Complex sentence: As a consequence, San Diego had experienced negative net migration since 2004, with a significant number of people moving to Riverside County, with many residents commuting daily from Temecula and Murrieta, to their jobs in San Diego.
Split into simpler sentences: As a consequence, San Diego experienced negative net migration since 2004. A significant number of people moved to adjacent Riverside County, commuting daily from Temecula and Murrieta to jobs in San Diego.