Complex sentence: Within British Columbia, the turtle's range is not continuous and can better be understood as northward extensions of the range from the United States; high mountains present barriers to east-west movement of the turtles within the province or from Alberta.
Split into simpler sentences: Within British Columbia, the turtle's range is not continuous and can better be understood as northward extensions of the range from the United States. High mountains present barriers to east-west movement of the turtles within the province or from Alberta.