Genetic diversity in isolated patches of the tallgrass prairie forb, Lithospermum canescens (Boraginaceae)¹

Genetic diversity is not well understood for many species inhabiting isolated, fragmented systems. We evaluated genetic diversity for the mixed mating, native prairie forb, Lithosperum canescens (Michx) Lehm. (hoary puccoon), at an isolated tallgrass prairie site in southern Minnesota. Leaf tissue was collected from nearly all individuals inhabiting three disjunct patches and AFLP (amplified fragment length polymorphism) was performed on each individual. A high level of genetic diversity was maintained (Nei's Genetic Diversity, h = 0.31), and diversity was similar among the separate populations (H-T = 0.31, H-S =.30, G(ST) = 0.03) based on 73 scoreable bands from five primer pairs. Lithospermum canescens has retained a considerable amount of diversity among the three patches despite existing in isolated patches; pollination by flying insects likely contributed to the genetic similarities among the patches. Our results suggest that seeds from any one patch could be used for restoration of other suitable habitat on the reserve.