Final answer:
Spanish landowners in the Caribbean replaced the rapidly declining Indian population with African slaves to maintain labor on sugar plantations, adapting the economy in the West Indies.
Step-by-step explanation:
As diseases caused the rapid decline of Indians, especially in the Caribbean islands, Spanish landowners replaced the Indian farm workers with African slaves. The indigenous populations suffered massive losses due to diseases such as smallpox and influenza, for which they had no immunity, leading to a dire shortage of labor on plantations.
Jesuits petitioning to improve the treatment of the indigenous people, combined with the high mortality rate from diseases, influenced the shift to the importation of African slaves. These Africans had developed some immunity to European diseases and were forced into slavery, primarily to work on sugar plantations in locations like Hispaniola, where the native TaĆno population had all but vanished due to violence, enslavement, and disease.
This replacement of Indian labor with African slaves became a central component of the colonial economy in the West Indies.