Genetic monitoring of the eastern prairie fringed orchid ( <i>Platanthera leucophaea</i> ) demonstrates the positive impact of management practices over 17 years

Abstract Introduction The augmentation of small populations with individuals from other local sites is often proposed as a management tool to overcome the negative impacts of fragmentation but is rarely employed due to concerns of outbreeding depression. This hesitancy is compounded by the lack of examples with genetic monitoring over multiple generations needed to measure the impacts of genetic augmentation. Objectives This study assesses how seeding populations of Platanthera leucophaea (eastern prairie fringed orchid) have altered population genetic structure over multiple generations. Methods We compared DNA samples collected prior to 1998 and 17 years (2015) post seeding. These genetic data were paired with measurements of fruit set and seed viability to test for evidence of inbreeding depression. Results We found genetic management (the combined treatment of hand pollination and seed addition) leading to an increase in all measures of genetic variation. Populations with no genetic management or only population reinforcement via hand pollination had little to no change in genetic variation. Seed viability differed significantly among these populations, and results suggest hand pollination in combination with seed addition is likely to increase seed viability over time. We observed no difference between treatment types solely considering genetic status in 2015. Conclusions This work highlights the importance of genetic monitoring over time to accurately measure the impact of restoration work and offers the rare opportunity to assess a history of well‐documented restoration and management widely applicable to species facing reduced reproductive success in isolated habitats.