13 results on '"Cubaynes, Sarah"'
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2. Climate change does not decouple interactions between a central‐place‐foraging predator and its migratory prey.
- Author
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Gicquel, Morgane, East, Marion L., Hofer, Heribert, Cubaynes, Sarah, and Benhaiem, Sarah
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PREDATION ,CLIMATE change ,PREY availability ,SOCIAL status ,MIGRATORY animals - Abstract
Little is known about potential cascading effects of climate change on the ability of predators to exploit mobile aggregations of prey with a spatiotemporal distribution largely determined by climatic conditions. If predators employ central‐place foraging when rearing offspring, the ability of parents to locate sufficient prey could be reduced by climate change. In the Serengeti National Park, Tanzania, migratory species dominate mammalian herbivore biomass. These migratory herds exploit nutrient‐rich vegetation on the southern plains in the rainy season and surface water in the northwest in the dry season. Female spotted hyenas Crocuta crocuta breed throughout the year and use long‐distance central‐place‐foraging "commuting trips" to migratory herds to fuel lactation for ≥12 months. Changes in rainfall patterns that alter prey movements may decrease the ability of mothers to locate profitable foraging areas and thus increase their overall commuting effort, particularly for high‐ranking females that have priority of access to food resources within their clan territory and thus less commuting experience. In hyena clan territories, this may be reflected by a decrease in migratory herd presence and a decrease in the presence of lactating females, as maternal den presence represents the opposite of commuting effort. We investigated the strength of the relationship between rainfall volume, migratory herd presence in three hyena clan territories, and the responses of lactating females to this climate/prey relationship in terms of maternal den presence, using an observation‐based dataset spanning three decades. The probability of migratory herd presence in hyena clan territories increased with the amount of rainfall 2 months earlier, and maternal den presence increased with migratory herd presence. Rainfall volume substantially increased over 30 years, whereas the presence of migratory herds in hyena clans and the strength of the relationship between rainfall and migratory herd presence decreased. Hyenas thus adjusted well to the climate change‐induced decreased the presence of migratory herds in their territories, since maternal den presence did not decrease over 30 years and still matched periods of high prey abundance, irrespective of female social status. These results suggest a high plasticity in the response of this keystone predator to environmental variability. [ABSTRACT FROM AUTHOR] more...
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- 2022
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3. The kinship matrix: inferring the kinship structure of a population from its demography.
- Author
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Coste, Christophe F. D., Bienvenu, François, Ronget, Victor, Ramirez‐Loza, Juan‐Pablo, Cubaynes, Sarah, Pavard, Samuel, and Coulson, Tim
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KINSHIP ,DEMOGRAPHY ,POPULATION dynamics ,POPULATION forecasting - Abstract
The familial structure of a population and the relatedness of its individuals are determined by its demography. There is, however, no general method to infer kinship directly from the life cycle of a structured population. Yet, this question is central to fields such as ecology, evolution and conservation, especially in contexts where there is a strong interdependence between familial structure and population dynamics. Here, we give a general formula to compute, from any matrix population model, the expected number of arbitrary kin (sisters, nieces, cousins, etc) of a focal individual ego, structured by the class of ego and of its kin. Central to our approach are classic but little‐used tools known as genealogical matrices. Our method can be used to obtain both individual‐based and population‐wide metrics of kinship, as we illustrate. It also makes it possible to analyse the sensitivity of the kinship structure to the traits implemented in the model. [ABSTRACT FROM AUTHOR] more...
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- 2021
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4. Modeling the demography of species providing extended parental care: A capture–recapture multievent model with a case study on polar bears (Ursus maritimus).
