Their Palo Alto City Council tenures may be coming to an end, but Karen Holman and Greg Scharff are preparing to square off in another competitive election this year, as each is looking to fill a seat on the Midpeninsula Regional Open Space District board of directors.

The two council members -- and ideological rivals -- are vying for the Ward 5 seat that for decades has been occupied by Nonette Hanko, a Palo Alto resident who in 1972 helped to found the district. Hanko's decision not to run for another term has created the opportunity for the two former mayors, each of whom joined the council in 2009 and who in many ways personify the city's ongoing debate over land use.

The ward includes East Palo Alto and portions of Menlo Park, Palo Alto and Stanford. Another former Palo Alto mayor, Yoriko Kishimoto, currently serves on the board and represents Ward 2, which encompasses Cupertino, Los Altos, Los Altos Hills and other portions of Palo Alto and Stanford.

As council members, Scharff and Holman have often clashed on policy issues, with Scharff generally voting along with the council's more developer-friendly side and Holman representing the slower-growth side.

Each candidate, however, believes she or he is perfectly suited to serving on the Open Space board. Scharff cites his years on other regional boards charged with protecting the environment and distributing funds to restoration projects. Holman points to her many years of advocating for environmental sustainability and open-space preservation, as well as her history of volunteering for the open-space district and her participation in shaping its vision.

Scharff is currently one of seven board members on the San Francisco Bay Area Restoration Authority, which raises and distributes funds for restoration projects around the San Francisco Bay. The authority in 2016 spearheaded Measure AA, a parcel tax that is projected to raise $25 million for shoreline projects in Santa Clara, San Mateo, Alameda, Contra Costa, Marin, Napa, Solano and Sonoma counties, as well as San Francisco.

Scharff also has been serving on the San Francisco Bay Conservation and Development Commission since 2013. He currently chairs the organization's five-member Enforcement Committee and serves as alternate to Santa Clara County Supervisor Dave Cortese.

Scharff, who pulled his papers to fill the seat on Friday, told the Weekly that he found his work on the two boards "very fulfilling." Joining the Midpeninsula Regional Open Space District, which in 2014 passed its own $300 million bond (also known as Measure AA), would provide him with an opportunity to make sure public money is well-spent, he said.

"I have a lot of experience and strong skills on the finance side, in making sure the projects get implemented and implemented in the right way," Scharff said.

While Scharff's decision to jump into the race is relatively recent, Holman has had her sights on the district seat for several years, ever since Hanko informed her that she would not be seeking another term and asked her to apply for her seat.

"I've always been an advocate for the environment, whether it's open space, marshland habitat, trees -- it's in my blood," Holman said. "Her asking me -- that was an honor."

A former Palo Alto planning commissioner and vociferous critic of new developments, Holman has years been involved in the Midpeninsula Regional Open Space District, having served on the Community Advisory Committee that helped the district establish its 2014 Vision Plan. She co-chaired the committee in 2015-16.

Holman has also served as the director of the Palo Alto History Museum and a board member of the Palo Alto Historical Association.

While the race is just heating up, both candidates are already enlisting supporters. Scharff, who has tighter alliances within the broader state Democratic Party, said he has already received the endorsements of Assemblyman Marc Berman, D-Palo Alto, and state Sen. Jerry Hill, D-San Mateo. Holman, who has strong support among neighborhood leaders and who has been a regular attendee at the district's retreats and annual lunches, said she has already received the endorsements of six of the seven current board members (all but Cecily Harris).

This will be the third time Holman and Scharff face off in an election. Both were victorious in 2009, when Holman finished second in a 14-candidate field with 7,688 votes and Scharff finished fifth with 5,939 votes, enough to secure the final open council seat. In 2014, Holman and Scharff finished first and second, respectively, with Holman picking up 11,281 votes to Scharff's 10,145.

Scharff said he wasn't aware that Holman was running when he decided to apply for the seat (because incumbent Hanko isn't running, the deadline for submitting the paperwork is this Wednesday). Holman, who pulled papers on July 19, submitted them to the district's clerk last Wednesday. She said that Scharff's late entry into the race doesn't dampen her enthusiasm for serving.

"It's work that I've been committed to for a long time," Holman said. His entry into the race "makes it harder, but it doesn't change anything."