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Neophobia is an important personality trait that allows animals to minimize exposure to threat. We investigated the existence of consistent individual differences in the level of neophobia in captive roe deer, Capreolus capreolus, using an experimental set-up. Our main objective was to explore the link between an individual's level of neophobia with behavioural and physiological responses measured during a stressful situation, i.e. capture and restraint, to facilitate characterization of neophobia in the wild. We found that the probability of initiating a feeding bout and the feeding efficiency over bouts both decreased in the presence of a novel object. However, there was pronounced variation in the degree to which individuals were affected by the experimental treatment. First, feeding efficiency decreased the most among individuals that reacted less markedly to an acutely stressful situation (capture). Second, latency between the first visit and the first feeding bout increased the most among individuals that had a higher concentration of fructosamine in their blood, an indicator of chronic stress. Our results indicate that individuals that are more neophobic (high latency to first feeding bout and low feeding efficiency in the presence of a novel object) are also less proactive (low behavioural response to capture, high levels of fructosamine), suggesting the existence of a behavioural syndrome. We conclude that behavioural and physiological parameters measured during capture provide reliable indicators of neophobia for roe deer, providing an exciting new avenue for the study of animal personality in the wild.

International audience; Gender-related inequalities in scientific careers are widespread, evidenced by the attrition of women along the different stages of the promotion ladder. We studied the interwoven personal and professional trajectories of researchers in ecology and compared these trajectories between France and Norway. Given their differing welfare state policies and work/family regimes, we expected contrasts in the depth and modalities of the gender gap. We focused on the career consequences of time-use inequalities in the workplace and in the private sphere (domestic tasks and parental care). We find a more frequent assignment of women to less-valued tasks at work (e.g. teaching) and pronounced gender differences in the involvement in domestic and parental tasks, especially in France. Age at promotion and probability to be promoted differed between gender in both countries and more so in France, women being less promoted and promoted later than men. This gender gap was particularly discriminating women with children, when they were either single or with a partner who also was a researcher. These differences are mainly due to a lower scientific productivity of women when they get children. These analyses raise a number of questions on welfare policies and on the definition of academic standards of peer judgment within local employment policies in universities.

The successful management of large herbivores requires the monitoring of a set of indicators of ecological change (IEC) describing animal performance, herbivore impact on habitat and relative animal abundance. Roaring counts during the rut have often been used to assess the abundance of red deer Cervus elaphus populations, but a formal evaluation of this method is still lacking. In this paper, we examined the usefulness of the number of red deer recorded during roaring counts for managing red deer populations. Using standardised spotlight counts applied for the monitoring of red deer at La Petite Pierre, France, as a reference method, we found that roaring counts did not correlate with spotlight counts. Moreover, we did not find any evidence that roaring counts decreased with increasing number of male and female red deer harvested in the reserve during the previous hunting season. We thus conclude that managers should not rely on roaring counts for managing red deer populations.

International audience; How populations respond to climate change depends on the interplay between life history, resource availability, and the intensity of the change. Roe deer are income breeders, with high levels of allocation to reproduction, and are hence strongly constrained by the availability of high quality resources during spring. We investigated how recent climate change has influenced demographic processes in two populations of this widespread species. Spring began increasingly earlier over the study, allowing us to identify 2 periods with contrasting onset of spring. Both populations grew more slowly when spring was early. As expected for a long-lived and iteroparous species, adult survival had the greatest potential impact on population growth. Using perturbation analyses, we measured the relative contribution of the demographic parameters to observed variation in population growth, both within and between periods and populations. Within periods, the identity of the critical parameter depended on the variance in growth rate, but variation in recruitment was the main driver of observed demographic change between periods of contrasting spring earliness. Our results indicate that roe deer in forest habitats cannot currently cope with increasingly early springs. We hypothesise that they should shift their distribution to richer, more heterogeneous landscapes to offset energetic requirements during the critical rearing stage.

