17 results on '"Nater, Chloé R."'
Search Results
2. Rewriting results sections in the language of evidence
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Muff, Stefanie, Nilsen, Erlend B., O’Hara, Robert B., and Nater, Chloé R.
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- 2022
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3. Redefining 'state‐of‐the‐art' for integrated population models with immigration.
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Nater, Chloé R.
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GAUSSIAN processes , *VITAL statistics , *ANIMAL ecology , *EMIGRATION & immigration , *TIME perception , *MARINE mammals - Abstract
Research Highlight: Christian, M., Oosthuizen, W. C., Bester, M. N., & de Bruyn, P. N. (2024). Robustly estimating the demographic contribution of immigration: Simulation, sensitivity analysis and seals. Journal of Animal Ecology. https://doi.org/10.1111/1365‐2656.14053. Immigration can have profound consequences for local population dynamics and demography, but collecting data to accurately quantifying it is challenging. The recent rise of integrated population models (IPMs) offers an alternative by making it possible to estimate immigration without the need for explicit data, and to quantify its contribution to population dynamics through transient Life Table Response Experiments (tLTREs). Simulation studies have, however, highlighted that this approach can be prone to bias and overestimation. In their new study, Christian et al. address one of the root causes of this issue by improving the estimation of time variation in vital rates and immigration using Gaussian processes in lieu of traditionally used temporal random effects. They demonstrate that IPM‐tLTRE frameworks with Gaussian processes produce more accurate and less biased estimates of immigration and its contribution to population dynamics and illustrate the applicability of this approach using a long‐term data set on elephant seals (Mirounga leonida). Results are validated with a simulation study and suggest that immigration of breeding females has been central for population recovery of elephant seals despite the species' high female site fidelity. Christian et al. thus present new insights into population regulation of long‐lived marine mammals and highlight the potential for using Gaussian process priors in IPMs. They also illustrate a suite of 'best practices' for state‐of‐the‐art IPM‐tLTRE analyses and provide an inspirational example for the kind of ecological modelling workflow that can be invaluable not just as a starting point for fellow ecologists picking up or improving their own IPM‐tLTRE analyses, but also for teaching and in contexts where model estimates are used for informing management and conservation decision‐making. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Density feedbacks mediate effects of environmental change on population dynamics of a semidesert rodent
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Nater, Chloé R., van Benthem, Koen J., Canale, Cindy I., Schradin, Carsten, and Ozgul, Arpat
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- 2018
5. Individual heterogeneity and early life conditions shape growth in a freshwater top predator
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Nater, Chloé R., Rustadbakken, Atle, Ergon, Torbjørn, Langangen, Øystein, Moe, S. Jannicke, Vindenes, Yngvild, Vøllestad, Leif Asbjørn, and Aass, Per
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- 2018
6. Spatial consistency in drivers of population dynamics of a declining migratory bird.
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Nater, Chloé R., Burgess, Malcolm D., Coffey, Peter, Harris, Bob, Lander, Frank, Price, David, Reed, Mike, and Robinson, Robert A.
