Survival Trends in Southern Elephant Seals
Author Information
Author(s): Siobhan C. de Little, Corey J. A. Bradshaw, Clive R. McMahon, Mark A. Hindell
Primary Institution: Charles Darwin University
Hypothesis
Intrinsic factors regulate growth only near carrying capacity, while extrinsic factors are the predominant drivers of change when populations are below carrying capacity.
Conclusion
Both environmental conditions and population density interact to affect juvenile survival in southern elephant seals.
Supporting Evidence
- First-year survival decreased with density during the period of highest population size.
- Survival increased during years with positive Southern Oscillation Index anomalies.
- Environmental conditions during the mother's foraging trip significantly influenced first-year survival.
Takeaway
This study looks at how the environment and the number of seals affect how many baby seals survive their first year.
Methodology
Age-structured mark-recapture models were used to estimate age-specific probabilities of survival over five decades.
Potential Biases
Potential over-dispersion in survival estimates due to non-compliance with CJS model assumptions.
Limitations
The study may not fully capture the effects of density regulation due to high environmental variability.
Participant Demographics
Southern elephant seals at Macquarie Island, with data spanning from 1951 to 1999.
Statistical Information
P-Value
p<0.0001
Statistical Significance
p<0.0001
Digital Object Identifier (DOI)
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