Understanding how the natural world will be impacted by environmental change over the coming decades is one of the most pressing challenges facing humanity. Addressing this challenge is difficult because environmental change can generate both population level plastic and evolutionary responses, with plastic responses being either adaptive or non-adaptive. We develop an approach that links quantitative genetic theory with data-driven structured models to allow prediction of population responses to environmental change via plasticity and adaptive evolution. After introducing general new theory, we construct a number of example models to demonstrate that evolutionary responses to environmental change over the short-term will be considerably slower than plastic responses, and that the rate of adaptive evolution to a new environment depends upon whether plastic responses are adaptive or non-adaptive. Parameterization of the models we develop requires information on genetic and phenotypic variation and demography that will not always be available, meaning that simpler models will often be required to predict responses to environmental change. We consequently develop a method to examine whether the full machinery of the evolutionarily explicit models we develop will be needed to predict responses to environmental change, or whether simpler non-evolutionary models that are now widely constructed may be sufficient.

While it is commonly believed that animals live longer in zoos than in the wild, this assumption has rarely been tested. We compared four survival metrics (longevity, baseline mortality, onset of senescence and rate of senescence) between both sexes of free-ranging and zoo populations of more than 50 mammal species. We found that mammals from zoo populations generally lived longer than their wild counterparts (84% of species). The effect was most notable in species with a faster pace of life (i.e. a short life span, high reproductive rate and high mortality in the wild) because zoos evidently offer protection against a number of relevant conditions like predation, intraspecific competition and diseases. Species with a slower pace of life (i.e. a long life span, low reproduction rate and low mortality in the wild) benefit less from captivity in terms of longevity; in such species, there is probably less potential for a reduction in mortality. These findings provide a first general explanation about the different magnitude of zoo environment benefits among mammalian species, and thereby highlight the effort that is needed to improve captive conditions for slow-living species that are particularly susceptible to extinction in the wild.

According to recent empirical studies, reproductive senescence, the decline in reproductive success with increasing age, seems to be nearly ubiquitous in the wild. However, a clear understanding of the evolutionary causes and consequences of reproductive senescence is still lacking and requires new and integrative approaches. After identifying the sequential and complex nature of female reproductive senescence, we show that the relative contributions of physiological decline and alterations in the efficiency of parental care to reproductive senescence remain unknown and need to be assessed in the light of current evolutionary theories of ageing. We demonstrate that, although reproductive senescence is generally studied only from the female viewpoint, age-specific female reproductive success strongly depends on male-female interactions. Thus, a reduction in male fertilization efficiency with increasing age has detrimental consequences for female fitness. Lastly, we call for investigations of the role of environmental conditions on reproductive senescence, which could provide salient insights into the underlying sex-specific mechanisms of reproductive success. We suggest that embracing such directions should allow building new bridges between reproductive senescence and the study of sperm competition, parental care, mate choice and environmental conditions.

Many studies have reported temporal changes in the relative importance of density-dependence and environmental stochasticity in affecting population growth rates, but they typically assume that the predominant factor limiting growth remains constant over long periods of time. Stochastic switches in limiting factors that persist for multiple time-steps have received little attention, but most wild populations may periodically experience such switches. Here, we consider the dynamics of three populations of individually marked bighorn sheep ( Ovis canadensis ) monitored for 24–28 years. Each population experienced one or two distinct cougar ( Puma concolor ) predation events leading to population declines. The onset and duration of predation events were stochastic and consistent with predation by specialist individuals. A realistic Markov chain model confirms that predation by specialist cougars can cause extinction of isolated populations. We suggest that such processes may be common. In such cases, predator–prey equilibria may only occur at large geographical and temporal scales, and are unlikely with increasing habitat fragmentation.

Environmental stochasticity is known to play an important role in life-history evolution, but most general theory assumes a constant environment. In this paper, we examine life-history evolution in a variable environment, by decomposing average individual fitness (measured by the long-run stochastic growth rate) into contributions from average vital rates and their temporal variation. We examine how generation time, demographic dispersion (measured by the dispersion of reproductive events across the lifespan), demographic resilience (measured by damping time), within-year variances in vital rates, within-year correlations between vital rates and between-year correlations in vital rates combine to determine average individual fitness of stylized life histories. In a fluctuating environment, we show that there is often a range of cohort generation times at which the fitness is at a maximum. Thus, we expect ‘optimal’ phenotypes in fluctuating environments to differ from optimal phenotypes in constant environments. We show that stochastic growth rates are strongly affected by demographic dispersion, even when deterministic growth rates are not, and that demographic dispersion also determines the response of life-history-specific average fitness to within- and between-year correlations. Serial correlations can have a strong effect on fitness, and, depending on the structure of the life history, may act to increase or decrease fitness. The approach we outline takes a useful first step in developing general life-history theory for non-constant environments.

