| Leedy's roseroot (Rhodiola integrifolia ssp. leedyi) is an endangered plant native to Minnesota, New York, and South Dakota. It is on the Minnesota and New York endangered and the U.S. federal threatened species lists. The only known occurrences of Leedy's roseroot are in four populations in Minnesota (three of which are within the Root River watershed), two populations in New York state, and a single population in South Dakota. Due to the rarity of Leedy's roseroot, little is known about its current population dynamics and genetic parameters. In this study, I used nine microsatellite markers to estimate the effective population sizes (Ne), gene flow among populations, and levels of inbreeding of three Leedy's roseroot populations in Minnesota and one in New York. These parameters can be used to estimate the rates of loss of genetic variability, and along with field-based demographic data, can be used to identify management units, judge whether an individual population requires intervention, and to develop any recommended conservation actions. I analyzed DNA samples of 134 individuals from one NY and three MN Leedy's roseroot populations. I found that 7 of the 9 loci were polymorphic, with a total of 21 alleles. The expected heterozygosity (He) across loci ranged from 0 to 0.49, with a mean of 0.27. The observed heterozygosity (Ho) across loci ranged from 0 to 0.72, with a mean of 0.38. Population NY, the numerically largest, had the second highest number of alleles and the highest He and Ho values (0.32 and 0.50, respectively). Population MN3, the smallest population, had the second-highest number of alleles, was polymorphic at seven loci, and had the second highest He and Ho values (0.30 and 0.36, respectively). Population MN1, largest of the Minnesota populations, had low heterozygosity but was the most stable. The pairwise FST values ranged from 0.07 to 0.25, with a mean of 0.18. The results showed significant genetic differentiation among the populations and relatively low genetic diversity within the populations. Conservation efforts should focus on preserving the remaining genetic diversity of populations NY, MN1, and MN3 through in situ and ex situ strategies. |
