Answer:
The native population was lower than it really was in order for the conquerors to say they moved into a mostly uninhabited space and did not take it from anyone
Step-by-step explanation:
When conquerors describe the population of people they conquered, oftentimes they will distort facts by saying that the number of people there were smaller than they actually were to show that they really did not steal the land from them but merely moved into an unoccupied land.
This tactic is popular with known explorers and conquerors such as Christopher Columbus, Ferdinand Magellan, etc.