Melanie, I think bottlebrushes or paperbarks, Melaleuca spp., have got into the everglades. Awful. Managing them can be hard. In our heaths, here, they just take over if burning is kept out. Bye bye heaths.
That's the Cane Toad, Bufo marinus, introduced from Hawaii where introduced from South America. They lay 30k eggs at a pop = 30k toxic toadpoles. What was that? That was your fauna dying.