Demographic Analysis from Summaries of an Age‐Structured Population

Link, William A.; Royle, J. Andrew; Hatfield, Jeff S.

doi:10.1111/j.0006-341x.2003.00091.x

Cited by 38 publications

(28 citation statements)

References 12 publications

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“…Although it is theoretically possible to obtain parameter estimates with only one survey replicate per time period, our simulations suggest that these values could be imprecise even for relatively large sampling efforts. As such, we caution against the use of a single sampling event unless prior information on detection probabilities is available (Link et al 2003). We presented the median parameter values of 100 simulated data sets for several levels of data collection intensity.…”

Section: Discussionmentioning

confidence: 99%

Modeling structured population dynamics using data from unmarked individuals

Zipkin¹,

Thorson

See³

et al. 2014

Ecology

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133

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Abstract. The study of population dynamics requires unbiased, precise estimates of abundance and vital rates that account for the demographic structure inherent in all wildlife and plant populations. Traditionally, these estimates have only been available through approaches that rely on intensive mark-recapture data. We extended recently developed Nmixture models to demonstrate how demographic parameters and abundance can be estimated for structured populations using only stage-structured count data. Our modeling framework can be used to make reliable inferences on abundance as well as recruitment, immigration, stage-specific survival, and detection rates during sampling. We present a range of simulations to illustrate the data requirements, including the number of years and locations necessary for accurate and precise parameter estimates. We apply our modeling framework to a population of northern dusky salamanders (Desmognathus fuscus) in the mid-Atlantic region (USA) and find that the population is unexpectedly declining. Our approach represents a valuable advance in the estimation of population dynamics using multistate data from unmarked individuals and should additionally be useful in the development of integrated models that combine data from intensive (e.g., mark-recapture) and extensive (e.g., counts) data sources.

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Section: Discussionmentioning

confidence: 99%

Modeling structured population dynamics using data from unmarked individuals

Zipkin¹,

Thorson

See³

et al. 2014

Ecology

Self Cite

133

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“…Through May of 2008, there were relatively few breeders in the population, but with continued data collection, closer analysis of breeding state transitions may reveal important patterns. First, it may be that breeding behavior is a more important indicator of population success than survival, as survival in the EMP has been fairly good to date (based on comparisons with survival in the AWBP; Link et al 2003) while breeding has not been very successful (only 1 individual fledged from 24 nests through May of 2008); thus reproduction appears to be the limiting factor in establishment of the EMP. In addition, given that our measure of genotype quality was dam productivity, there is a stronger argument for an expectation of correlation between a dam's productivity in captivity and her offspring's productivity in the wild (an analysis that will be possible in the near future), rather than with her offspring's survival in the wild.…”

Section: S570mentioning

confidence: 99%

Bayesian analysis of multi-state data with individual covariates for estimating genetic effects on demography

2011

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Inbreeding depression is frequently a concern of managers interested in restoring endangered species. Decisions to reduce the potential for inbreeding depression by balancing genotypic contributions to reintroduced populations may exact a cost on long-term demographic performance of the population if those decisions result in reduced numbers of animals released and/or restriction of particularly successful genotypes (i.e., heritable traits of particular family lines). As part of an effort to restore a migratory flock of Whooping Cranes (Grus americana) to eastern North America using the offspring of captive breeders, we obtained a unique dataset which includes post-release mark-recapture data, as well as the pedigree of each released individual. We developed a Bayesian formulation of a multi-state model to analyze radio-telemetry, band-resight, and dead recovery data on reintroduced individuals, in order to track survival and breeding state transitions. We used studbook-based individual covariates to examine the comparative evidence for and degree of effects of inbreeding, genotype, and genotype quality on post-release survival of reintroduced individuals. We demonstrate implementation of the Bayesian multi-state model, which allows for the integration of imperfect detection, multiple data types, random effects, and individual-and time-dependent covariates. Our results provide only weak evidence for an effect of the quality of an individual's genotype in captivity on post-release survival as well as for an effect of inbreeding on post-release survival. We plan to integrate our results into a decisionanalytic modeling framework that can explicitly examine tradeoffs between the effects of inbreeding and the effects of genotype and demographic stochasticity on population establishment.