- Author
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Cubaynes, Sarah, Aars, Jon, Yoccoz, Nigel G., Pradel, Roger, Wiig, Øystein, Ims, Rolf A., and Gimenez, Olivier
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POLAR bear , *DEMOGRAPHY , *BIOLOGICAL extinction , *ADULT children , *ANIMAL populations , *ANIMAL population density - Abstract
In species providing extended parental care, one or both parents care for altricial young over a period including more than one breeding season. We expect large parental investment and long‐term dependency within family units to cause high variability in life trajectories among individuals with complex consequences at the population level. So far, models for estimating demographic parameters in free‐ranging animal populations mostly ignore extended parental care, thereby limiting our understanding of its consequences on parents and offspring life histories.We designed a capture–recapture multievent model for studying the demography of species providing extended parental care. It handles statistical multiple‐year dependency among individual demographic parameters grouped within family units, variable litter size, and uncertainty on the timing at offspring independence. It allows for the evaluation of trade‐offs among demographic parameters, the influence of past reproductive history on the caring parent's survival status, breeding probability, and litter size probability, while accounting for imperfect detection of family units. We assess the model performance using simulated data and illustrate its use with a long‐term dataset collected on the Svalbard polar bears (Ursus maritimus).Our model performed well in terms of bias and mean square error and in estimating demographic parameters in all simulated scenarios, both when offspring departure probability from the family unit occurred at a constant rate or varied during the field season depending on the date of capture. For the polar bear case study, we provide estimates of adult and dependent offspring survival rates, breeding probability, and litter size probability. Results showed that the outcome of the previous reproduction influenced breeding probability.Overall, our results show the importance of accounting for i) the multiple‐year statistical dependency within family units, ii) uncertainty on the timing at offspring independence, and iii) past reproductive history of the caring parent. If ignored, estimates obtained for breeding probability, litter size, and survival can be biased. This is of interest in terms of conservation because species providing extended parental care are often long‐living mammals vulnerable or threatened with extinction. [ABSTRACT FROM AUTHOR] more...
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- 2021
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5. Mapping and explaining wolf recolonization in France using dynamic occupancy models and opportunistic data.
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Louvrier, Julie, Duchamp, Christophe, Lauret, Valentin, Marboutin, Eric, Cubaynes, Sarah, Choquet, Rémi, Miquel, Christian, and Gimenez, Olivier
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COLONIZATION (Ecology) ,HUMAN-animal relationships ,ECOLOGICAL mapping ,WOLVES ,CARNIVOROUS animals - Abstract
While large carnivores are recovering in Europe, assessing their distributions can help to predict and mitigate conflicts with human activities. Because they are highly mobile, elusive and live at very low density, modeling their distributions presents several challenges due to 1) their imperfect detectability, 2) their dynamic ranges over time and 3) their monitoring at large scales consisting mainly of opportunistic data without a formal measure of the sampling effort. Here, we focused on wolves
Canis lupus that have been recolonizing France since the early 1990s. We evaluated the sampling effort a posteriori as the number of observers present per year in a cell based on their location and professional activities. We then assessed wolf range dynamics from 1994 to 2016, while accounting for species imperfect detection and time‐ and space‐varying sampling effort using dynamic site‐occupancy models. Ignoring the effect of sampling effort on species detectability led to underestimating the number of occupied sites by more than 50% on average. Colonization appeared to be negatively influenced by the proportion of a site with an altitude higher than 2500 m and positively influenced by the number of observed occupied sites at short and long‐distances, forest cover, farmland cover and mean altitude. The expansion rate, defined as the number of occupied sites in a given year divided by the number of occupied sites in the previous year, decreased over the first years of the study, then remained stable from 2000 to 2016. Our work shows that opportunistic data can be analyzed with species distribution models that control for imperfect detection, pending a quantification of sampling effort. Our approach has the potential for being used by decision‐makers to target sites where large carnivores are likely to occur and mitigate conflicts. [ABSTRACT FROM AUTHOR] more...- Published
- 2018
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6. Modeling the impact of selective harvesting on red deer antlers.
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Pozo, Rocío A., Schindler, Susanne, Cubaynes, Sarah, Cusack, Jeremy J., Coulson, Tim, and Malo, Aurelio F.
