I would stick with plants. In fact I would not even put an aquatic portion in place unless you are planning to have a very heavy duty filter system as well. Your skink will be very happy with the extra humidity produced by a little pond and will probably enjoy soaking in it if it is shallow as well as use it as a toilet area, but bear in mind that a healthy eating PTS will produce large soft and smelly poop that will rapidly foul the water and filter of a little aquatic area- much easier to have removable soaking bowls- which wouldn't work if you want to have plants in the water or even fish.
Soapbox: (I appologize if this sounds harsh) If you choose to adopt or purchase any animal- you are it's caretaker. Do your best to create an enclosure that will be healthy and enjoyable for IT. If it has visual interest for you, bonus for you, but don't jepordize your PTS just to make a more attractive enclosure for you. I would definitely not mix in any other species in the enclosure, unless you have a room sized enclosure and can find something from the Solomon Islands that normally co-exists in the PTS microhabitat. Setting up multispecies environment is a job for a Zoo, not the average herp fan. Where, may I ask did you see an enclosure with PTS and turtles? Generally speaking, mixing any lizard with any turtle is a big NO NO- for the reasons Zeteki states.
Good luck with your PTS, Jess B
for an aquatic area.
I'm wondering what other creatures would be safe habitating in the same vivarium as my skink. I've seen an enclosure with
PTS and aquatic turtles, but I'm not making a real large water area in the tank, just a smaller area about 5 gallons or so. I just
wanted to add a little more interest to the water feature by putting something alive in it, other than plants.