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The timing of life events (phenology) can be influenced by climate. Studies from around the world tell us that climate cues and species' responses can vary greatly. If variation in climate effects on phenology is strong within a single ecosystem, climate change could lead to ecological disruption, but detailed data from diverse taxa within a single ecosystem are rare. We collated first sighting and median activity within a high-elevation environment for plants, insects, birds, mammals and an amphibian across 45 years (1975–2020). We related 10 812 phenological events to climate data to determine the relative importance of climate effects on species’ phenologies. We demonstrate significant variation in climate-phenology linkage across taxa in a single ecosystem. Both current and prior climate predicted changes in phenology. Taxa responded to some cues similarly, such as snowmelt date and spring temperatures; other cues affected phenology differently. For example, prior summer precipitation had no effect on most plants, delayed first activity of some insects, but advanced activity of the amphibian, some mammals, and birds. Comparing phenological responses of taxa at a single location, we find that important cues often differ among taxa, suggesting that changes to climate may disrupt synchrony of timing among taxa. 

The slow–fast continuum is a commonly used framework to describe variation in life-history strategies across species. Individual life histories have also been assumed to follow a similar pattern, especially in the pace-of-life syndrome literature. However, whether a slow–fast continuum commonly explains life-history variation among individuals within a population remains unclear. Here, we formally tested for the presence of a slow–fast continuum of life histories both within populations and across species using detailed long-term individual-based demographic data for 17 bird and mammal species with markedly different life histories. We estimated adult lifespan, age at first reproduction, annual breeding frequency, and annual fecundity, and identified the main axes of life-history variation using principal component analyses. Across species, we retrieved the slow–fast continuum as the main axis of life-history variation. However, within populations, the patterns of individual life-history variation did not align with a slow–fast continuum in any species. Thus, a continuum ranking individuals from slow to fast living is unlikely to shape individual differences in life histories within populations. Rather, individual life-history variation is likely idiosyncratic across species, potentially because of processes such as stochasticity, density dependence, and individual differences in resource acquisition that affect species differently and generate non-generalizable patterns across species. 

Abstract The increase of structural growth rates to compensate for a poor initial body condition, defined as compensatory growth, may have physiological costs, but little is known about its effects on individual fitness in the wild. Yellow-bellied marmots (Marmota flaviventer) are obligate hibernators and depend on fat accumulation acquired during an approximately 4-month summer to survive overwinter. We investigated the costs of survival and longevity of rapid growth in a wild population of yellow-bellied marmots. We used trapping data collected from 2002 to 2014 to calculate individual relative seasonal growth and assess its effects on longevity and annual survival of juveniles, yearlings, and adults. Sites were distributed in two main areas, down-valley and up-valley; the latter has a higher elevation and is an overall harsher environment. We found that relative seasonal growth had no effect on individual longevity or on juvenile and adult annual survival. For yearlings, the effect of relative seasonal growth on survival depended on the location: yearlings with high relative seasonal growth had lower survival if located up-valley, and higher survival if located down-valley. In conclusion, juveniles and adults do not appear to have detectable costs of rapid growth, although there are costs to yearling survival depending on environmental conditions. Substantial structural growth occurs when marmots are yearlings and our results are likely driven by the high conflicting demands of somatic growth versus maintenance at this stage. Thus, the costs of rapid growth are age and site dependent and may be seen in the short term for species facing temporal constraints on growth. 

Abstract Natural populations are exposed to seasonal variation in environmental factors that simultaneously affect several demographic rates (survival, development and reproduction). The resulting covariation in these rates determines population dynamics, but accounting for its numerous biotic and abiotic drivers is a significant challenge. Here, we use a factor‐analytic approach to capture partially unobserved drivers of seasonal population dynamics. We use 40 years of individual‐based demography from yellow‐bellied marmots (Marmota flaviventer) to fit and project population models that account for seasonal demographic covariation using a latent variable. We show that this latent variable, by producing positive covariation among winter demographic rates, depicts a measure of environmental quality. Simultaneously, negative responses of winter survival and reproductive‐status change to declining environmental quality result in a higher risk of population quasi‐extinction, regardless of summer demography where recruitment takes place. We demonstrate how complex environmental processes can be summarized to understand population persistence in seasonal environments.