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HUNTING ,RED deer ,ANTLERS ,OUTDOOR recreation ,RUM National Nature Reserve (Scotland) - Abstract
ABSTRACT Hunting is a common component in the management of ungulate species. Despite its widespread use, the influence of selective harvesting on phenotypic trait change is still ambiguous, and represents a critical gap in our understanding of the responses of wild populations under harvest. Using the long-term red deer ( Cervus elaphus) dataset (1972-2012) from the Isle of Rum National Nature Reserve, Scotland, we assessed the relationship between antler length and key demographic processes (i.e., survival, recruitment, antler growth, parent-offspring trait correlation) for the male component of the population. We then constructed the first integral projection model for this species to examine the effects of simulated trophy hunting on 2 population-level parameters: the stable antler size distribution and the relative reproductive value of males. When male mortality rates due to hunting were <20%, the effect on antler size distribution and the reproductive value function were relatively small. However, as mortality due to hunting increased to 50% in large individuals, the direct effects of hunting on mean antler size and reproductive value became evident. Our model acts as a useful starting point to investigate the ecological and evolutionary consequences of hunting in red deer. © 2016 The Wildlife Society. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
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7. Density-dependent intraspecific aggression regulates survival in northern Yellowstone wolves ( Canis lupus).
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Cubaynes, Sarah, MacNulty, Daniel R., Stahler, Daniel R., Quimby, Kira A., Smith, Douglas W., Coulson, Tim, and Boutin, Stan
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CANIS , *WOLVES , *PREDATION , *ANIMAL aggression - Abstract
Understanding the population dynamics of top-predators is essential to assess their impact on ecosystems and to guide their management. Key to this understanding is identifying the mechanisms regulating vital rates., Determining the influence of density on survival is necessary to understand the extent to which human-caused mortality is compensatory or additive. In wolves ( Canis lupus), empirical evidence for density-dependent survival is lacking. Dispersal is considered the principal way in which wolves adjust their numbers to prey supply or compensate for human exploitation. However, studies to date have primarily focused on exploited wolf populations, in which density-dependent mechanisms are likely weak due to artificially low wolf densities., Using 13 years of data on 280 collared wolves in Yellowstone National Park, we assessed the effect of wolf density, prey abundance and population structure, as well as winter severity, on age-specific survival in two areas (prey-rich vs. prey-poor) of the national park. We further analysed cause-specific mortality and explored the factors driving intraspecific aggression in the prey-rich northern area of the park., Overall, survival rates decreased during the study. In northern Yellowstone, density dependence regulated adult survival through an increase in intraspecific aggression, independent of prey availability. In the interior of the park, adult survival was less variable and density-independent, despite reduced prey availability. There was no effect of prey population structure in northern Yellowstone, or of winter severity in either area. Survival was similar among yearlings and adults, but lower for adults older than 6 years., Our results indicate that density-dependent intraspecific aggression is a major driver of adult wolf survival in northern Yellowstone, suggesting intrinsic density-dependent mechanisms have the potential to regulate wolf populations at high ungulate densities. When low prey availability or high removal rates maintain wolves at lower densities, limited inter-pack interactions may prevent density-dependent survival, consistent with our findings in the interior of the park. [ABSTRACT FROM AUTHOR] more...
- Published
- 2014
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8. Strategies for fitting nonlinear ecological models in R, AD Model Builder, and BUGS.
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Bolker, Benjamin M., Gardner, Beth, Maunder, Mark, Berg, Casper W., Brooks, Mollie, Comita, Liza, Crone, Elizabeth, Cubaynes, Sarah, Davies, Trevor, Valpine, Perry, Ford, Jessica, Gimenez, Olivier, Kéry, Marc, Kim, Eun Jung, Lennert‐Cody, Cleridy, Magnusson, Arni, Martell, Steve, Nash, John, Nielsen, Anders, and Regetz, Jim more...
