What's the next Planet Zoo DLC after the Wetlands Pack?

Answer: Island Pack
The Island Pack is the tenth pack after the Wetlands Animal Pack.

Does the Island Pack have scenery?
The pack features island scenery pieces.

What are the animals confirmed for the next DLC being the Island Pack?
The animals confirmed for the Island Pack are the Walrus, Atlantic puffin, Great blue heron, Green sea turtle and Lord Howe Island stick insect.

What will the Island Pack come out?
The Planet Zoo: Island Pack will be available on Steam from June 28.