Final answer:
American officials were concerned about the expansion of Indian trading networks and overhunting of bison.
Step-by-step explanation:
American officials were especially concerned about the expansion of Indian trading networks, as it allowed for increased interaction and potential alliances among Native American tribes. This posed a threat to American control and dominance over the Southwest. Additionally, officials were also concerned about the overhunting of bison by the Southwest Indians, as it threatened the stability of the region's ecosystem and the livelihood of settlers who relied on bison for various resources. The spread of Indian diseases and slave taking were not specifically mentioned as concerns of American officials in relation to the Southwest Indians.
Learn more about concerns of American officials regarding the practices of Southwest Indians