Complex sentence: The Métis Settlements consist of Indigenous Métis populations unique from the Red River Métis Populations, however following the Riel Rebellions some Red-River Métis fled westward, marring into the contemporary Métis Settlement populations.
Split into simpler sentences: The Métis settlements consist of indigenous Métis populations unique from the Red River Métis Populations. However, following the Riel Rebellions some Red-River Métis fled westward, marrying into the contemporary Métis settlement populations.