it depends. In my opinion, each case/ impact is individual while some cases might impact negatively the native american [ in reservation? born in US? or to which extent native?], others might impact them in a positive way

The existence of individual cases does not negate the fact that a systemic effect exists. What is that systemic effect?

there is certain good in diversity which comes from immigrants from different locations altogether with skills and natural resources it was a factor that allowed US to build the most powerful economy in the world. However, times change. I remember from lessons of History in the Univesity that every civilization has phases: Establishing, Prosperity, Decay. It is obvious that average impact at each of the three phases might be different. Also it might be that in the North and in the South the impact is opposite.

Are you an American politician or a practicing immigration attorney?