American River Bankshares, the parent of American River Bank, earned $870,000 in the fourth quarter, down from earning $1 million in the same period n 2011. For the full year, American River (NASDAQ: AMRB) earned $3.2 million, up from earning $2.5 million in 2011. “This past year has been one of mixed results, with a 28 percent increase in profits and a 52 percent higher share price,” said David Taber, President and CEO of American River Bankshares. “We were also able to reduce nonperforming…