I found this planning document available online relating to the African Savannah and Congo Forest precincts at Taronga: https://majorprojects.planningportal.nsw.gov.au/prweb/PRRestService/mp/01/getContent?AttachRef=SSD-8008!20190228T003458.929 GMT
It's from 2017, so I believe that there have been some changes of plans since then; however, what is does show is how the zoo is seeking to (or has sought to) use the existing plant life and the sloping site in order to construct new exhibits. While these plans aren't gospel (for instance, as far as I can see there isn't an exhibit for pygmy hippo, and what's marked as a lemur exhibit now holds capybara), I do note that the existing gorilla exhibit isn't included within the area to be redeveloped.
My view would be this is a matter of practicality (as in, the new gorilla exhibit needs to be separate from the old one unless there's somewhere else for Taronga to house the gorilla troop in the meantime), although it does provide the opportunity for that space to be redeveloped to house bongo and pygmy hippo once the gorillas have moved into their new exhibit.
Thanks for attaching that. It aligns with the comments in the email I received from Taronga Zoo late last year that while Okapi hasn’t been ruled out, the central focus of the new precinct will be the gorillas.
My interpretation, supported by these plans, is that the priority is to construct gorilla exhibits to house a breeding troop and bachelor troop; followed by building an exhibit alongside for Okapi (the goal) or Eastern bongo (the back up). From here they can explore options of redeveloping the site of the exisiting gorilla exhibit to house Pygmy hippopotamus or an alternative species they decide on the interim.
I do believe Pygmy hippopotamus will have a future at Taronga. They had a long standing association with them and they’re popular with visitors. With rhinos and Common hippopotamus long phased out and elephants set to follow, they’d be wise to retain this (albeit significantly smaller) ungulate imo.