Abstract
BackgroundGeographic ranges of ectotherms such as reptiles may be determined strongly by abiotic factors owing to causal links between ambient temperature, juvenile survival and individual sex (male or female). Unfortunately, we know little of how these factors interact with dispersal among populations across a species range. We used a simulation model to examine the effects of dispersal, temperature-dependent juvenile survival and sex determining mechanism (temperature-dependent sex determination (TSD) and genotypic sex determination (GSD)) and their interactions, on range limits in populations extending across a continuous range of air temperatures. In particular, we examined the relative importance of these parameters for population persistence to recommend targets for future empirical research.ResultsDispersal influenced the range limits of species with TSD to a greater extent than in GSD species. Whereas male dispersal led to expanded species ranges across warm (female-producing) climates, female dispersal led to expanded ranges across cool (male-producing) climates. Two-sex dispersal eliminated the influence of biased sex ratios on ranges.ConclusionThe results highlight the importance of the demographic parameter of sex ratio in determining population persistence and species range limits.
Highlights
Geographic ranges of ectotherms such as reptiles may be determined strongly by abiotic factors owing to causal links between ambient temperature, juvenile survival and individual sex
We explore the role of dispersal in determining the extent of population persistence and range limits in species of reptiles with the common temperaturedependent sex determination (TSD) pattern 1A and compare it to results for species with genotypic sex determination (GSD)
Female dispersal can either enhance or diminish persistence near the edge of the range depending on how many females leave these populations and whether juvenile survival at the new population is high enough to provide a local supply of males
Summary
Geographic ranges of ectotherms such as reptiles may be determined strongly by abiotic factors owing to causal links between ambient temperature, juvenile survival and individual sex (male or female). The role of temperature in demography and range limits may be especially important for species with temperaturedependent sex determination (TSD; [12,13]). In these species, individual sex (male or female) is permanently determined during embryonic development by incubation temperature [14]. There has been at least one attempt to explain the geographical distribution of TSD species based on sex ratios, suggesting that imbalanced sex ratios (and marginal habitats) limit population growth at range boundaries [13]. It was proposed that balanced sex ratios are located at range centres (or favourable habitats), and skewed sex ratios at more marginal habitats [13]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
