Vegetative Propagation Preserves Genomic Diversity and Informs Translocation Strategies in a Rare Clonal Plant

Conservation translocations are widely used to increase population size and redundancy, yet their genetic consequences are often uncertain, particularly for clonal species with unknown rates of sexual reproduction. Propagation through asexual reproduction is frequently employed in these systems, but its effectiveness for preserving genomic diversity remains poorly evaluated. We used genome-wide single nucleotide polymorphism (SNP) data to assess the genetic outcomes of translocation efforts in Pleuropogon oregonus, a critically endangered grass endemic to eastern Oregon, USA. We quantified genetic diversity, relatedness, and population structure across natural and introduced sites and used coalescent simulations to infer the divergence history between disjunct populations. Genetic analyses identified two divergent lineages corresponding to northern and southern regions, with divergence predating the last glacial period and limited subsequent gene flow. Within regions, natural populations exhibited high clonality but retained genetically distinct individuals. Introductions that used vegetative propagules from the northern region maintained heterozygosity and allelic diversity comparable to sources and captured multiple distinct genotypes, including alleles likely originating from an unsampled source, thereby increasing population redundancy. In contrast, the introduction derived from a low-diversity, southern region source reflected similarly limited clonal diversity. Our results demonstrate that vegetative propagation can effectively preserve genomic diversity in clonal species when propagules are sampled representatively, but that evolutionary history may inform sourcing and mixing decisions. More broadly, this study provides an empirical framework for integrating genomic data into conservation translocations, highlighting conditions under which vegetative propagation maintains evolutionary potential and when it may pose risks to long-term persistence.