Unidirectional hybridization at a species’ range boundary: implications for habitat tracking
Article first published online: 5 NOV 2009
© 2009 Blackwell Publishing Ltd
Diversity and Distributions
Volume 16, Issue 1, pages 1–9, January 2010
How to Cite
Beatty, G. E., Philipp, M. and Provan, J. (2010), Unidirectional hybridization at a species’ range boundary: implications for habitat tracking. Diversity and Distributions, 16: 1–9. doi: 10.1111/j.1472-4642.2009.00616.x
- Issue published online: 18 JAN 2010
- Article first published online: 5 NOV 2009
- Genetic assimilation;
- Pyrola grandiflora;
- Pyrola minor;
Aim Introgressive hybridization between a locally rare species and a more abundant congener can drive population extinction via genetic assimilation, or the replacement of the rare species gene pool with that of the common species. To date, however, few studies have assessed the effects of such processes at the limits of species’ distribution ranges. In this study, we have examined the potential for hybridization between range-edge populations of the wintergreen Pyrola minor and sympatric populations of Pyrola grandiflora.
Location Qeqertarsuaq, Greenland and Churchill, Manitoba, Canada.
Methods Genetic analysis of samples from Greenland and Canada was carried out using a combination of nuclear and chloroplast single nucleotide polymorphisms (SNPs).
Results Analysis of nuclear SNPs confirmed hybridization in populations of morphologically intermediate individuals, as well as revealing the existence of cryptic hybrids in ostensibly morphologically pure P. minor populations. Analysis of chloroplast SNPs revealed that this hybridization is unidirectional and suggests that hybrids originate via pollen swamping of P. minor by the more common P. grandiflora.
Main conclusions Extensive unidirectional hybridization may lead to the extinction of peripheral populations of P. minor where the two species grow sympatrically. Extinction could occur as a result of genetic assimilation where F1s are fertile, or via the removal of unidirectionally pollinated sterile F1s, or by a combination of these processes. This could compromise the ability of species to respond to climate change via habitat tracking, although the final outcome of these processes may ultimately depend on the rate of global climate change and its effect on the species’ distributions.