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BIRD populations , *MIGRATORY birds , *BIRD declines , *POPULATION dynamics , *DEMOGRAPHIC change , *BIRD breeding , *VITAL statistics - Abstract
Many migratory species are in decline across their geographical ranges. Single‐population studies can provide important insights into drivers at a local scale, but effective conservation requires multi‐population perspectives. This is challenging because relevant data are often hard to consolidate, and state‐of‐the‐art analytical tools are typically tailored to specific datasets.We capitalized on a recent data harmonization initiative (SPI‐Birds) and linked it to a generalized modelling framework to identify the demographic and environmental drivers of large‐scale population decline in migratory pied flycatchers (Ficedula hypoleuca) breeding across Britain.We implemented a generalized integrated population model (IPM) to estimate age‐specific vital rates, including their dependency on environmental conditions, and total and breeding population size of pied flycatchers using long‐term (34–64 years) monitoring data from seven locations representative of the British breeding range. We then quantified the relative contributions of different vital rates and population structure to changes in short‐ and long‐term population growth rate using transient life table response experiments (LTREs).Substantial covariation in population sizes across breeding locations suggested that change was the result of large‐scale drivers. This was supported by LTRE analyses, which attributed past changes in short‐term population growth rates and long‐term population trends primarily to variation in annual survival and dispersal dynamics, which largely act during migration and/or nonbreeding season. Contributions of variation in local reproductive parameters were small in comparison, despite sensitivity to local temperature and rainfall within the breeding period.We show that both short‐ and long‐term population changes of British breeding pied flycatchers are likely linked to factors acting during migration and in nonbreeding areas, where future research should be prioritized. We illustrate the potential of multi‐population analyses for informing management at (inter)national scales and highlight the importance of data standardization, generalized and accessible analytical tools, and reproducible workflows to achieve them. [ABSTRACT FROM AUTHOR]
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- 2023
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7. A 50-year series of mark-recapture data of large-sized brown trout (Salmo trutta) from Lake Mjøsa, Norway
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Moe, S. Jannicke, Nater, Chloé R., Rustadbakken, Atle, Vøllestad, L. Asbjørn, Lund, Espen, Qvenild, Tore, Hegge, Ola, and Aass, Per
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Individual-based mark-recapture data from animal population provide a wealth of opportunities for studies, such as individual variation in vital rates ( e.g . survival and reproduction) the links between vital rates and population dynamics. However, maintaining the collection of individual-based data over long time periods comes with large logistic efforts and costs, and studies spanning over decades are therefore rare. Salmonid fishes are of high ecological, cultural, and economical value, but many native wild populations remain in decline. Conservation concerns are particularly great for migratory salmonids as local adaptations and long life spans make them very vulnerable to environmental changes and habitat modifications, e.g., due to hydroelectric power production. This paper describes a unique long-term mark-recapture data set from a land-locked population of large-sized, piscivorous brown trout ( Salmo trutta ) in Norway: the Hunder trout, named after the main water fall (Hunderfossen) in its spawning river. During the period 1966 to 2017, nearly 15,000 Hunder trout have been captured and individually marked during their spawning migration from Lake Mjøsa to the river Gubrandsdalslågen. Fish were first captured and marked while passing a fish ladder within the hydroelectric dam at the Hunderfossen waterfall, and more than 4,000 were later recaptured there alive and/or reported as dead elsewhere. In combination with related life-history and environmental data, these data can be used to gain insights into a variety of questions regarding management and conservation of migratory salmonid populations. In this data paper, we describe (1) a database containing observations on captures and related life-history data obtained from scales (the SUSTAIN trout database), and (2) a publicly available dataset extracted from this database for analysis of survival (the SUSTAIN trout survival dataset).
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- 2019
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8. Joint reply to 'Rewriting results in the language of compatibility' by V. Amrhein and S. Greenland, and to 'The evidence contained in the P-value is context dependent' by F. Hartig and F. Barraquand
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Muff, Stefanie, Nilsen, Erlend B., Nater, Chloé R., and O’Hara, Robert B.
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- 2022
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9. Efficient use of harvest data: a size‐class‐structured integrated population model for exploited populations.
