How did U. S. expansion to California affect most members of the Mexican aristocracy in the region?

They lost their land and forced into poverty.

Explanation:

The United States expansion in California began after the Mexican Cession taken by American by paying 15 million dollars to Mexico. The majority of the population in the Southwest were Spaniards. The Mexican aristocracy in the region were landowners who controlled the land and workers. California economy widely based on livestock and ranching. The old Spanish ranching families after the arrival of the Anglo newcomers lost their land and forced to live in poverty.