Usually, desperate for food, the starving rabbits will ringbark trees and eat virtually every plant possible before they disappear. Thus, the topsoil becomes unstable and what doesn't blow away is washed out by the rains. This is what happens when there are few naturally adapted predators to hold rabbit populations in check during the boom periods. Despite the rabbit calicivirus not being native to Australia, its recent escape is one of the more dramatic bottleneck events in the history of rabbits in Australia. Faced with new threats though, the prolific breeding capacity of the rabbit quickly ensures that some have a genetic make-up capable of beating the new odds.
Weaker viruses are therefore much more likely to survive.
Removing rabbits effectively relies on using a number of methods at the same time and the removal of habitat is the best. For example, a property on which I often ferreted and shot rabbits back in the 1980s had a lot of rocky outcrops and blackberry bushes and therefore had a moderate to high rabbit population. The property was in a reasonably high rainfall area so it did not experience water stress. A new owner came and replaced the sheep with angora goats. Within a few months, all of the blackberry bushes disappeared and the brush around the burrows up in the rocky areas was soon cleared as well.