals currently threatening WH values, or with potential for damaging impacts. This list was based largely on feral animal research done by Deborah Harrison and Brad Congdon - Wet Tropics Vertebrate Pest Risk Assessment Scheme (2002).
Many feral animals such as pigs and cane toads are widespread and have already established high population numbers within and around the WHA. Complete eradication of such established feral animals is impractical as current technology and resources are inadequate. Biological control options are being pursued for the cost effective eradication or control of established feral animals such as pigs and cane toads. Until such controls are developed, management is focused on reducing localised populations in areas where feral animals have a significant impact on biodiversity or farm productivity. For example, feral pigs can cause extensive damage to native vegetation and crops (see the case study on pigs below) and feral dogs can kill farm animals. There are a number of feral animals in the WHA which are not currently a major problem but have the potential to spread throughout the Wet Tropics. Rabbits, foxes, goats and deer threaten open forest systems especially. Fish species, such as the tilapia, guppy and gambusia have huge potential to dominate aquatic systems. Invertebrate species such as the crazy ant, fire ant, European bee, fruit fly, palm leaf beetle and spiralling white fly have also been recognised as a potential threat to WH values. For instance, crazy ants have already devastated rainforests on Christmas Island and two outbreaks have occurred around Cairns in recent years.
 Preventing the establishment of these new feral animal species around the World Heritage Area is highly important for conservation management as well as for quarantine, economic and trade reasons. Feral pigs, cats, foxes and rabbits have been listed as key threatening process under the EPBC Act. A National Threat Abatement Plan has been released recently for pigs. The Land Protection (Pests and Stock Route Management) Act 2002 has now declared three classes of pest animals which may have adverse economic, social and environmental impacts in Queensland. Class 1 animals are subject to eradication from the state, but include none of the major Wet Tropics feral animals. Landowners, including State agencies and local government, must take reasonable steps to keep land clear of Class 2 animals. This applies to feral pigs, dogs, cats, foxes, rabbits and goats in the Wet Tropics. No animals are currently listed in Class 3 as having primarily environmental impacts. Fish are regulated under the Fisheries Act 1994 and tilapia and mosquito fish are both declared noxious.
A number of methods and techniques are currently available for the control of feral animals, including fencing, trapping, shooting and poisoning. The type of control method chosen depends on the target species and the environmental surrounds. The effect of control techniques on non-target native species is an important consideration.
Fish stocking
The stocking and translocation of large predatory native fish such as barramundi and sooty grunter has been undertaken throughout the Wet Tropics, often in upstream areas which have naturally remained free of such predators. This can significantly alter faunal communities and ecosystems in streams, and cause localised extinctions or declines in local fish populations (Burrows 2004). For example, the introduction of several native fish species including mouth almighty and sooty grunter to Lake Eacham resulted in the local extinction of the endangered Lake Eacham rainbow fish, although small populations have now been found in neighbouring streams. Redclaw crayfish have also been extensively stocked and translocated in the Wet Tropics (outside of their natural range of the Gulf of Carpentaria and north eastern Cape York) with likely adverse consequences for native crustacean species and aquatic plants. Fish stocking in National Parks is prohibited by section 86 of the Nature Conservation (Wildlife) Regulation 1994 which prevents a person taking a live animal into a protected area.
Declared animals of Queensland
 There are three classes of declared animals (two of which are currently used) under the Land Protection (Pest and Stock Route Management) Act 2002. These animals are targeted for control as they represent a threat to primary industries, natural resources and the environment. Declaration imposes a legal responsibility for control by all landowners on land under their management, including all landowning state agencies. Unless you have a permit, it is an offence under the Act to:
- introduce a pest animal to the state
- feed a declared pest animal
- keep a declared pest animal
- release a declared pest animal.
More information
|
