As I found out, the only way to exterminate such species is to let enemy take the planet and then bomb it, and then (re-)colonize.
This is irritating. Because there is not always any enemy around, and also a colony ship is wasted for that.
We need some 'exterminate' button (possibly with diplomatic consequences), similar to 'forced labor' for enslaved population.

Forgot to mention, there is a way for Tinkers, to just not build farms, so they die of starvation.
And yet the 'exterminate' button would be more flexible.

We specifically do not have such a feature because we do not want you to be able to exterminate undesired native races. That's part of the reason why they can't be enslaved.

The native race is part of the advantage or disadvantage of that particular planet. I don't think it's that easy to annihilate a native species (short of destroying the entire ecosystem of the planet).

If I come across an enemy planet that has an undesired species (especially the yellow blobs) I often bomb the planet back to stoneage, then colonize it with my own colony ship. I do agree with Arioch that it should be hard to exterminate a native species, but at least cull the species (especially for an "evil" dispostion) so that the species after a while is not the dominant species of the planet. Also would be fun to allow the bombing solution to be hampered with environmental detriment (just think about it, several hundreds nuclear devices on the planet and the new colonists just walk in like nothing ever happened).

I suggest the following solution:
1. Allow culling, either by not giving them food or by some other way (no need to be specified in game). Of course this will make them unhappy but will keep their growth rate below the main race.

2. Allow bombing the planet to 50% the growth rate of the population (for eradicating) or 75% (for just bombing) for maybe something like 10 turns. This also have the upside to make bombing a less viable option since growth rate of the population is an important factor.

Arioch wrote:We specifically do not have such a feature because we do not want you to be able to exterminate undesired native races. That's part of the reason why they can't be enslaved.

The native race is part of the advantage or disadvantage of that particular planet. I don't think it's that easy to annihilate a native species (short of destroying the entire ecosystem of the planet).

But there is a contradiction - I can just bomb them without any consequences for planet.

I think there should be a technology to enslave native races. And maybe the technology should be bought for metal from Arda Seed, when you have enough reputation. This would be a good reason for cooperation with Arda Seed. Because currently there is no useful technology that can be bought from them.

However, 'consequence free bombing' probably won't be a feature forever; I believe the intent is once a better Terraforming model gets implemented that too much bombing can lead to environmental degradation.

-Will