Population genetics, demographic and evolutionary history of the Dudley’s lousewort (Pedicularis dudleyi), a rare redwood forest specialist

• Published in: Conservation genetics 2022-06, Vol.23 (3), p.513-525
• Main Authors: Misiewicz, Tracy M., Hauser, Christopher, Carter, Benjamin E.
• Format: Article
• Language: English
• Subjects: 20th century; Animal Genetics and Genomics; Biodiversity; Biomedical and Life Sciences; Conservation Biology/Ecology; Demographics; Demography; Ecology; Endemic plants; Environmental degradation; Evolutionary Biology; Evolutionary genetics; Genetic analysis; Genetic diversity; Genetic structure; Genetics; Geographical distribution; Habitat loss; Hypotheses; Life Sciences; Logging; Morphology; Natural populations; Pedicularis dudleyi; Plant Genetics and Genomics; Population genetics; Population structure; Populations; Research Article; Single-nucleotide polymorphism; Species; Species diversity; Wildlife conservation
• ISSN: 1566-0621; 1572-9737
• DOI: 10.1007/s10592-022-01433-x

Pedicularis dudleyi (Dudley’s Lousewort, Orobanchaceae) is an extremely rare plant endemic to the redwood forests of Central California. Until recently, the species was known only from three extant natural populations. However, in 2019, one of those populations was described as a novel species ( P. rigginsiae D.J. Keil) based on morphological and ecological data leaving only two populations described as P. dudleyi . While little is known about the past distribution of the species, historical records have led to speculation that the species was once more widespread and may have suffered from habitat destruction as a result of widespread logging during the early twentieth century. We utilized a combination of ddRAD SNP and Sanger sequencing data to: (1) Test the morphological hypothesis that P. rigginsiae is distinct from P. dudleyi ; (2) Describe the genetic diversity and population structure of P. dudleyi and; (3) Test the hypothesis that the species underwent a bottleneck corresponding with increased logging of redwood forests in the early twentieth century. Our results support the recognition of P. rigginsiae as distinct from P. dudleyi , increasing the conservation priority of both species. Genetic diversity statistics and analyses of genetic structure suggest that both populations of P. dudleyi are highly differentiated from each other with one population exhibiting unexpected substructure. Finally, demographic modeling supports a scenario where the contemporary rarity of the species is explained by a recent bottleneck.