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ABSTRACT In integrative distributional, demographic and coalescent (iDDC) modelling, a critical component is the statistical relationship between habitat suitability and local population sizes. This study explores this relationship in twoEnyaliuslizard species from the Brazilian Atlantic Forest: the high‐elevationE. iheringiiand low‐elevationE. catenatusand how this transformation affects spatiotemporal demographic inference. Most previous iDDC studies assumed a linear relationship, but this study hypothesises that the relationship may be nonlinear, especially for high‐elevation species with broader environmental tolerances. We test two key hypotheses: (1) The habitat suitability to population size relationship is nonlinear forE. iheringii(high‐elevation) and linear forE. catenatus(low‐elevation); and (2)E. iheringiiexhibits higher effective migration across populations thanE. catenatus. Our findings provide clear support for hypothesis (2), but mixed support for hypothesis (1), with strong model support for a nonlinear transformation in the high‐elevationE. iheringiiand some (albeit weak) support for a nonlinear transformation also inE. catenatus. The iDDC models allow us to generate landscape‐wide maps of predicted genetic diversity for both species, revealing that genetic diversity predictions for the high‐elevationE. iheringiialign with estimated patterns of historical range stability, whereas predictions for low‐elevationE. catenatusare distinct from range‐wide stability predictions. This research highlights the importance of accurately modelling the habitat suitability to population size relationship in iDDC studies, contributing to our understanding of species' demographic responses to environmental changes.
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Hybrid Zone Analysis Using Coalescent‐Based Estimates of Introgression and Migration in Plateau Fence Lizards ( Sceloporus tristichus )
ABSTRACT Coalescent modelling of hybrid zones can provide novel insights into the historical demography of populations, including divergence times, population sizes, introgression proportions, migration rates and the timing of hybrid zone formation. We used coalescent analysis to determine whether the hybrid zone between phylogeographic lineages of the Plateau Fence Lizard (Sceloporus tristichus) in Arizona formed recently due to human‐induced landscape changes, or if it originated during Pleistocene climatic shifts. Given the presence of mitochondrial DNA from another species in the hybrid zone (Southwestern Fence Lizard,S. cowlesi), we tested for the presence ofS. cowlesinuclear DNA in the hybrid zone as well as reassessed the species boundary betweenS. tristichusandS. cowlesi. No evidence ofS. cowlesinuclear DNA is found in the hybrid zone, and the paraphyly of both species raises concerns about their taxonomic validity. Introgression analysis placed the divergence time between the parental hybrid zone populations at approximately 140 kya and their secondary contact and hybridization at approximately 11 kya at the end of the Pleistocene. Introgression proportions estimated for hybrid populations are correlated with their geographic distance from parental populations. The multispecies coalescent with migration provided significant support for unidirectional migration moving from south to north, which is consistent with spatial cline analyses that suggest a slow but steady northward shift of the centre of the hybrid zone over the last two decades. When analysing hybrid populations sampled along a linear transect, coalescent methods can provide novel insights into hybrid zone dynamics.
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- PAR ID:
- 10617260
- Publisher / Repository:
- Molecular Ecology
- Date Published:
- Journal Name:
- Molecular Ecology
- Volume:
- 34
- Issue:
- 13
- ISSN:
- 0962-1083
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1111/mec.17819
