This statement describes a push factor.
A push factor refers to a factor or incentive that encourages individuals or groups to leave their current location or situation. In this case, the Mexican government felt threatened by the native groups and worried about the potential loss of Texas to the United States. To address these concerns, the Mexican government initiated policies to move more settlers into the region. The push factor, in this case, is the fear of losing control and feeling threatened by external forces, prompting the government to take action to strengthen its presence in the area.