User blog comment:James12708/Possibility of a Mass Effect 4/@comment-78.8.159.217-20130430071430/@comment-8419211-20130430212633

all salarians colonies were far from the spiral arms of the Milky Way galaxy. so colonies which were located on this arms were harvested ( batarians were harvested, geth were modified, vorcha was just cut off from other civilizations, reapers not harvested them, just reduce help possibilities from them) Also, reapers jumped from batarian system to solar system using relay twice (so just 2 jumps). All relay system which lead to salarians colonies were not fully conquered by reapers before battle for the Earth and reapers never send their fleets to others system if current system was not conquered. so, Salarians survived cuz their systems were more close to the galaxy center than other.