Density‐dependent fitness, not dispersal movements, drives temporal variation in spatial genetic structure in dark‐eyed juncos (Junco hyemalis)
Abstract
Some studies have found that dispersal rates and distances increase with density, indicating that density‐dependent dispersal likely affects spatial genetic structure. In an 11‐year mark–recapture study on a passerine, the dark‐eyed junco, we tested whether density affected dispersal distance and/or fine‐scale spatial genetic structure. Contrary to expectations, we found no effect of predispersal density on dispersal distance or the proportion of locally produced juveniles returning to the population from which they hatched. However, even though density did not affect dispersal distance or natal return rates, we found that density still did affect spatial genetic structure. We found significant positive spatial genetic structure at low densities of (postdispersal) adults but not at high densities. In years with high postdispersal (adult) densities that also had high predispersal (juvenile) densities in the previous year, we found negative spatial genetic structure, indicating high levels of dispersal. We found that density also affected fitness of recruits, and fitness of immigrants, potentially linking these population parameters with the spatial genetic structure detected. Immigrants and recruits rarely nested in low postdispersal density years. In contrast, in years with high postdispersal density, recruits were common and immigrants had equal success to local birds, so novel genotypes diluted the gene pool and effectively eliminated positive spatial genetic structure. In relation to fine‐scale spatial genetic structure, fitness of immigrants and new recruits is poorly understood compared to dispersal movements, but we conclude that it can have implications for the spatial distribution of genotypes in populations.
Faculty Members
- Ellen D. Ketterson - Department of Biology Indiana University Bloomington Indiana
- Nicole M. Gerlach - Department of Biology University of Florida Gainesville Florida
- Eric B. Liebgold - Department of Biological Sciences Salisbury University Salisbury Maryland
Themes
- Spatial genetic structure
- Population dynamics
- Density-dependent dispersal
- Genetic diversity
- Fitness of recruits and immigrants
Categories
- Ecology
- Ecology and evolutionary biology
- Geosciences, atmospheric, and ocean sciences
- Marine sciences
- Biological and biomedical sciences
- Geological and earth sciences nec
- Genome sciences and genomics
- Genetics and genomics
- Genetics, general
- Ocean marine sciences and atmospheric science
- Geology earth science, general
- Marine biology and biological oceanography
- Geological and earth sciences
- Ecology, evolutionary biology, and epidemiology
- Evolutionary biology
- Molecular genetics