Ecological and evolutionary change is generated by variation in individual performance. Biologists have consequently long been interested in decomposing change measured at the population level into contributions from individuals, the traits they express and the alleles they carry. We present a novel method of estimating individual contributions to population growth and changes in distributions of quantitative traits and alleles. An individual's contribution to population growth is an individual's realized annual fitness. We demonstrate how the quantities we develop can be used to address a range of empirical questions, and provide an application to a detailed dataset of Soay sheep. The approach provides results that are consistent with those obtained using lifetime estimates of individual performance, yet is substantially more powerful as it allows lifetime performance to be decomposed into annual survival and fecundity contributions.

International audience; In seasonal environments, parturition of most vertebrates generally occurs within a short time-window each year. This synchrony is generally interpreted as being adaptive, as early born young survive better over the critical season than late born young. Among large herbivores, the factors involved in driving among- and within-individual variation in parturition date are poorly understood. We explored this question by analyzing the relative importance of attributes linked to female quality (longevity, median adult body mass and cohort), time-dependent attributes linked to female condition (reproductive success the previous year, relative annual body mass and offspring cohort (year)), and age in shaping observed variation in parturition date of roe deer. A measure of quality combining the effects of female longevity and median adult body mass accounted for 11% of the observed among-individual variation in parturition date. Females of 2 yr old give birth 5 d later than older females. Our study demonstrates that high quality (heavy and long-lived) females give birth earlier than low quality females. Temporally variable attributes linked to female condition, such as reproductive success in the previous year and relative annual body mass, had no detectable influence on parturition date. We conclude that parturition date, a crucial determinant of reproductive success, is shaped by attributes linked to female quality rather than by time-dependent attributes linked to female condition in income breeders (individuals that rely on current resource intake rather than on accumulated body reserves to offset the increased energy requirements due to reproduction) such as roe deer.

We investigated age-specific variation in survival of dominant individuals in a long-lived and monogamous mammal, the alpine marmot ( Marmota marmota ), from a large dataset collected during a 24-year intensive monitoring of a free-ranging population. We found evidence of actuarial senescence in dominant individuals for both sexes. Survivorship was constant with age until dominant marmots were between 6 and 8 years of age and declined markedly thereafter. No between sex differences occurred in the intensity of actuarial senescence, which might be related to the weak intensity of sexual selection in this socially monogamous mammal. More investigations are needed to know whether cooperative breeding, hibernation, and monogamy, which are key features of the alpine marmot life history, could have shaped the patterns of actuarial senescence we report.

The population growth rate is linked to the distribution of age at death. We demonstrate that this link arises because both the birth and death rates depend on the variance of age-at-death. This bears the prospect to separate the influences of the age patterns of fertility and mortality on population growth rate. Here, we show how the age pattern of death affects population growth. Using this insight we derive a new approximation of the population growth rate that uses the first and second moments of the age-at-death distribution. We apply our new approximation to 46 mammalian life tables (including humans) and show that it is on par with the most prominent other approximations.

