Erika Haggstrom very kindly send me an email with this link: http://news.yahoo.com/s/ap/20090113/ap_on_re_au_an/as_australia_rabbit_infestation
here you can read how it is very important to be aware of the connections that exist in our environment. Some times we think that "controlling" something will not have any negative effects and soon will find that there are negative consequences. The moral of the story is that we have to use caution when dealing with altering the environment.
Thanks so much Erika for this information!