The figures — from Morning Consult’s Feb. 4-9, post-Iowa poll of 15,346 Democratic primary voters — illustrate the challenges facing candidates who hope to present themselves as a moderate alternative to Sanders.

Joe Biden has lost his national front-runner status to Sen. Bernie Sanders (I-Vt.) for the first time in Morning Consult’s weekly tracking of the Democratic presidential primary as former New York City Mayor Michael Bloomberg and former South Bend Mayor Pete Buttigieg of Indiana split key parts of the former vice president’s base of support.

Overall, Biden’s share of first-choice support fell 6 percentage points since before the Iowa caucuses, placing him at 22 percent, 3 points behind Sanders, who picked up 1 point over the same time period. Since Iowa, Bloomberg has seen his first-choice support jump 3 points, to 17 percent (third place), and Buttigieg rose 5 points to 11 percent.

Buttigieg is now tied with Sen. Elizabeth Warren (D-Mass.), who saw declines or no significant change across various demographic groups and whose first-choice support fell 3 points since the pre-Iowa survey, which was conducted Jan. 27-Feb. 2. Both polls had a 1-point margin of error.

Increases in support across the board for Bloomberg, who is not competing in nominating contests until Super Tuesday, were more incremental, while Buttigieg’s bumps were more dramatic, a reflection of the momentum following his narrow victory in Iowa, as detailed by the Iowa Democratic Party’s count of state delegate equivalents, but also his lower share of support heading into the caucuses.

Among liberal, moderate and conservative Democratic voters, Buttigieg effectively doubled his support, while Bloomberg saw more modest gains. Sanders solidified his support among the party’s most liberal voters, while Bloomberg improved his standing among moderates and conservatives, though he’s still behind Biden.