Scott Rutledge, the league's executive director, said conservationists "scored big" as far-reaching bills dealing with renewable energy, energy and water conservation and mercury pollution were passed and signed by Gibbons.

"On the important issues highlighted in these votes, it is clear that the environment won in 2007," Rutledge added.

Democrats tended to rank higher than Republicans in the report, with Assembly Democrats and their leaders at the top, followed by Assembly Republicans with a 92 percent average, Senate Democrats with an 83 percent average and Senate Republicans at 75 percent.

Assembly Transportation Chairman Kelvin Atkinson, D-North Las Vegas, had a 100 percent score but still made the "dirty deeds" list for failing to conduct a hearing on a measure to reduce greenhouse gas emissions by upgrading vehicle tailpipe emission standards.

Also on that list were Sens. Mark Amodei, R-Carson City, and Maurice Washington, R-Sparks, both with 75 percent scores.

Amodei delayed a bill dealing with mercury pollution, although it eventually passed, and Washington tried to tie funding for new schools to a development bill, the league said.

While Gibbons got a C-minus, the league, which had given him zero scores in two earlier reports while he was in Congress, said the GOP governor signed several key natural resource bills and "has shown himself to be receptive to conservation issues."

However, the league said Gibbons vetoed one bill to help expand use of solar panels, didn't join the Western Climate Initiative endorsed by most other neighboring governors and has continued to support construction of coal-fired power plants in Nevada.

"Given that burning coal is the top contributor to carbon dioxide emissions in the United States, it is irresponsible for our state to support further development of coal at the expense of our renewable resources," the report states.