Modelling effects of nonbreeders on population growth estimates

Lee, Aline Magdalena; Reid, Jane M.; Beissinger, Steven R.

doi:10.1111/1365-2656.12592

Cited by 38 publications

(57 citation statements)

References 66 publications

(113 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, our results bring empirical support to the growing body of theoretical studies suggesting that failure to account for the influence of non-breeders (e.g. floaters) on estimates of stochastic population dynamics may lead to incorrect projections of population growth and extinction risk [11,19,49].…”

Section: Discussionsupporting

confidence: 65%

“…Recent studies suggest that non-breeders, such as floaters, are most probably to buffer sudden breeder losses when environmental changes cause reductions in the number of breeders but do not simultaneously influence floater fates in a significant way [11,12,49]. However, a number of key questions remain unsolved: how large should the pool of floaters be to cope with the detrimental impacts of stochasticity?…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Floaters may buffer the extinction risk of small populations: an empirical assessment

Robles

Ciudad

2017

Proc. R. Soc. B.

View full text Add to dashboard Cite

The high extinction risk of small populations is commonly explained by reductions in fecundity and breeder survival associated with demographic and environmental stochasticity. However, ecological theory suggests that population extinctions may also arise from reductions in the number of floaters able to replace the lost breeders. This can be particularly plausible under harsh fragmentation scenarios, where species must survive as small populations subjected to severe effects of stochasticity. Using a woodpecker study in fragmented habitats (2004 -2016), we provide here empirical support for the largely neglected hypothesis that floaters buffer population extirpation risks. After controlling for population size, patch size and the intrinsic quality of habitat, populations in patches with floaters had a lower extinction probability than populations in patches without floaters (0.013 versus 0.131). Floaters, which often replace the lost breeders, were less likely to occur in small and low-quality patches, showing that population extirpations may arise from unnoticed reductions in floater numbers in poor-quality habitats. We argue that adequate pools of the typically overlooked floaters may buffer extirpation risks by reducing the detrimental impacts of demographic and environmental stochasticity. However, unravelling the influence of floaters in buffering stochastic effects and promoting population stability require additional studies in an ample array of species and stochastic scenarios.

show abstract

Section: Discussionsupporting

confidence: 65%

Section: Discussionmentioning

confidence: 99%

Floaters may buffer the extinction risk of small populations: an empirical assessment

Robles

Ciudad

2017

Proc. R. Soc. B.

View full text Add to dashboard Cite

show abstract

“…only breeders), introduces much more serious biases than those examined here (Lee et al . ). Models that classify individuals by reproductive success therefore have an important role in analysing the dynamics of certain types of populations.…”

Section: Discussionmentioning

confidence: 97%

“…It has previously been shown that the deterministic population growth rate tends to be less sensitive to changes in breeding probabilities than to changes in survival, particularly in long‐lived species (Lee et al . ). Then we would also expect fluctuations in breeding probabilities to have less effect on population growth and extinction, thus weakening the selection pressures that may lead to demographic buffering (Pfister ; Gaillard et al .…”

Section: Discussionmentioning

confidence: 97%

Modelling time to population extinction when individual reproduction is autocorrelated

et al. 2017

View full text Add to dashboard Cite

In nature, individual reproductive success is seldom independent from year to year, due to factors such as reproductive costs and individual heterogeneity. However, population projection models that incorporate temporal autocorrelations in individual reproduction can be difficult to parameterise, particularly when data are sparse. We therefore examine whether such models are necessary to avoid biased estimates of stochastic population growth and extinction risk, by comparing output from a matrix population model that incorporates reproductive autocorrelations to output from a standard age-structured matrix model that does not. We use a range of parameterisations, including a case study using moose data, treating probabilities of switching reproductive class as either fixed or fluctuating. Expected time to extinction from the two models is found to differ by only small amounts (under 10%) for most parameterisations, indicating that explicitly accounting for individual reproductive autocorrelations is in most cases not necessary to avoid bias in extinction estimates.

show abstract

“…Assessing the effects of different demographic rates on populations requires that rates are estimated appropriately: for fecundity, non‐breeders and non‐breeding episodes must be taken into account (Lee, Reid, & Beissinger, ). Here, we found that relatively small differences in colony fecundity rate are associated with very different colony pup production trajectories.…”

Section: Discussionmentioning

confidence: 99%

Environment‐sensitive mass changes influence breeding frequency in a capital breeding marine top predator

Smout

King

Pomeroy

2019

Journal of Animal Ecology

View full text Add to dashboard Cite

The trade‐off between survival and reproduction in resource‐limited iteroparous animals can result in some individuals missing some breeding opportunities. In practice, even with the best observation regimes, deciding whether ‘missed’ years represent real pauses in breeding or failures to detect breeding can be difficult, posing problems for the estimation of individual reproductive output and overall population fecundity. We corrected fecundity estimates by determining whether breeding had occurred in skipped years, using long‐term capture–recapture observation datasets with parallel longitudinal mass measurements, based on informative underlying relationships between individuals’ mass, breeding status and environmental drivers in a capital breeding phocid, the grey seal. Bayesian modelling considered interacting processes jointly: temporal changes in a phenotypic covariate (mass); relationship of mass to breeding probability; effects of maternal breeding state and mark type on resighting. Full reproductive histories were imputed, with the status of unobserved animals estimated as breeding or non‐breeding, accounting for local environmental variation. Overall fecundity was then derived for Scottish breeding colonies with contrasting pup production trends. Maternal mass affected breeding likelihood. Mothers with low body mass at the end of breeding were less likely to bear a pup the following year. Successive breeding episodes incurred a cost in reduced body mass which was more pronounced for North Rona, Outer Hebrides (NR) mothers. Skipping breeding increased subsequent pupping probability substantially for low mass females. Poor environmental conditions were associated with declines in breeding probability at both colonies. Seal mass gain between breeding seasons was (a) negatively associated with lagged North Atlantic Oscillation for seals at NR and (b) positively associated with an index of seal prey (Ammodytes spp) abundance at Isle of May, Firth of Forth (IM). Overall fecundity was marginally greater at IM (increasing/stable pup production) than at NR (decreasing). No effects of mass were detected on maternal survival. Skipping breeding in female grey seals appears to be an individual mass‐dependent constraint moderated by previous reproductive output and local environmental conditions. Different demographic trends at breeding colonies were consistent with the fecundities estimated using this method, which is general and adaptable to other situations.

show abstract

Modelling effects of nonbreeders on population growth estimates

Cited by 38 publications

References 66 publications

Floaters may buffer the extinction risk of small populations: an empirical assessment

Floaters may buffer the extinction risk of small populations: an empirical assessment

Modelling time to population extinction when individual reproduction is autocorrelated

Environment‐sensitive mass changes influence breeding frequency in a capital breeding marine top predator

Contact Info

Product

Resources

About