Extinction Rate Statistics Attributed to Foxes and Cats...

Extinction Rate Statistics Attributed to Foxes and Cats One of The Dingo Debate’s strongest factual arguments was its analysis of extinction rates where there were and were not any dingoes. Johnson from James Cook University discovered that mammals and marsupials in areas with healthy dingo populations survived much longer than they did in environments that did not have dingoes. In fact, 90% of ground dwelling mammals had gone extinct in areas where dingos had been banished from. This local extinction rate was the direct result of foxes and feral cats. Johnson further states that “his interest in protective effect of dingoes began years ago”. Johnson Study Johnson’s interest in the protective effect of dingoes began when we was working on a northern New South Wales cattle farm that was owned by “very good naturalists”. He was conducting a study on wallabies in the area. To his surprise there were no foxes in the area. The property owners explained to Johnson how they didn’t bait dingoes because they understood the importance of apex predators in an environmental system and how vital they are to sustaining and maintaining the ecological balance. Johnson’s new perspective (from his disposition change on the dingoes) directed him to change his study on the cattle farm. His new study was to look at fox and cat population and how many threatened native animals were on the cattle stations. After weeks of meticulous research he did not discover any foxes or cats in the area. Positively he also found that the area was a haven for rat kangaroos, bettongs and threatend marsupials. Johnson further explained another eye opening situation that happened only a few weeks after he finished his study. A colleague of his was doing a study on the endangered rufous hare-wallaby in the Tanami Desert. While his colleague was studying the wallaby he observed that the dingo was occasionally eating them. He notified the local parks and wildlife services and it resulted in the poisoning of all the dingoes in the area. After the dingoes were poisoned from the site Johnson’s colleague stated, “Within two weeks, there were foxes on the site, and they killed off all the hare-wallabies. That species is now extinct on the mainland”. – Johnson’s Colleague (Levy, S. 2009) Key Observation of Mesopredator Release The upsetting outcome of the rufous hare-wallaby is a strong example of mesopredator release. Mesopredator release is when an apex predator (dingo) is removed from a system and the lesser predator(s) (cats/foxes) become unchecked and unchallenged. This is the syndrome of a worsened ecological balance due to the elimination of the top order predator that is replaced by the lesser predator. There have been several studies in North America with the same situation. All of the studies clearly show a negative impact on ecological balance. ~Gary Taylor Photography~