Endangered Species

[Matternich]

Endangered species tiles (or areas of natural importance) should appear in the late industrial/early modern age, but not within city zones.
If these tiles are improved beyond a road the species have a increasing chance of extinction which makes citizens upset- "100% Stop destroying our wildlife."
Perhaps just have Ivory and Furs 'flip' into these tiles at some point.
These tiles could act as a non-tradable luxury resource.
Or alternatively provide a culture point each turn to the nearest city.
Or at least enable a small wonder- 'National Reserve Park', or city improvement- 'Zoo'- for content faces and culture points.
There could be similar endangered marine life squares with killer whale or dolphin which offshore platforms would destroy.

Speaking of the sea how about pearls/caviar/coral as luxury resource requiring harbour or colonizing vessel? Possibly even the 'oil' resoure at sea requiring- Offshore platform as well.

 

[Chukchi Husky]

You could use endangered species as a resource. If you use it (poachers), you would gain some gold per turn (it will eventually disappear) and you would take a serious reputation hit (this would only apply to later eras). If you 'preserve' an endangered species tile then your reputation would go up and you would gain a small steady income (from tourists and charities). The amount of gold from tourism would be less than from poachers.