This work is part of A.I..d.-L.’s PhD on gene flow, demography and genetic diversity in maritime pine. S.C.G.-M. is working in population genetics and genomics of forest trees and conservation genetics of Mediterranean plants. G.G.V. is interested in conservation genetics, genetic structure studies and genomics of forest trees. E.H. is professor at the University of Valladolid, her research focuses on genetics of grapevine and forest trees. M.H. is interested in empirical and simulation studies of mating systems, gene flow and genetic structure in plants.
Spatial genetic structure in continuous and fragmented populations of Pinus pinaster Aiton
Article first published online: 29 SEP 2009
© 2009 Blackwell Publishing Ltd
Volume 18, Issue 22, pages 4564–4576, November 2009
How to Cite
DE-LUCAS, A. I., GONZÁLEZ-MARTÍNEZ, S. C., VENDRAMIN, G. G., HIDALGO, E. and HEUERTZ, M. (2009), Spatial genetic structure in continuous and fragmented populations of Pinus pinaster Aiton. Molecular Ecology, 18: 4564–4576. doi: 10.1111/j.1365-294X.2009.04372.x
- Issue published online: 3 NOV 2009
- Article first published online: 29 SEP 2009
- Received 10 December 2008; revision received 19 August 2009; accepted 25 August 2009
- forest fragmentation;
- genetic diversity;
- Iberian Peninsula;
- spatial genetic structure
Habitat fragmentation, i.e., the reduction of populations into small isolated remnants, is expected to increase spatial genetic structure (SGS) in plant populations through nonrandom mating, lower population densities and potential aggregation of reproductive individuals. We investigated the effects of population size reduction and genetic isolation on SGS in maritime pine (Pinus pinaster Aiton) using a combined experimental and simulation approach. Maritime pine is a wind-pollinated conifer which has a scattered distribution in the Iberian Peninsula as a result of forest fires and habitat fragmentation. Five highly polymorphic nuclear microsatellites were genotyped in a total of 394 individuals from two population pairs from the Iberian Peninsula, formed by one continuous and one fragmented population each. In agreement with predictions, SGS was significant and stronger in fragments (Sp = 0.020 and Sp = 0.026) than in continuous populations, where significant SGS was detected for one population only (Sp = 0.010). Simulations suggested that under fat-tailed dispersal, small population size is a stronger determinant of SGS than genetic isolation, while under normal dispersal, genetic isolation has a stronger effect. SGS was always stronger in real populations than in simulations, except if unrealistically narrow dispersal and/or high variance of reproductive success were modelled (even when accounting for potential overestimation of SGS in real populations as a result of short-distance sampling). This suggests that factors such as nonrandom mating or selection not considered in the simulations were additionally operating on SGS in Iberian maritime pine populations.