Reproductive biology, genetic variation and conservation of the rare endemic dysploid Delphinium bolosii (Ranunculaceae)

Abstract

Delphinium bolosii C. Blanché and Molero (Ranunculaceae), is a very rare endemic plant known from only two populations in Catalonia, having fewer than 1500 individuals. A biological survey of this species included: (a) reproductive biology, comprising pollination ecology, breeding systems, seed set and pollen viability; and (b) enzyme electrophoresis to measure genetic variation within and between two populations. A trend to increasing self-pollination rates (up to 20%) and to low levels of genetic variation (1.6–1.7 alleles per locus), together with high rates of nectar robber visits are reported. The hypothetic evolutionary relationships (chromosomal changes and geographic isolation) of this species with its related widespread ancestor Delphinium fissum are also discussed. The main threats to this species are catastrophic events (especially as soil erosion), human impact activities (both agriculture and tourism) and decreasing pollination. The small populations and low genetic variation reinforce its endangered status. Some conservation measures are suggested, including in-situ and ex-situ strategies.