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Gamelon, Marlène, Nater, Chloé R., Baubet, Éric, Besnard, Aurélien, Touzot, Laura, Gaillard, Jean‐Michel, Lebreton, Jean‐Dominique, and Gimenez, Olivier
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WILD boar hunting , *ANIMAL populations , *WILD boar , *INFORMATION society , *POPULATION dynamics - Abstract
Many animal populations are subject to hunting or fishing in the wild. Detailed knowledge of demographic parameters (e.g. survival, reproduction) and temporal dynamics of such populations is crucial for sustainable management. Despite their relevance for management decisions, structure and size of exploited populations are often not known, and data limited. Recently, joint analysis of different types of demographic data, such as population counts, reproductive data and capture–mark–recapture data, within integrated population models (IPMs) has gained much popularity as it may allow estimating population size and structure, as well as key demographic rates, while fully accounting for uncertainty. IPMs built so far for exploited populations have typically been built as age‐structured population models. However, the age of harvested individuals is usually difficult and/or costly to assess and therefore often not available. Here, we introduce an IPM structured by body size classes, which allows making efficient use of data commonly available in exploited populations for which accurate information on age is often missing. The model jointly analyzes size‐at‐harvest data, capture–mark–recapture–recovery data and reproduction data from necropsies, and we illustrate its applicability in a case study involving heavily hunted wild boar. This species has increased in abundance over the last decades despite intense harvest, and the IPM analysis provides insights into the roles of natural mortality, body growth, maturation schedules and reproductive output in compensating for the loss of individuals to hunting. Early maturation and high reproductive output contributed to wild boar population persistence despite a strong hunting pressure. We thus demonstrate the potential of size‐class‐structured IPMs as tools to investigate the dynamics of exploited populations with limited information on age, and highlight both the applicability of this framework to other species and its potential for follow‐up analyses highly relevant to management. [ABSTRACT FROM AUTHOR]
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- 2021
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10. Connecting the data landscape of long‐term ecological studies: The SPI‐Birds data hub.
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Culina, Antica, Adriaensen, Frank, Bailey, Liam D., Burgess, Malcolm D., Charmantier, Anne, Cole, Ella F., Eeva, Tapio, Matthysen, Erik, Nater, Chloé R., Sheldon, Ben C., Sæther, Bernt‐Erik, Vriend, Stefan J. G., Zajkova, Zuzana, Adamík, Peter, Aplin, Lucy M., Angulo, Elena, Artemyev, Alexandr, Barba, Emilio, Barišić, Sanja, and Belda, Eduardo
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METADATA ,DATA integration ,COMMUNITY involvement ,DATA management ,DATA integrity ,LANDSCAPES ,CLIMATE change ,AVIAN influenza - Abstract
The integration and synthesis of the data in different areas of science is drastically slowed and hindered by a lack of standards and networking programmes. Long‐term studies of individually marked animals are not an exception. These studies are especially important as instrumental for understanding evolutionary and ecological processes in the wild. Furthermore, their number and global distribution provides a unique opportunity to assess the generality of patterns and to address broad‐scale global issues (e.g. climate change).To solve data integration issues and enable a new scale of ecological and evolutionary research based on long‐term studies of birds, we have created the SPI‐Birds Network and Database (www.spibirds.org)—a large‐scale initiative that connects data from, and researchers working on, studies of wild populations of individually recognizable (usually ringed) birds. Within year and a half since the establishment, SPI‐Birds has recruited over 120 members, and currently hosts data on almost 1.5 million individual birds collected in 80 populations over 2,000 cumulative years, and counting.SPI‐Birds acts as a data hub and a catalogue of studied populations. It prevents data loss, secures easy data finding, use and integration and thus facilitates collaboration and synthesis. We provide community‐derived data and meta‐data standards and improve data integrity guided by the principles of Findable, Accessible, Interoperable and Reusable (FAIR), and aligned with the existing metadata languages (e.g. ecological meta‐data language).The encouraging community involvement stems from SPI‐Bird's decentralized approach: research groups retain full control over data use and their way of data management, while SPI‐Birds creates tailored pipelines to convert each unique data format into a standard format. We outline the lessons learned, so that other communities (e.g. those working on other taxa) can adapt our successful model. Creating community‐specific hubs (such as ours, COMADRE for animal demography, etc.) will aid much‐needed large‐scale ecological data integration. [ABSTRACT FROM AUTHOR]
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- 2021
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11. Response to ‘Why P values are not measures of evidence’ by D. Lakens
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Muff, Stefanie, Nilsen, Erlend B., O’Hara, Robert B., and Nater, Chloé R.