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“…Thus, estimated rates for that population (Link et al 2003) were applied to simulated WF birds. We applied the estimated overall survival rate from their work (0.91; model CAAE) to all age and breeding classes of WF birds in place of survival rates estimated from CR females (0.66-0.82 for unpaired birds, 0.79-0.94 for birds in breeding classes).…”

Section: Alternatives To the Baseline Modelmentioning

confidence: 99%

“…We applied the estimated overall survival rate from their work (0.91; model CAAE) to all age and breeding classes of WF birds in place of survival rates estimated from CR females (0.66-0.82 for unpaired birds, 0.79-0.94 for birds in breeding classes). Link et al (2003) also provided information on year-to-year variability in survival rate as well as estimation uncertainty; therefore, the survival rate applied to WF birds varied from year to year and among simulation runs (to account for estimation uncertainty). For productivity, we assumed that CR and WF birds shared a common rate of transition into the breeder classes (i.e., probability that an unpaired female forms her first pair bond).…”

Section: Alternatives To the Baseline Modelmentioning

confidence: 99%

“…However, we applied the ARWB estimate of average perbreeder productivity rate (0.33; 1938-2001 period) to WF birds in place of the three breeding class-specific productivity rates estimated from the CR data (0.05, 0.0, and 0.36 for classes P, N, and F, respectively). As we did for the survival rate parameter, we incorporated the annual stochastic variation and parameter estimation uncertainty (provided by Link et al 2003) in our simulations of recruitment rate; thus recruitment rate for WF birds varied among years and simulation runs.…”

Section: Alternatives To the Baseline Modelmentioning

confidence: 99%

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Evaluating release alternatives for a long-lived bird species under uncertainty about long-term demographic rates

Moore

Converse²,

Folk

et al. 2010

J Ornithol

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The release of animals to reestablish an extirpated population is a decision problem that is often attended by considerable uncertainty about the probability of success. Annual releases of captive-reared juvenile Whooping Cranes (Grus americana) were begun in 1993 in central Florida, USA, to establish a breeding, non-migratory population. Over a 12-year period, 286 birds were released, but by 2004, the introduced flock had produced only four wildfledged birds. Consequently, releases were halted over managers' concerns about the performance of the released flock and uncertainty about the efficacy of further releases. We used data on marked, released birds to develop predictive models for addressing whether releases should be resumed, and if so, under what schedule. To examine the outcome of different release scenarios, we simulated the survival and productivity of individual female birds under a baseline model that recognized age and breeding-class structure and which incorporated empirically estimated stochastic elements. As data on wild-fledged birds from captive-reared parents were sparse, a key uncertainty that confronts release decision-making is whether captive-reared birds and their offspring share the same vital rates. Therefore, we used data on the only population of wild Whooping Cranes in existence to construct two alternatives to the baseline model. The probability of population persistence was highly sensitive to the choice of these three models. Under the baseline model, extirpation of the population was nearly certain under any scenario of resumed releases. In contrast, the model based on estimates from wild birds projected a high probability of persistence under any release scenario, including cessation of releases. Therefore, belief in either of these models suggests that further releases are an ineffective use of resources. In the third model, which simulated a population Allee effect, population persistence was sensitive to the release decision: high persistence probability was achieved only through the release of more birds, whereas extirpation was highly probable with cessation of releases. Despite substantial investment of time and effort in the release program, evidence collected to date does not favor one model over another; therefore, any decision about further releases must be made under considerable biological uncertainty. However, given an assignment of credibility weight to each model, a best, informed decision about releases can be made under uncertainty. Furthermore, if managers can periodically revisit the release decision and collect monitoring data to further inform the models, then managers have a basis for confronting uncertainty and adaptively managing releases through time.

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Demographic Analysis from Summaries of an Age‐Structured Population

Cited by 38 publications

References 12 publications

Modeling structured population dynamics using data from unmarked individuals

Modeling structured population dynamics using data from unmarked individuals

Bayesian analysis of multi-state data with individual covariates for estimating genetic effects on demography

Evaluating release alternatives for a long-lived bird species under uncertainty about long-term demographic rates

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