Why did Rio de Janeiro's economy decline near the end of the 18th century?

At the end of the 18th century, the economy of Rio de Janeiro—and that of the Brazilian colony as a whole—entered a period of crisis primarily due to two factors:

• Decline of Mining: The gold and diamond mining boom that had driven significant economic growth and migration during the 18th century began to taper off as the original deposits were depleted.12
• Market Competition: The region faced increasing competition from Central America in the world sugar market.1

These combined pressures were severe; by 1796, the value of exports passing through the port of Rio de Janeiro had fallen to less than half of the levels recorded in 1760. This economic downturn persisted until the early 19th century, when the arrival of the Portuguese royal family in 1808 and the expansion of coffee production helped restore prosperity to the region.13