SACRAMENTO  (AP) — Former state assemblyman Jim Nielsen has been sworn in as the new state senator representing a broad swath of rural Northern California.

The Republican from Gerber took office Thursday, two days after he won two-thirds of the vote in a special election in the GOP-leaning 4th Senate District.

He pledged to concentrate on improving California's business climate while opposing a 14-month-old law that is sending lower-level criminals to county jails instead of state prisons.

Nielsen has been a leading critic of Democratic Gov. Jerry Brown's program to reduce prison crowding and spending.

He replaces Republican Doug La Malfa, who was elected to Congress with two years remaining in his state Senate term.

The district includes all or parts of 12 counties, from north of Sacramento to the Oregon border.