Stochastic Variation in Avian Survival Rates: Life-History Predictions, Population Consequences, and the Potential Responses to Human Perturbations and Climate Change

Schmutz, Joel A.

doi:10.1007/978-0-387-78151-8_19

Cited by 13 publications

(21 citation statements)

References 73 publications

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“…Contrary to this theory, we found that although postfledging survival rates exhibited high sensitivity and elasticity values; they also exhibited high process variation and thus contributed the most to past changes in λ. The overall mean estimate of λ was ~ 1.0; indicating population stability during our study period and that departure from the demographic buffering life history strategy is not due to a case of maladaptation to the contemporary environment (Schmutz 2009). Rather, sage-grouse may exhibit a life history that is intermediate on the slow-fast continuum, where female survival is important and lability in related traits allows them to exploit opportune environments (Koons et al 2009), and survive at rates that, on average, are higher than most other galliformes, (Johnsgard 1983, Madge andMcGowan 2002), but are also sensitive to poor environmental conditions.…”

Section: Discussionmentioning

confidence: 74%

“…Alternatively, a species may exhibit demographic lability to fluctuating environmental conditions if the benefits of booms in demographic performance outweigh the busts (Koons et al 2009). Long-lived animals tend to exhibit demographic buffering (Gaillard et al 2000, Gaillard and Yoccoz 2003, Schmutz 2009), but little is known about species such as sagegrouse, which may be intermediate on the slowfast life history continuum (Koons et al 2014). As such, it is difficult to make predictions based on theory as to which vital rates should most influence sage-grouse population dynamics.…”

Section: Introductionmentioning

confidence: 99%

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Evaluating vital rate contributions to greater sage‐grouse population dynamics to inform conservation

et al. 2016

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Abstract. Species conservation efforts often use short-term studies that fail to identify the vital rates that contribute most to population growth. Although the greater sage-grouse (Centrocercus urophasianus; sage-grouse) is a candidate for protection under the U.S. Endangered Species Act, and is sometimes referred to as an umbrella species in the sagebrush (Artemisia spp.) biome of western North America, the failure of proposed management strategies to focus on key vital rates that may contribute most to achieving population stability remains problematic for sustainable conservation. To address this dilemma, we performed both prospective and retrospective perturbation analyses of a life cycle model based on a 12-yr study that encompassed nearly all sage-grouse vital rates. To validate our population models, we compared estimates of annual finite population growth rates (λ) from our female-based life cycle models to those attained from male-based lek counts. Post-fledging (i.e., after second year, second year, and juvenile) female survival parameters contributed most to past variation in λ during our study and had the greatest potential to change λ in the future, indicating these vital rates as important determinants of sage-grouse population dynamics. In addition, annual estimates of λ from female-based life cycle models and malebased lek data were similar, providing the most rigorous evidence to date that lek counts of males can serve as a valid index of sage-grouse population change. Our comparison of fixed and mixed statistical models for evaluating temporal variation in nest survival and initiation suggest that conservation planners use caution when evaluating short-term nesting studies and using associated fixed-effect results to develop conservation objectives. In addition, our findings indicated that greater attention should be paid to those factors affecting sage-grouse post-fledging females. Our approach demonstrates the need for more long-term studies of species vital rates across the life cycle. Such studies should address the decoupling of sampling variation from underlying process (co)variation in vital rates, identification of how such variation drives population dynamics, and how decision makers can use this information to re-direct conservation efforts to address the most limiting points in the life cycle for a given population.

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Section: Discussionmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Evaluating vital rate contributions to greater sage‐grouse population dynamics to inform conservation

et al. 2016

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“…The restructuring of zooplankton communities associated with changes in the North Atlantic current system (Hurrel 2000) may therefore directly affect little auk food availability, and this could have an effect on adult survival. Even a small change in adult survival will have a large effect on the population size of long-lived species (Doherty et al 2004), and a high variability in survival rates is also expected to decrease long-term population growth rates (Schmutz 2009). …”

Section: Resultsmentioning

confidence: 99%

Adverse foraging conditions may impact body mass and survival of a high Arctic seabird

et al. 2011

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Tradeoffs between current reproduction and future survival are widely recognized, but may only occur when food is limited: when foraging conditions are favorable, parents may be able to reproduce without compromising their own survival. We investigated these tradeoffs in the little auk (Alle alle), a small seabird with a single-egg clutch. During 2005-2007, we examined the relationship between body mass and survival of birds breeding under contrasting foraging conditions at two Arctic colonies. We used corticosterone levels of breeding adults as a physiological indicator of the foraging conditions they encountered during each reproductive season. We found that when foraging conditions were relatively poor (as reflected in elevated levels of corticosterone), parents ended the reproductive season with low body mass and suffered increased post-breeding mortality. A positive relationship between body mass and post-breeding survival was found in one study year; light birds incurred higher survival costs than heavy birds. The results of this study suggest that reproducing under poor foraging conditions may affect the post-breeding survival of long-lived little auks. They also have important demographic implications because even a small change in adult survival may have a large effect on populations of long-lived species.

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“…Variation in survival is unknown due to sparse data. Variability in survival and reproductive rates is important to consider because heightened variation tends to depress population growth rates (Schmutz, 2009). Thus, with respect to variability in real vital rates, this deterministic modeling effort may slightly overestimate population viability of yellowbilled loons.…”

Section: Simulated Harvest Scenariosmentioning

confidence: 99%

Stochastic Variation in Avian Survival Rates: Life-History Predictions, Population Consequences, and the Potential Responses to Human Perturbations and Climate Change

Cited by 13 publications

References 73 publications

Evaluating vital rate contributions to greater sage‐grouse population dynamics to inform conservation

Evaluating vital rate contributions to greater sage‐grouse population dynamics to inform conservation

Adverse foraging conditions may impact body mass and survival of a high Arctic seabird

Model-Based Predictions of the Effects of Harvest Mortality on Population Size and Trend of Yellow-Billed Loons

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