Genetic Diversity and Population Dynamics Across Species Ranges

Genetic diversity and population dynamics across species ranges underpin the capacity of organisms to respond to environmental change, colonise new habitats and maintain long-term viability. Patterns of variation in allelic richness, heterozygosity and population differentiation emerge from interactions between historical biogeography, demographic processes and contemporary gene flow. Central populations often harbour greater overall diversity, whereas marginal or peripheral populations may exhibit reduced variation and increased genetic drift, a phenomenon captured by the centre–periphery hypothesis. However, ecological heterogeneity, isolation by distance and selection pressures can disrupt simple geographic trends, leading to unique adaptations or maladaptations at range edges. Integrating phylogeographic analyses, high-resolution genomic data and ecological niche modelling has revealed how past climate oscillations, landscape connectivity and habitat fragmentation shape both the distribution of genetic lineages and demographic history. These insights inform conservation strategies by identifying refugial areas, genetic hotspots and barriers to dispersal, thereby guiding efforts to preserve adaptive potential and mitigate the impacts of global change on species’ distributions.

Research from Nature Portfolio

A foundational study investigated an Asian temperate tree across its distribution by combining chloroplast and nuclear markers with ecological niche models. It revealed deep phylogeographic structuring linked to mountain refugia during glacial maxima and long-term demographic stability in central regions. Crucially, central populations supplied asymmetric gene flow towards marginal sites, suggesting that limited return flow may constrain adaptive expansion at range limits. Despite similar levels of neutral diversity between central and peripheral stands, this asymmetry in connectivity was proposed as a key factor shaping range dynamics and potential responses to future environmental shifts.

Genetic Diversity and Population Dynamics Across Species Ranges publication trend

The graph below shows the total number of articles in genetic diversity and population dynamics across species ranges across all publications each year (not limited to Nature Index journals).

Technical terms

Genetic diversity: The total variation in alleles and genotypes within and among populations of a species.

Population structure: The organisation of genetic variation across space, reflecting barriers to gene flow and historical processes.

Centre–periphery hypothesis: A model predicting higher genetic diversity at the centre of a species’ range and reduced diversity at its margins.

Gene flow: The movement of genes between populations through migration or dispersal, counteracting drift and divergence.

Phylogeographic structure: The spatial arrangement of genetic lineages shaped by past demographic events and landscape features.

References

1. Impacts of biogeographic history and marginal population genetics on species range limits: a case study of Liriodendron chinense. Scientific Reports (2016).
2. The genetic consequences of population marginality: A case study in maritime pine. Diversity and Distributions (2024).
3. Population genomics of flat‐tailed horned lizards (Phrynosoma mcallii) informs conservation and management across a fragmented Colorado Desert landscape. Molecular Ecology (2024).
4. Reduction of Genetic Variation When Far From the Niche Centroid: Prediction for Mangrove Species. Frontiers in Conservation Science (2022).