How did Spain’s policies "destabilize the plantation economy of the British colonies"?

"The Spanish intended to destabilize the plantation economy of the British colonies by creating a community that would attract slaves seeking escape and refuge. Word of the free black settlement reached the Province of South Carolina; it is believed to have helped inspire the Stono Rebellion in September 1739."

Explanation:

answer: the apache, comanche, kiowa, crow, and osage tribes are plains indians.  

b.   jim crow laws were enacted in northern states.