Tests of the Assumptions Underlying Life Table Methods for Estimating Parameters from Cohort Data

Anderson, David R.; Wywialowski, Alice P.; Burnham, Kenneth P.

doi:10.2307/1937009

Cited by 34 publications

(14 citation statements)

References 11 publications

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“…For example, several avian ecologists (Anderson et al ., 1981;Lakhani & Newton, 1983) noted that one of the main models used to estimate age-specific survival rates from recovery data of birds ringed as young is '... misleading, untrustworthy and gives a false sense of precision' (Anderson et al ., 1985, p. 97). These ecologists believe that the use of this model may account for the conclusions forwarded by earlier researchers that avian mortality is age independent (Botkin & Miller, 1974).…”

Section: Introductionmentioning

confidence: 99%

Age structure changes and extraordinary lifespan in wild medfly populations

et al. 2008

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SummaryThe main purpose of this study was to test the hypotheses that major changes in age structure occur in wild populations of the Mediterranean fruit fly (medfly) and that a substantial fraction of individuals survive to middle age and beyond (> 3-4 weeks). We thus brought reference life tables and deconvolution models to bear on medfly mortality data gathered from a 3-year study of field-captured individuals that were monitored in the laboratory. The average timeto-death of captured females differed between sampling dates by 23.9, 22.7, and 37.0 days in the 2003, 2004, and 2005 field seasons, respectively. These shifts in average times-to-death provided evidence of changes in population age structure. Estimates indicated that middle-aged medflies (> 30 days) were common in the population. A surprise in the study was the extraordinary longevity observed in field-captured medflies. For example, 19 captured females but no reference females survived in the laboratory for 140 days or more, and 6 captured but no reference males survived in the laboratory for 170 days or more. This paper advances the study of aging in the wild by introducing a new method for estimating age structure in insect populations, demonstrating that major changes in age structure occur in field populations of insects, showing that middle-aged individuals are common in the wild, and revealing the extraordinary lifespans of wild-caught individuals due to their early life experience in the field.

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Section: Introductionmentioning

confidence: 99%

Age structure changes and extraordinary lifespan in wild medfly populations

et al. 2008

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“…Age-ratio analysis has fallen in and out of vogue in ecology (Hanson 1963, Caughley 1974, Anderson et al 1981, Skalski et al 2005) and recent applications have rekindled debate over the validity of demographic estimates derived from this approach because critical assumptions may be violated (Conn et al 2005, Ricklefs andRohwer 2005). Age ratios are often used as an index of reproduction in monitoring and management programs (Megrey 1989, McCullough et al 1994 Wanner et al 2004, Iverson et al 2004, Skalski et al 2005.…”

Section: Introductionmentioning

confidence: 99%

Reconstructing the Historic Demography of an Endangered Seabird

Beissinger

Peery

2007

Ecology

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Abstract. Reducing extinction risk for threatened species requires determining which demographic parameters are depressed and causing population declines. Museum collections may constitute a unique, underutilized resource for measuring demographic changes over long time periods using age-ratio analysis. We reconstruct the historic demography of a U.S. federally endangered seabird, the Marbled Murrelet (Brachyramphus marmoratus), from specimens collected ;100 years ago for comparison with predictions from comparative analyses and with results from contemporary field studies using both age-ratio analysis and conventional demographic estimators. Reproduction in the late 1800s and early 1900s matched predictions from comparative analysis, but was 8-9 times greater than contemporary estimates, whereas adult survival was unchanged. Historic reproductive rates would support stable populations, but contemporary levels should result in population declines. Contemporary demographic estimates derived from age-ratio analysis were similar to estimates from conventional estimators. Using museum specimens to reconstruct historic demography provides a unique approach to identify causes of decline and to set demographic benchmarks for recovery of endangered species that meet most assumptions of age-ratio analysis.

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“…For pinnipeds, estimates of life‐history parameters can be obtained from cross‐sectional samples from animals collected for research, during subsistence harvests, or incidental to fisheries (Lander , Pitcher and Calkins , Boyd , York , Bester , Hammill and Gosselin , Lima and Páez ) but these data are often biased toward specific sex or age classes and can lead to misleading inferences (Anderson et al . , Messier , Menkens and Boyce ). Mark‐recapture studies of uniquely marked pinnipeds offer an alternative and often less biased method of estimating life‐history parameters and have become a more common method to estimate vital rates ( e.g ., Testa , Huber et al .…”

mentioning

confidence: 97%

Age‐ and sex‐specific survival of California sea lions (Zalophus californianus) at San Miguel Island, California

DeLong

Melin

Laake

et al. 2017

Marine Mammal Science

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We conducted a mark‐recapture study of California sea lions (Zalophus californianus) using pups branded on San Miguel Island, California, from 1987 to 2014, and annual resightings from 1990 to 2015. We used the Burnham model (Burnham 1993), an extension of the Cormack‐Jolly‐Seber mark‐recapture model, which includes recoveries of dead animals, to analyze age, sex, and annual patterns in survival. Generally, females had higher survival than males. For female pups, the average annual survival was 0.600 and for male pups it was 0.574. Yearling survival was 0.758 and 0.757 for females and males, respectively. Peak annual survival was at age 5 and was 0.952 for females and 0.931 for males. Pups with larger mass at branding had higher survival as pups and yearlings, but the effect was relative within each cohort because of large between‐cohort variability in survival. Annual variability in sea surface temperature (SST) affected survival. For each 1°C increase in SST, the odds of survival decreased by nearly 50% for pups and yearlings; negative SST anomalies yielded higher survival. Annual variation in male survival was partly explained by leptospirosis outbreaks. Our study provides a unique view of one demographic parameter that contributed to the successful recovery of the California sea lion population.

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Tests of the Assumptions Underlying Life Table Methods for Estimating Parameters from Cohort Data

Cited by 34 publications

References 11 publications

Age structure changes and extraordinary lifespan in wild medfly populations

Age structure changes and extraordinary lifespan in wild medfly populations

Reconstructing the Historic Demography of an Endangered Seabird

Age‐ and sex‐specific survival of California sea lions (Zalophus californianus) at San Miguel Island, California

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