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Seasonal environmental conditions shape the behavior and life history of virtually all organisms. Climate change is modifying these seasonal environmental conditions, which threatens to disrupt population dynamics. It is conceivable that climatic changes may be beneficial in one season but result in detrimental conditions in another because life-history strategies vary between these time periods. We analyzed the temporal trends in seasonal survival of yellow-bellied marmots (Marmota flaviventer) and explored the environmental drivers using a 40-y dataset from the Colorado Rocky Mountains (USA). Trends in survival revealed divergent seasonal patterns, which were similar across age-classes. Marmot survival declined during winter but generally increased during summer. Interestingly, different environmental factors appeared to drive survival trends across age-classes. Winter survival was largely driven by conditions during the preceding summer and the effect of continued climate change was likely to be mainly negative, whereas the likely outcome of continued climate change on summer survival was generally positive. This study illustrates that seasonal demographic responses need disentangling to accurately forecast the impacts of climate change on animal population dynamics.

It has recently been recognised that populations are rarely in demographic equilibrium, but rather in a 'transient' state. To examine how transient dynamics influence our empirical understanding of the links between changes in demographic rates and population growth, we conducted a 32‐year study of Columbian ground squirrels. The population increased rapidly for 10 years, followed by a 2‐year crash, and a gradual 19‐year recovery. Transient life table response experiment (LTRE) analysis showed that demographic stochasticity accounted for approximately one‐fourth of the variation in population growth, leaving the majority to be explained by environmental influences. These relatively small rodents appeared to have a slow pace of life. But unlike the general pattern for large mammals with slow life histories, ground squirrel survival did not exhibit low variation associated with environmental 'buffering'; instead, survival varied substantially over time and contributed substantially (78%) to changes in abundance over the long‐term study, with minor contributions from reproduction and unstable stage structure. [ABSTRACT FROM AUTHOR]

Estimates of demographic parameters based on capture-mark-recapture (CMR) methods may be biased when some individuals in the population are temporarily unavailable for capture (temporary emigration). We estimated snowshoe hare abundance, apparent survival, and probability of temporary emigration in a population of snowshoe hares (Lepus americanus Erxleben, 1777) in the Yukon (Canada) using Pollock's robust design CMR model, and population density using spatially explicit CMR models. Survival rates strongly varied among cyclic phases, seasons, and across five population cycles. We found strong evidence that temporary emigration was Markovian (i.e., nonrandom), suggesting that it varied among individuals that were temporary emigrant in the previous sampling period and those that were present in the sampled area. The probability of temporary emigration for individuals that were in the study area during the previous sampling occasion ([gamma]') varied among cycles. Probability that individuals that were temporarily absent from the sampled area would remain temporary emigrants ([gamma]') showed strongly seasonal pattern, low in winter and high during summers. Snowshoe hare population density ranged from 0.017 (0.015-0.05) hares/ha to 4.43 (3.90-5.00) hares/ha and showed large-scale cyclical fluctuations. Autocorrelation functions and autoregressive analyses revealed that our study population exhibited statistically significant cyclic fluctuations, with a periodicity of 9-10 years. Key words: autoregressive analysis, boreal ecosystem, capture-mark-recapture analysis, capture probability, Lepus americanus, density dependence, Pollock's robust design, snowshoe hare cycles, survival, spatial capture-recapture model, temporary emigration, wildlife's 10-year cycle. Les estimations de parametres demographiques reposant sur des methodes de capture-marquage-recapture (CMR) pourraient etre biaisees dans les situations ou certains individus de la population sont provisoirement non disponibles pour la capture (emigration temporaire). Nous avons estime l'abondance, le taux de survie apparent et la probabilite d'emigration temporaire au sein d'une population de lievres d'Amerique (Lepus americanus Erxleben, 1777) au Yukon (Canada) en utilisant le modele CMR a schema robuste de Pollock, et la densite de la population en utilisant des modeles CMR spatialement explicites. Les taux de survie variaient considerablement au fil des phases du cycle et des saisons et entre cinq cycles demographiques. Nous avons releve des indices solides du caractere markovien (c.-a-d., non aleatoire) de l'emigration temporaire, donnant a penser que cette derniere differe entre les individus qui etaient des emigrants temporaires durant la periode d'echantillonnage precedente et ceux qui etaient presents dans le secteur echantillonne. La probabilite d'emigration temporaire pour les individus qui etaient dans le secteur d'etude durant l'occasion d'echantillonnage precedent ([gamma]') variait entre les cycles. La probabilite que des individus qui etaient temporairement absents du secteur echantillonne demeurent des emigrants temporaires ([gamma]') presentait une forte saisonnalite, etant faible en hiver et elevee durant les etes. La densite de la population de lievres d'Amerique allait de 0,017 (0,015-0,05) lievres/ha a 4,43 (3,90-5,00) lievres/ha et presentait de vastes fluctuations cycliques. Des fonctions d'autocorrelation et des analyses autoregressives ont revele que la population etudiee presentait des fluctuations cycliques statistiquement significatives, d'une periodicite de 9-10 ans. [Traduit par la Redaction] Mots-cles : analyse autoregressive, ecosysteme boreal, analyse de capture-marquage-recapture, probabilite de capture, Lepus americanus, dependance sur la densite, schema robuste de Pollock, cycles des lievres d'Amerique, survie, modele spatial de capture-recapture, emigration temporaire, cycle demographique decennal., Introduction Studies of population dynamics often rely on individual-based data collected by following fates of individuals that are uniquely marked. When such data are available, capture-mark-recapture (CMR) methodologies offer a [...]