Data from: Habitat differences influence genetic impacts of human land-use on American beech (Fagus grandifolia)

Natural reforestation after regional forest clearance is a globally common land-use sequence. The genetic recovery of tree populations in these re-colonized forests may depend on the biogeographic setting of the landscape, for instance whether they are in the core or marginal part of the species' range. Using data from 501 individuals genotyped across seven microsatellites, we investigated whether regional differences in habitat quality affected the recovery of genetic variation in a wind-pollinated tree species, American beech (Fagus grandifolia) in Massachusetts. We compared populations in forests that were re-colonized following agricultural abandonment to remnant forests that have only been logged in both central inland and marginal coastal regions. Across all populations in our entire study region, re-colonized forests show limited reduction of genetic diversity as only observed heterozygosity was significantly reduced in these forests (HO = 0.520 and 0.590, respectively). Within inland region, this pattern was observed while in the coast, re-colonized populations exhibit no reduction in all genetic diversity estimates. However, genetic differentiation among re-colonized populations in marginal coastal habitat increased (Fst logged = 0.072; Fst secondary = 0.249), with populations showing strong genetic structure, in contrast to inland region. These results indicate that the magnitude of recovery of genetic variation in re-colonized populations can vary at different habitats.