Sex Ratio Bias Triggers Demographic Suicide in a Dense Tortoise Population
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View abstract on PubMed
Summary
This summary is machine-generated.In a dense tortoise population, a skewed sex ratio and coercive mating are causing an extinction vortex. This study documents the first wild extinction event driven by mating system collapse.
Area Of Science
- Ecology
- Conservation Biology
- Animal Behavior
Background
- Biased adult sex ratios and high population densities in coercive mating systems can theoretically trigger extinction vortices.
- This phenomenon has not been previously documented in wild populations.
Purpose Of The Study
- To document the first wild extinction event caused by a coercive mating system.
- To investigate the impact of biased sex ratios and high population densities on a tortoise population.
Main Methods
- Utilized 16 years of capture-recapture data from an island population of Hermann's tortoises.
- Compared reproductive success and survival rates of island females to a neighboring mainland population.
Main Results
- Sexually coercive males significantly outnumbered females, inflicting injuries and increasing mortality risk.
- Harassed females exhibited emaciation, reduced reproductive frequency, smaller clutches, and lower survival rates.
- The island population is undergoing an extinction event, with the last female predicted to die in 2083.
Conclusions
- High population density combined with a skewed adult sex ratio in a coercive mating system can lead to population collapse.
- This study provides the first empirical evidence of an extinction vortex driven by mating system dynamics in the wild.
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