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- 2022
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12. Contributions from terrestrial and marine resources stabilize predator populations in a rapidly changing climate.
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Nater, Chloé R., Eide, Nina E., Pedersen, Åshild Ø., Yoccoz, Nigel G., and Fuglei, Eva
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MARINE resources ,DEMOGRAPHIC change ,PREDATION ,CLIMATE change ,ANIMAL populations ,ARCTIC fox ,VITAL statistics - Abstract
Climate change has different and sometimes divergent effects on terrestrial and marine food webs, and in coastal ecosystems, these effects are tightly interlinked. Responses of opportunistic coastal predators and scavengers to climate change may thus be complex and potentially highly flexible, and can simultaneously serve as indicators of, and have profound impacts on, lower trophic levels. Gaining mechanistic understanding of these responses is therefore important, but often not feasible due to lack of long‐term data from marked individuals. Here, we used a Bayesian integrated population model (IPM) to elucidate the effects of arctic warming and concurrent changes in terrestrial and marine resource availability on population dynamics of the opportunistic arctic fox (Vulpes lagopus) in Svalbard. Joint analysis of four types of data (den survey, age‐at‐harvest, placental scars, mark‐recovery) revealed relatively stable population size and age structure over the last 22 yr (1997–2019) despite rapid environmental change linked to climate warming. This was related to the fact that terrestrial resources (reindeer carcasses, geese) became more abundant while the availability of marine resources (seal pups/carrion) decreased, and was driven by divergent trends in different vital rates (e.g., increased pregnancy rate but decreased pup survival). Balanced contributions of survival vs. reproduction and of immigration vs. local demography further stabilized population size. Our study thus sheds light on the mechanisms underlying population dynamics of opportunistic carnivores exploiting terrestrial and marine resources and suggests that exploitation of resources across different ecosystems can buffer predators against climate change. Additionally, it highlights the large potential of IPMs as tools to understand and predict the effects of environmental change on wildlife populations, even when data on marked individuals are sparse. [ABSTRACT FROM AUTHOR]
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- 2021
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13. Size‐ and stage‐dependence in cause‐specific mortality of migratory brown trout.
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Nater, Chloé R., Vindenes, Yngvild, Aass, Per, Cole, Diana, Langangen, Øystein, Moe, S. Jannicke, Rustadbakken, Atle, Turek, Daniel, Vøllestad, Leif Asbjørn, Ergon, Torbjørn, and Koons, David
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BROWN trout , *BODY size , *MORTALITY , *TIME series analysis , *EVIDENCE-based management , *VITAL statistics - Abstract
Evidence‐based management of natural populations under strong human influence frequently requires not only estimates of survival but also knowledge about how much mortality is due to anthropogenic vs. natural causes. This is the case particularly when individuals vary in their vulnerability to different causes of mortality due to traits, life history stages, or locations.Here, we estimated harvest and background (other cause) mortality of landlocked migratory salmonids over half a century. In doing so, we quantified among‐individual variation in vulnerability to cause‐specific mortality resulting from differences in body size and spawning location relative to a hydropower dam.We constructed a multistate mark–recapture model to estimate harvest and background mortality hazard rates as functions of a discrete state (spawning location) and an individual time‐varying covariate (body size). We further accounted for among‐year variation in mortality and migratory behaviour and fit the model to a unique 50‐year time series of mark–recapture–recovery data on brown trout (Salmo trutta) in Norway.Harvest mortality was highest for intermediate‐sized trout, and outweighed background mortality for most of the observed size range. Background mortality decreased with body size for trout spawning above the dam and increased for those spawning below. All vital rates varied substantially over time, but a trend was evident only in estimates of fishers' reporting rate, which decreased from over 50% to less than 10% throughout the study period.We highlight the importance of body size for cause‐specific mortality and demonstrate how this can be estimated using a novel hazard rate parameterization for mark–recapture models. Our approach allows estimating effects of individual traits and environment on cause‐specific mortality without confounding, and provides an intuitive way to estimate temporal patterns within and correlation among different mortality sources. [ABSTRACT FROM AUTHOR]
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- 2020
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14. Long-term mark-recapture and growth data for large-sized migratory brown trout (Salmo trutta) from Lake Mjøsa, Norway.
