Integrated rabbit control

Prolific reproductive potential has helped the European rabbit become a very successful invasive species. Originally from North Africa, the European rabbit spread north through Italy to the British Isles and then around the world, causing ecological havoc in some countries. On the Hawaiian island of Laysan, the rabbit is credited with wiping out 22 of 26 native plant species at the beginning of the twentieth century.

Since its mid-nineteenth century introduction into Australia, the European rabbit has been a major plague. Vegetation is grazed from vast stretches of land that become more desert-like and less suitable for livestock grazing despite the killing of millions of rabbits every year. Over a century after starting rabbit mitigation programs, Australia still spends an estimated $373 million per year on rabbit control.

Eradication is deemed feasible only on small islands or in small localized areas where rabbit populations are newly established. The few small islands off the coast of Western Australia where rabbits have been eradicated are the exception, not the rule. More typical is 46 mi2 (120 km2) Macquarie Island and the main Australian continent, where rabbits are so well-established that eradication has been replaced with the more realistic goal of population suppression.

Population suppression is accomplished using a suite of varied biological, mechanical, and chemical control techniques. This integrated pest management approach includes predators, microbial control agents, warren ripping, and electrified and wire-net fences. Wild rabbits are also hunted and

"harvested" as a commercial product. Barrel or soft catch traps are still used against small isolated rabbit populations. (Humane considerations have largely precluded continued use of the traditional steel-jawed leg-hold trap.) But rabbit populations are so high and the species is so prolific that shooting and trapping have no significant impact on populations.

A variety of poisons and fumigants are still used against feral rabbits, though safety, environmental, and humane concerns have been raised. The most widely used vertebrate control pesticide is 1080 (sodium monofluoroacetate), which is formulated into paste, pellet, food cube, grain, and carcass baits to poison animals such as rabbits, feral pigs, wallabies, wombats, dingos (wild dogs), possums, rats, mice, and foxes. Food chain risks are inherent in poison baiting, particularly when individuals lack baiting expertise. Another drawback is that sheep, cattle, horses, goats, cats, dogs, some native wildlife, and humans are also very susceptible to 1080, and there is no known antidote to the poison.

Destroying warrens by ripping or plowing is a less controversial alternative to poisons, though the two techniques are sometimes combined. Sometimes rabbit kill is maximized by using dogs to drive rabbits into their warrens before burrow destruction commences. But rocky areas, riversides, and steep sandbanks with rabbit warrens are impossible to rip up and destroy, short of explosives.

In some locales rabbits prefer surface refugia rather than warrens. This means habitat management may be needed. However, the same shrub, blackberry, and log debris habitats favored by rabbits are also home to desirable species of birds, reptiles, amphibians, and other small mammals. So, it is not always desirable to modify the habitat to fight rabbits.

Common house rats (Rattus rattus) drinking milk in a temple in India. Though often considered pests, some religions consider rats to be holy. (Photo by M. Ranjit/Photo Researchers, Inc. Reproduced by permission.)
The eastern mole (Scalopus aquaticus) eats helpful invertebrates such as earthworms, which turn and aerate the soil. (Photo by L. L. Rue, III. Bruce Coleman Inc. Reproduced by permission.)

Biological control using predators, parasites, or microbes can be part of integrated rabbit control programs and help overcome the limitations of poisoning and habitat modification. One of the more famous instances of biological control was the introduction of the myxoma virus to fight rabbits.

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