Seed collected from two element occurrences (Railroad and Downs Prairie) in eastern Arkansas (2010) are conserved in the Missouri Botanical Garden seed bank.

Known from about 20 occurrences in Arkansas and Louisiana in remnant prairies and roadsides. Historic occurrences in Texas. During the most recent survey at several sites, plants were not found. Historically, much of the species habitat is lost through the conversion of prairie to cropland. Threats include road maintenance, herbicide drift, additional land conversion, and poor management.

According to NatureServe (2009), the following threats apply to prairie evening primrose: Habitat loss due to conversion of remnant prairies to cropland. Disturbance from maintenance activities in utility, railroad, and highway rights-of-ways. H

Known from only about 20 occurrences, prairie evening primrose is rapidly declining in the wild due primarily to conversion of prairie habitat to cropland and possible improper management practices. In Arkansas, five occurrences in remnant prairies are protected by the Arkansas Natural Heritage Commission. Occurrences in the Grand Prairie of Arkansas are often located in rights-of-ways where maintenance disturbance potentially threatens the populations. Only about 600 acres of remnant prairie remains in east-central Arkansas, indicating little potential for discovery of new populations unless more occurrences are found in willow-oak flatwoods of the Gulf Coastal Plain. Populations in Arkansas are currently small and have declined in abundance over the past decade (Theo Witsell, Botanist, Arkansas Natural Heritage Program, May 2010). Arkansas: 12 counties (Arkansas, Clay, Drew, Hot Spring, Lafayette, Little River, Lonoke, Monroe, Prairie, Pulaski, St. Francois, and Yell). Most collections are historical have not been recently assessed. Louisiana: 5 counties, (Bossier, Jefferson Davis, Morehouse, Rapides, and Tensas). Status is unknown at most sites. Texas: 1 site, Galveston County, Texas (historical)

Current research is focusing on the taxonomic status of the species using genetic analysis, and defining the pollination and breeding systems through field and greenhouse studies (Kyra Krakos, Graduate Student, Washington University, personal communication).

Management of remnant prairie habitat in the Grand Prairie varies according to landownership. Prairie evening primrose populations on private property are typically managed with summer mowing (haying) (NatureServe 2009). Natural areas in the Grand Prairie are now managed with prescribed fire but used to be managed with summer haying (Theo Witsell, Botanist, Arkansas Natural Heritage Program, May 2010). Frequent spring burns may have caused a decline in the abundance of prairie evening primrose, which like other spring forbs, may benefit from summer haying (Theo Witsell, Botanist, Arkansas Natural Heritage Program, May 2010). One hypothesis is that prairie evening primrose requires unplowed prairies and recurrent management to thwart succession (NatureServe 2009). Prairie mounds, which are indicators of unplowed prairies, are found in at least two natural occurrences (Downs and Roth Prairies, Arkansas County, Arkansas) of prairie evening primrose (GHF 2010). Currently, there are no best management practice plans for the species.

Quantitative population dynamics studies are urgently needed to understand the response of prairie evening primrose populations to management practices in remnant prairies. Life-history studies are needed to understand the ecological factors that promote seedling recruitment and maintenance of reproductive individuals in the populations. Distributional surveys are needed to determine: 1) whether the taxa persists at historical sites, and 2) whether it occurs more broadly in willow oak flatwoods along the Gulf Coastal Plain or is restricted primarily to remnant tallgrass prairie sites in the Grand Prairie.

Seed collected from two element occurrences (Railroad and Downs Prairie) in eastern Arkansas (2010) are conserved in the Missouri Botanical Garden seed bank. Propagation protocols are needed to grow plants from seed to maturity for life-history study and to develop ex situ population seed sources. Given the rarity of the species, experimental reintroductions into remnant tallgrass prairies may be warranted once best habitat management practices are determined.