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Moe, S. Jannicke, Nater, Chloé R., Rustadbakken, Atle, Vøllestad, L. Asbjørn, Lund, Espen, Qvenild, Tore, Hegge, Ola, and Aass, Per
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BROWN trout ,AQUATIC ecology ,MIGRATORY fishes ,SCLEROCHRONOLOGY ,FRESHWATER ecology - Abstract
Long-term data from marked animals provide a wealth of opportunities for studies with high relevance to both basic ecological understanding and successful management in a changing world. The key strength of such data is that they allow us to quantify individual variation in vital rates (e.g. survival, growth, reproduction) and then link it mechanistically to dynamics at the population level. However, maintaining the collection of individual-based data over long time periods comes with large logistic efforts and costs and studies spanning over decades are therefore rare. This is the case particularly for migratory aquatic species, many of which are in decline despite their high ecological, cultural and economical value. [ABSTRACT FROM AUTHOR]
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- 2020
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15. Interactive effects of exogenous and endogenous factors on demographic rates of an African rodent.
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Nater, Chloé R., Canale, Cindy I., Benthem, Koen J., Yuen, Chi‐Hang, Schoepf, Ivana, Pillay, Neville, Ozgul, Arpat, and Schradin, Carsten
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MAMMAL population estimates , *POPULATION density , *POPULATION dynamics , *RODENTS , *MAMMALS - Abstract
Exogenous and endogenous environmental factors can have simultaneous additive as well as interacting effects on life-history traits. Ignoring such interactions can lead to a biased understanding of variability in demographic rates and consequently population dynamics. These interactions have been the focus of decades-long debates on the mechanisms underlying small mammal population fluctuations. They have often been studied indirectly through seasonal effects, but studies considering them directly and more mechanistically are rare. We investigated the joint effects of exogenous (temperature, food availability) and endogenous (population density) factors on the demographic rates of a group-living diurnal rodent, the African striped mouse Rhabdomys pumilio using nine-year mark-recapture data from a population in the Succulent Karoo, South Africa. In general, higher temperatures and lower food availability were associated with higher survival, whereas high population densities were either beneficial or detrimental to survival depending on interacting food availability. High reproductive rates were related to lower temperatures, higher food availability and lower population density, and interactions among environmental factors mediated the strength of these relationships. Our study highlights the complex ways in which different environmental factors can interact to shape demographic rates and emphasizes the importance of explicitly including interactions among exogenous and endogenous factors into studies of population dynamics. [ABSTRACT FROM AUTHOR]
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- 2016
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16. Multifaceted density dependence: Social structure and seasonality effects on Serengeti lion demography.
