Population policies can now be set at an Empire-wide level, and also set for each colony. Population policies allow you to control which alien races are at your colonies, and what to
do with them.
There are two settings per colony: a setting that applies to all other races (except your own),and another setting that applies to races of the same family as your own. This allows you to have harsh settings for races not in your race family, but kinder policies for races of your race family.
Accept these races into your empire (this is how original Distant Worlds and Return of the
DO NOT ACCEPT
Do not allow migration of these races to the colony. This will prevent passenger ships from dropping off migrants from these races at the colony.
Actively migrate these races away from the colony to other colonies that will accept them. If you have enabled the empire policy setting “Use Penal colonies to implement Enslavement” then these unwanted races will be migrated to Penal colonies for enslavement there.
Enslaves these races, forcing them into hard labor.
For each race that you enslave, the corresponding empires of those races will take offense at your actions. The amount of offense is directly related to the population amount that you enslave. Enslavement also provides a bonus to the colony’s economy. The amount of the bonus depends on the proportion of the total population that is enslaved, up to a maximum of 50% if all of the population is enslaved. If you have enabled the empire policy setting “Use Penal colonies to implement Enslavement” then some of your colonies will automatically be set as Penal Colonies (policy = Enslave). Your other colonies with policy set to Resettle will migrate their unwanted races to the Penal
colonies for enslavement.
Steadily eliminates these races at the colony.
For each race that you are exterminating, the corresponding empires of those races will take deep offense at your actions. The amount of offense is directly related to the population amount that you exterminate. Exterminating races will also very negatively impact your empire’s reputation.
Source: Distant Worlds Legends manual