RE: Red foxes (Vulpes vulpes) were introduced to Australia for sport hunting in the 19th century, but ended up being responsible for the extinction of several native species, including the desert rat-kangaroo (Caloprymnus campestris)
That's a good question. I don't know the details, but I would assume that the conditions for the rabbits were very good, so they were able to spread a lot more quickly than the foxes. They also have a much shorter generation time, and can have an exponential growth because of how many offspring they can have. So I think they were simply a perfect fit for Australia, while the fox took a little longer to spread and grow in numbers.
The desert rat-kangaroo fed on plants and some insects, and you might be right. However, both these organisms probably have other factors that prevent them from becoming too abundant (I would assume water since they lived in desert regions). But yeah, it can have cascading effects on the food web for sure! Sadly I don't know much more about this specific case :(
But thanks for leaving a comment, @nathen007!
Its always the best writers that leave me thinking so much I end up with more questions than answers and then make me read further :-)
This was a great read, thanks for sharing, i'v always been interested in things of this nature. I think that if they were to introduce the rabbit it would cause a trophic cascade and potentially be detrimental to other species which rely of the same food sources as the rabbits.
You're welcome. I'm glad you liked it :)
The rabbits are already introduced to Australia; it happened about the same time as the fox.