Genetic variation and demographic contraction of the remnant populations of Mexican Caribbean pine (Pinus caribaea var. hondurensis: Pinaceae)

摘要

Introduction The recognition of endangered species takes into account geographic isolation and small size of populations, as is the case of two populations of Pinus caribaea var. hondurensis distributed in Mexico.Materials and methods This study evaluates the genetic variation within and among Mexican populations of P. caribaea var. hondurensis to make inferences on the historical dynamics of the populations by screening a total of 69 trees with six nuclear microsatellites.Results The results indicate intermediate levels of genetic variation in both populations (H-E = 0.465). The level of inbreeding was significant for both populations (Caobas F-IS = 0.097; Pioneros F-IS = 0.163), but the effective population size was higher in the Pioneros population (N-e = 868) compared to Caobas (N-e = 402). Average genetic differentiation was low (R-ST = 0.033) and historical migration rate was relatively high (M = 13.2).Discussion These results, together with the analysis of bottlenecks, provide us evidence of historical events of contraction of the population size, which probably occurred between 8,100 and 35,000 years ago. We propose conservation strategies for the emergent recovery of these remaining native forest patches.