Ingrid Visseren-Hamakers

Visseren-Hamakers held academic positions at Wageningen University and George Mason University in the United States, before joining Radboud University in 2019.^[3] Between 2016 and 2019, she served as coordinating lead author for the global assessment report of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES).^[3]

Her political career began in Rotterdam, where she was a member of the IJsselmonde borough council from 1998 to 2002, on behalf of GroenLinks.^[3] From 2004 to 2007, she served in the party's executive board.^[3] She later joined the Party for the Animals (PvdD), and was elected as a member of the Senate in the 2023 election. On 3 February 2025, she succeeded Niko Koffeman as leader of the PvdD Senate group.^[4]

On 10 November 2025, it was announced that Visseren-Hamakers had left the PvdD Senate group, forming her own independent group.^[5] The split followed an internal dispute, after Niko Koffeman had resigned his party membership on 21 October 2025, citing dissatisfaction with the party's political direction.^[6] He was supported by fellow senator Peter Nicolaï.^[7] As a result, Koffeman and Nicolaï continued together under the party banner, while Visseren-Hamakers formed a separate group.^[8] Despite the formal split, Visseren-Hamakers is regarded by the Party for the Animals as the sole legitimate representative of the party in the Senate.^[8]