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ECOLOGICAL model (Communication) ,ESTIMATION theory ,EXPERIENCE curve ,ECOLOGISTS ,STOCHASTIC systems - Abstract
Ecologists often use nonlinear fitting techniques to estimate the parameters of complex ecological models, with attendant frustration. This paper compares three open-source model fitting tools and discusses general strategies for defining and fitting models., R is convenient and (relatively) easy to learn, AD Model Builder is fast and robust but comes with a steep learning curve, while BUGS provides the greatest flexibility at the price of speed., Our model-fitting suggestions range from general cultural advice (where possible, use the tools and models that are most common in your subfield) to specific suggestions about how to change the mathematical description of models to make them more amenable to parameter estimation., A companion web site (https://groups.nceas.ucsb.edu/nonlinear-modeling/projects) presents detailed examples of application of the three tools to a variety of typical ecological estimation problems; each example links both to a detailed project report and to full source code and data. [ABSTRACT FROM AUTHOR] more...
- Published
- 2013
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9. Assessing individual heterogeneity using model selection criteria: how many mixture components in capture-recapture models?
- Author
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Cubaynes, Sarah, Lavergne, Christian, Marboutin, Eric, and Gimenez, Olivier
- Subjects
ECOLOGICAL heterogeneity ,BAYESIAN analysis ,ECOLOGY ,BIOLOGICAL evolution ,ESTIMATION theory ,WOLVES - Abstract
1. Capture-recapture mixture models are important tools in evolution and ecology to estimate demographic parameters and abundance while accounting for individual heterogeneity. A key step is to select the correct number of mixture components i) to provide unbiased estimates that can be used as reliable proxies of fitness or ingredients in management strategies and ii) classify individuals into biologically meaningful classes. However, there is no consensus method in the statistical literature for selecting the number of components. 2. In ecology, most studies rely on the Akaike Information Criterion (AIC) and the Bayesian Information Criterion (BIC) that has recently gained attention in ecology. The Integrated Completed Likelihood criterion (ICL; IEEE Transactions on Pattern Analysis and Machine Intelligence, 2000, 22, 719) was specifically developed to favour well-separated components, but its use has never been investigated in ecology. 3. We compared the performance of AIC, BIC and ICL for selecting the number of components with regard to a) bias and accuracy of survival and detection estimates and b) success in selecting the true number of components using extensive simulations and data on wolf ( Canis lupus) that were used for management through survival and abundance estimation. 4. Bias in survival and detection estimates was <0.02 for both AIC and BIC, and more than 0.09 for ICL, while mean square error was <0.05 for all criteria. As expected, bias increased as heterogeneity increased. Success rates of AIC and BIC in selecting the 'true' number of components were better than ICL (68% for AIC, 58% for BIC, and 16% for ICL). As the degree of heterogeneity increased, AIC (and BIC in a lesser extent) overestimated the number of components, while ICL often underestimated this number. For the wolf study, the 2-class model was selected by BIC and ICL, while AIC could not decide between the 2- and 3-class models. 5. We recommend using AIC or BIC when the aim is to estimate parameters. Regarding classification, we suggest taking the classification quality into account by using ICL in conjunction with BIC, pending further work to adapt its penalty term for capture-recapture data. [ABSTRACT FROM AUTHOR] more...
- Published
- 2012
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10. Testing hypotheses in evolutionary ecology with imperfect detection: capture–recapture structural equation modeling.
