Simplify the following text for a Grade 12 native English-speaking person.
Original: Ethnographers and archaeologists now say that the introduction of diseases carried by European colonizers and the slave raiding , that devastated the population in the 1800s had a much greater social than environmental impact .
Simplified: Ethnographers and archaeologists also blame diseases carried by European colonizers and slave raiding of the 1860s for devastating the local peoples .