From the 2005 Carnivore TAG Action Plan:
"One of the aims of animal collection planning is to build larger, more robust populations. As a rough guide, for many of the carnivores held in Australasian zoos, populations of less than 20 (adult) animals are a short-term prospect only, relying on regular replenishment from stocks outside Australasia. Populations of 20-50 may be expected to persist over the short-medium term (> 20 years) though for longer term persistence they too would rely on being closely linked to overseas programs."
The region currently holds or plans to hold the following large cat species: lion, cheetah, puma, jaguar, Sumatran tiger, hybrid tiger, white tigers (show animals), African leopard, Persian leopard, snow leopard and clouded leopard. Excluding the hybrid tigers, and the white tigers, that would still mean that the region needs to have a minimum of 180 large felid spaces in order to manage this number of species for just the short-medium term, and our zoos have indicated that they do not wish to provide this amount of space to large cats.
Although discussions are ongoing, the current recommendation from the zoos themselves, is to concentrate therefore on lion, cheetah, Sumatran tiger and snow leopard and manage these effectively, with sustainable population sizes, and eventually phase out the other species (and not acquire additional large felid species). Collection plans are always changing, and are never finalised, and as such are reviewed by the zoos, on a yearly basis.
I'll try to find some more current plans for large cats in the next few days, if they exist.