Journal of Heredity Advance Access published online on December 7, 2006
Journal of Heredity, doi:10.1093/jhered/esl058
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Population Growth Confounds Phylogeographic Inference in Namaqua Sandgrouse
From the DST-NRF Centre of Excellence at the Percy FitzPatrick Institute, Molecular Ecology and Evolution Programme, Department of Genetics, University of Pretoria, Pretoria 0002, South Africa (Delport and Bloomer); and the DST-NRF Centre of Excellence at the Percy FitzPatrick Institute of African Ornithology, University of Cape Town, Rondebosch 7701, South Africa (Crowe and Lloyd). Wayne Delport is now at room 2.04, John Day Zoology Building, University Avenue, University of Cape Town, Rondebosch, Cape Town, 7701, South Africa
Address correspondence to W. Delport at the address above, or e-mail: wdelport{at}botzoo.uct.ac.za.
The Namaqua sandgrouse, Pterocles namaqua, is a highly nomadic granivore of semiarid to arid habitats. As a result of nomadic movements in response to rainfall, the size of the breeding population in any one area fluctuates dramatically between breeding seasons. This high mobility in response to spatial and temporal abundance of food resources is expected to result in little population genetic structuring. Namaqua sandgrouse also shows a seasonally predictable partial migration between the southeast and northwest regions of South Africa, and a further possible north–south migration between southwestern South Africa and central Namibia. It is unclear whether birds migrating between these regions breed in only one or both regions. If populations breed in only one region of their migratory range, then population genetic structuring is predicted to occur. This study addresses Namaqua sandgrouse movements with the analysis of mitochondrial DNA control region sequences. In general, little population genetic structure was evident, yet strong signals of population growth were detected. Several populations have private alleles, which is in direct contradiction to the spatial genetic pattern expected under high levels of gene flow. We suggest that the inference of high levels of female gene flow could be an artifact of population growth and that additional loci will allow a greater understanding of Namaqua sandgrouse movements.