By Anthony Boadle
BRASILIA (Reuters) - Brazilian President Dilma Rousseff has gained some ground against opposition candidate Marina Silva whose surge in voter support for the October elections has ended, two new polls showed on Wednesday.
Both polls still project the popular environmentalist as the favorite to beat Rousseff in a second-round runoff, though by a narrower margin than surveys done last week.
The numbers appear to show Rousseff's attacks on Silva, launched in a presidential debate on Monday, are beginning to pay off, while campaign mistakes by Silva could have halted her meteoric rise since entering the race just two weeks ago.
According to the survey by polling institute Ibope, Rousseff picked up three percentage points in voter support for the Oct. 5 election, and her government's approval rating rose two percentage points to 36 percent, welcome news for a president who appeared to be against the ropes.
Polling firm Datafolha confirmed that Rousseff's bleeding has stopped, with her support rising one percentage point to 35 percent since last week, while Silva remained at 34 percent.
Silva is still projected to win the expected Oct. 26 runoff by 48 percent against 41 percent for Rousseff, a margin that has narrowed from 10 points last week, Datafolha said.
Silva was thrust into the election race when her party's candidate Eduardo Campos was killed in a plane crash.
A popular anti-establishment figure, she is threatening to end the 12-year rule of the Workers' Party in the election, which is being watched closely by investors hoping that a change of government will bring more market-friendly policies that can stir an economy that slipped into recession this year.
In a first-round vote, support for Rousseff rose to 37 percent from 34 percent in the previous poll, while Silva's support rose to 33 percent from 29 percent, Ibope said. Support for market favorite Aecio Neves, who was pushed into third place by Silva, has fallen to 15 percent from 19 percent.
In other good news for Rousseff, the president's rejection rate, or the percentage of voters who say they would never vote for her, fell to 31 percent from 36 percent last week.
Silva's rejection rate is much lower, but rose slightly to 12 percent from 10 percent in the previous poll, Ibope said.
That would indicate that Silva has not suffered significant damage from two embarrassing revisions to her party platform that withdrew support for nuclear energy and same-sex marriage.
The commitment to back legislation for gay marriage was dropped after an uproar by evangelical pastors that threatened to undermine support for Silva, a fervent Pentecostal Christian, among a growing religious constituency.
Silva, who vows to clean up Brazil's discredited political establishment, has also been dogged by media reports that allege the plane that crashed with Campos on board was acquired in a shady campaign donation of the kind that she has denounced.
Both polls were carried out Sunday through Tuesday. Ibope surveyed 2,506 voters and Datafolha polled 10,054. The polls have a margin of error of two percentage points. The results were posted on the websites of the O Estado de S. Paulo and Folha de S.Paulo newspapers.
(Additional reporting by Silvio Cascione; Editing by G Crosse, Dan Grebler and Lisa Shumaker)