How do climate-linked sex ratios and dispersal limit range boundaries?

Area of Science:

• Ecology
• Evolutionary Biology
• Climate Change Biology

Background:

• Abiotic factors, particularly ambient temperature, strongly influence reptile geographic ranges.
• Temperature affects juvenile survival and individual sex determination, with implications for population dynamics.
• Limited understanding exists on how dispersal interacts with these factors across species ranges.

Purpose of the Study:

• To investigate the effects of dispersal, temperature-dependent juvenile survival, and sex determination mechanisms on species range limits.
• To examine the interactions between these factors in populations across a continuous temperature gradient.
• To identify key parameters for population persistence and guide future empirical research.

Main Methods:

• Utilized a simulation model to explore population dynamics.
• Incorporated temperature-dependent sex determination (TSD) and genotypic sex determination (GSD) mechanisms.
• Analyzed the influence of dispersal (male, female, and two-sex) on range limits under varying temperatures.

Main Results:

• Dispersal had a greater impact on range limits for species with TSD compared to GSD.
• Male dispersal expanded ranges in warm climates, while female dispersal expanded ranges in cool climates.
• Dispersal involving both sexes mitigated the effects of biased sex ratios on species ranges.

Conclusions:

• Sex ratio is a critical demographic parameter influencing population persistence.
• The interplay between dispersal and sex determination mechanisms shapes species range limits.
• Findings underscore the importance of considering these factors in ecological and conservation studies.