"Use on a planet to designate it as a wildlife sanctuary, allowing you to place a variety of abducted creatures to live in safety."
The Wildlife Sanctuary allows you to place up to 30 species of creatures on a planet. However, you and other empires cannot colonize nor terraform a planet once it is designated as a sanctuary. Thus if you wish to have a full set of plants to easily grab for a full ecosystem transfer, terraform the planet fully before you place the Wildlife Sanctuary.
The Wildlife Sanctuary designation can be removed by destroying the building planted. Removing it will kill off all species except those that can fit in the current terrascore.
If you place the sanctuary down, you can see the actual nests of the animals.
Given the above restrictions, planets with no spice resources (which cannot be colonized by the player except by using a Monolith) are excellent choices for Wildlife Sanctuaries. The planet where the player finds the crashed UFO in his/her home system is one such world, as is the planet with the Grox-destroyed colony. If more are needed, a planet with a T-score of T1 and up and red spice will do fine
There is one glitch associated with the Wildlife Sanctuary. Rarely, one of the species on your wildlife sanctuary will evolve from the creature stage to the tribal stage. However, this is nothing serious and can even be fun to watch sometimes, although the tribe may wipe out some of the other species in your ecosystem. After that sometimes there is more then 30 species on that planet (the text will be like "31/30").
Tip: Unlike colonies, they are not marked on the star map when you zoom out, therefore it's very easy to forget where they are. It's best to put them in the same system as one of your colonies and in a star system near or next to one of your colonies' star system. Like in your galactic neighborhood for example.
You can think of the Wildlife Sanctuary as a sort of animal and plant storehouse. Since you can see the nests on the minimap and scrolling over a nest shows you what species it is, you know what is where when terraforming planets, plants are just found all over the place, making a T3 Sanctuary just as good as a T1.
This tool uses purchased ammunition.