Genetic structure of fragmented polylepis multijuga plige (rosaceae) forests.

摘要

Polylepis multijuga is a threatened, endemic tree species in the northern Andes of Peru. P. multijuga is wind-pollinated which could allow for gene flow among fragments that would counteract drift and loss of genetic diversity. I collected samples from 371 trees in nine forest fragments and genotyped them at 316 AFLP loci. Genetic diversity (H = 0.131) was low compared to other species and genetic differentiation across all fragments was moderate (PhiPT = 0.14). Short distance (5-50m) genetic spatial autocorrelation within most fragments indicated short distance seed dispersal. Pair-wise genetic distance estimates between fragments (range: 0.036 -- 0.487) were not related to geographic distance and instead appeared to be related to habitat. The three most differentiated fragments, which also had the lowest genetic diversity values, were two small, high altitude fragments and a fragment located in a deep ravine suggesting that pollen flow does not effectively connect all fragments in this landscape.