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Conquet, Eva, Paniw, Maria, Borrego, Natalia, Nater, Chloé R., Packer, Craig, and Ozgul, Arpat
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LIONS , *VITAL statistics , *POPULATION dynamics , *POPULATION density , *SOCIAL influence - Abstract
Interactions between density and environmental conditions have important effects on vital rates and consequently on population dynamics and can take complex pathways in species whose demography is strongly influenced by social context, such as the African lion, Panthera leo. In populations of such species, the response of vital rates to density can vary depending on the social structure (e.g. effects of group size or composition). However, studies assessing density dependence in populations of lions and other social species have seldom considered the effects of multiple socially explicit measures of density, and—more particularly for lions—of nomadic males. Additionally, vital‐rate responses to interactions between the environment and various measures of density remain largely uninvestigated. To fill these knowledge gaps, we aimed to understand how a socially and spatially explicit consideration of density (i.e. at the local scale) and its interaction with environmental seasonality affect vital rates of lions in the Serengeti National Park, Tanzania. We used a Bayesian multistate capture–recapture model and Bayesian generalized linear mixed models to estimate lion stage‐specific survival and between‐stage transition rates, as well as reproduction probability and recruitment, while testing for season‐specific effects of density measures at the group and home‐range levels. We found evidence for several such effects. For example, resident‐male survival increased more strongly with coalition size in the dry season compared with the wet season, and adult‐female abundance affected subadult survival negatively in the wet season, but positively in the dry season. Additionally, while our models showed no effect of nomadic males on adult‐female survival, they revealed strong effects of nomads on key processes such as reproduction and takeover dynamics. Therefore, our results highlight the importance of accounting for seasonality and social context when assessing the effects of density on vital rates of Serengeti lions and of social species more generally. [ABSTRACT FROM AUTHOR]
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- 2024
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17. Density feedbacks mediate effects of environmental change on population dynamics of a semidesert rodent
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Cindy I. Canale, Chloé R. Nater, Arpat Ozgul, Koen J. van Benthem, Carsten Schradin, Department of Evolutionary Biology and Environmental Studies, University of Zurich, Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences [Oslo], Faculty of Mathematics and Natural Sciences [Oslo], University of Oslo (UiO)-University of Oslo (UiO)-Faculty of Mathematics and Natural Sciences [Oslo], University of Oslo (UiO)-University of Oslo (UiO), School of Animal, Plant & Environmental Sciences, University of the Witwatersrand [Johannesburg] (WITS), Département Ecologie, Physiologie et Ethologie (DEPE-IPHC), Institut Pluridisciplinaire Hubert Curien (IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Childs, Dylan, and Nater, Chloé R
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0106 biological sciences ,Environmental change ,Evolution ,Climate Change ,Population ,Population Dynamics ,Climate change ,Rodentia ,Biology ,010603 evolutionary biology ,01 natural sciences ,Population density ,10127 Institute of Evolutionary Biology and Environmental Studies ,Mice ,Behavior and Systematics ,Animals ,education ,Ecology, Evolution, Behavior and Systematics ,ComputingMilieux_MISCELLANEOUS ,Demography ,2. Zero hunger ,Population Density ,education.field_of_study ,Ecology ,010604 marine biology & hydrobiology ,Population size ,15. Life on land ,Density dependence ,1105 Ecology, Evolution, Behavior and Systematics ,Population model ,13. Climate action ,[SDE]Environmental Sciences ,570 Life sciences ,biology ,590 Animals (Zoology) ,Animal Science and Zoology ,Female ,Vital rates ,1103 Animal Science and Zoology - Abstract
1. Population dynamics are the result of an interplay between extrinsic and intrinsic environmental drivers. Predicting the effects of environmental change on wildlife populations therefore requires a thorough understanding of the mechanisms through which different environmental drivers interact to generate changes in population size and structure. 2. In this study, we disentangled the roles of temperature, food availability and population density in shaping short‐ and long‐term population dynamics of the African striped mouse, a small rodent inhabiting a semidesert with high intra‐ and interannual variation in environmental conditions. 3. We parameterized a female‐only stage‐structured matrix population model with vital rates depending on temperature, food availability and population density, using monthly mark–recapture data from 1609 mice trapped over 9 years (2005–2014). We then applied perturbation analyses to determine relative strengths and demographic pathways of these drivers in affecting population dynamics. Furthermore, we used stochastic population projections to gain insights into how three different climate change scenarios might affect size, structure and persistence of this population. 4. We identified food availability, acting through reproduction, as the main driver of changes in both short‐ and long‐term population dynamics. This mechanism was mediated by strong density feedbacks, which stabilized the population after high peaks and allowed it to recover from detrimental crashes. Density dependence thus buffered the population against environmental change, and even adverse climate change scenarios were predicted to have little effect on population persistence (extinction risk over 100 years
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- 2018
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