Cook's desert parsley occurs in two major population centers. In Jackson County, this species is found in the Agate Desert in vernal pools. These pools usually range from 3-100 feet across and no more than 12 inches deep. In Josephine County, this species is found in seasonally-wet, grassy meadows on alluvial floodplains in the Illinois Valley, with underlying soil forming clay pan.
Habitat loss and degradation have negatively impacted Cook's desert parsely. Conversion of habitat to agriculture or residential development, livestock grazing, road and powerline right-of-way maintenance (including herbicide spraying), off-road vehicle use, invasive plant infestations, mining, and fire suppression resulting in shrubland are among specific threats.
Conduct breeding system and seed production studies. Develop transplanting and/or introduction protocols.
Maintain current populations and restore vernal pool habitat at priority sites, including Denman Wildlife Management Area. Manage road construction and maintenance projects to avoid impacts to hydrology in and around known populations.