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Cubaynes, Sarah, Doutrelant, Claire, Grégoire, Arnaud, Perret, Philippe, Faivre, Bruno, and Gimenez, Olivier
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BIRD populations , *BLACKBIRD behavior , *STATE-space methods , *STRUCTURAL equation modeling , *PARAMETER estimation , *MONTE Carlo method - Abstract
Studying evolutionary mechanisms in natural populations often requires testing multifactorial scenarios of causality involving direct and indirect relationships among individual and environmental variables. It is also essential to account for the imperfect detection of individuals to provide unbiased demographic parameter estimates. To cope with these issues, we developed a new approach combining structural equation models with capture-recapture models (CR-SEM) that allows the investigation of competing hypotheses about individual and environmental variability observed in demographic parameters. We employ Markov chain Monte Carlo sampling in a Bayesian framework to (I) estimate model parameters, (2) implement a model selection procedure to evaluate competing hypotheses about causal mechanisms, and (3) assess the fit of models to data using posterior predictive checks. We illustrate the value of our approach using two case studies on wild bird populations. We first show that CR-SEM can be useful to quantify the action of selection on a set of phenotypic traits with an analysis of selection gradients on morphological traits in Common Blackbirds (Turdus merula). In a second case study on Blue Tits (Cyanistes caeruleus), we illustrate the use of CR-SEM to study evolutionary trade-offs in the wild, while accounting for varying environmental conditions. [ABSTRACT FROM AUTHOR] more...
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- 2012
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11. Capture-recapture population growth rate as a robust tool against detection heterogeneity for population management.
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Marescot, Lucile, Pradel, Roger, Duchamp, Christophe, Cubaynes, Sarah, Marboutin, Eric, Choquet, Re´mi, Miquel, Christian, and Gimenez, Olivier
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WOLVES ,ECOLOGICAL heterogeneity ,ANIMAL populations ,ANIMAL population density - Abstract
The article presents the study which shows that the estimation of the population growth rate is robust to individual detection heterogeneity (IDH). The study analyzed the wolf data in France to estimate population growth rate using capture-recapture (CR) models accounting for IDH. It is concluded that the bias in population growth rate increased with detection heterogeneity but was low whether CR model used with IDH or not. more...
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- 2011
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12. Importance of Accounting for Detection Heterogeneity When Estimating Abundance: the Case of French Wolves.
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CUBAYNES, SARAH, PRADEL, ROGER, CHOQUET, RÉMI, DUCHAMP, CHRISTOPHE, GAILLARD, JEAN‐MICHEL, LEBRETON, JEAN‐DOMINIQUE, MARBOUTIN, ERIC, MIQUEL, CHRISTIAN, REBOULET, ANNE‐MARIE, POILLOT, CAROLE, TABERLET, PIERRE, and GIMENEZ, OLIVIER more...
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WOLVES , *HETEROGENEITY , *ECOLOGICAL heterogeneity , *DNA , *FECES , *ENVIRONMENTAL management , *LANDSCAPE protection ,ANIMAL research - Abstract
Assessing conservation strategies requires reliable estimates of abundance. Because detecting all individuals is most often impossible in free-ranging populations, estimation procedures have to account for a <1 detection probability. Capture–recapture methods allow biologists to cope with this issue of detectability. Nevertheless, capture–recapture models for open populations are built on the assumption that all individuals share the same detection probability, although detection heterogeneity among individuals has led to underestimating abundance of closed populations. We developed multievent capture–recapture models for an open population and proposed an associated estimator of population size that both account for individual detection heterogeneity (IDH). We considered a two-class mixture model with weakly and highly detectable individuals to account for IDH. In a noninvasive capture–recapture study of wolves we based on genotypes identified in feces and hairs, we found a large underestimation of population size (27% on average) occurred when IDH was ignored. [ABSTRACT FROM AUTHOR] more...
- Published
- 2010
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13. Will central Wyoming elk stop migrating to Yellowstone, and should we care?
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Massey, Jack, Cubaynes, Sarah, and Coulson, Tim
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ANIMAL migration , *SEDENTARY behavior , *FORAGE , *PREDATORY animals - Abstract
The article presents information on the migratory and sedentary strategy adopted by the elk for the fitness and access to high quality forage that allows them to escape from predators. It mentions that a negative impact on migratory elk has been noticed due to the environmental changes in the U.S. Greater Yellowstone Ecosystem and also adds that a powerful long-term study on population of resident and migratory elk is required to the understand them. more...
- Published
- 2013
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