Summary 1. Harvest models are often built to explore the sustainability of the dynamics of exploited populations and to help evaluate hunting management scenarios. Age-structured models are commonly used for ungulate population dynamics. However, the age of hunted individuals is usually not recorded, and hunting data often only include body weight and sex limiting the usefulness of traditional models. 2. We propose a new modelling approach that fits data collected by hunters to develop management rules when age is not available. Using wild boar Sus scrofa scrofa as a case study, we built a matrix model structured according to sex and body weight whose output can be directly compared with the observed distribution of hunted individuals among sex and body weight classes. 3. In the face of the current wide scale increase in populations of wild boar, the best feasible option to stop or slow down population growth involves targeting the hunting effort to specific sex and body weight classes. The optimal harvest proportion in the target body weight classes is estimated using sensitivity analyses. 4. The number of individuals shot in each sex and body weight class predicted by our model was closely associated with those recorded in the hunting bag. Increasing the hunting pressure on medium-sized females by 14·6% was the best option to limit growth rate to a target of 0·90. 5. Synthesis and applications. We demonstrate that targeting hunting effort to specific body weight classes could reliably control population growth. Our modelling approach can be applied to any game species where group composition, phenotypic traits or coat colour allows hunters to easily identify sex and body weight classes. This offers a promising tool for applying selective hunting to the management of game species.

Summary 1. Autocorrelation and individual heterogeneity are now considered to reflect biological processes rather than simply being a nuisance requiring to be accounted for. Before using parameter estimates that represent autocorrelation and individual heterogeneity to infer biological processes, a statistical evaluation of their precision and accuracy is required to validate their use. 2. Using simulated data, we evaluated accuracy and precision of temporal autocorrelation and individual heterogeneity estimates provided by different statistical models. We compared estimates across different intensity of individual variation and life histories, and sampling effort. We focused on recurrent binary variables because statistical evaluations of models describing binary processes have often been overlooked although several evolutionary and ecological processes are expressed as binary variables (e.g. probability of annual reproduction, plant annual flowering and detection, seasonal migration decision). 3. Our results showed that autocorrelation and individual heterogeneity were generally better estimated using a ‘time series’ modelling approach, but that a ‘state dependence’ modelling approach also provided fair estimates in most cases. The latter method was even more robust when data sets included missing values. Data sets including missing values or consisting of very short times series resulted in important bias in some instances. 4. Models ignoring either individual heterogeneity or autocorrelation performed poorly, illustrating the fundamental association between these two processes, and demonstrating that the complex structure of autocorrelation and individual heterogeneity patterns is difficult to tackle using simple models. 5. Our work’s major finding is the demonstration that autocorrelation and individual heterogeneity need to be both accounted for to provide reliable estimates even in studies focusing on only one of these processes. Our study also offers a set of practical recommendations for helping researchers modelling these two processes depending on their scientific aims and the structure of their data. Finally, our results illustrate that more research is required for estimating individual heterogeneity when positive temporal autocorrelation is expected because none of the models evaluated provided suitable estimates.

Sympatric populations of species with similar ecology are limited by competition for available resources. While quantifying niche overlap between species in interaction offers a useful description of coexistence patterns, the lack of correspondence between niche overlap and competition prevents any functional interpretation. Using an innovative approach for analysing spatial distributions of individuals from two sympatric species, we aim to fill the gap. We applied our models to data collected on sympatric females of roe deer and red deer. Using the null model approach commonly applied in community ecology, we tested in a first model for deviation from a random distribution of female roe deer in relation to female red deer. We took into account constraints generated by both the marked sedentary habits and habitat use (avoidance of mature forest) of roe deer in this null model. In a second null model, we removed the habitat constraints to avoid any lack of power of our tests. We then compared the overlap index calculated from roe deer and red deer locations with the distribution expected under each of these null models. As we failed to reject the null model in both cases, we tested a third null model simulating an identical distribution of roe deer and red deer home ranges and we rejected it. Our results show that the distribution of female roe deer does not depend on the distribution of female red deer, indicating an absence of competitive interactions between the deer species. This conclusion relies on the application of the null model approach, which provides a suitable way of performing a formal test of interspecific competition rooted in explicitly defined hypotheses, and could not have been reached using simple overlap indices as generally performed when assessing competitive interactions. We thus encourage scientists to apply this null model analysis to population ecology.

Investigating the factors shaping the activity of large herbivores is of prime importance because changes in their activity patterns may indicate physiological stress, which can affect reproduction and survival of individuals, and thereby population growth. Although climatic conditions are known to impact the activity patterns of large herbivores, few studies have investigated this relationship at a fine temporal scale. From a continuous monitoring of activity, we assessed the influence of temperature and wind on the summer activity of female mouflon ( Ovis gmelini musimon Pallas, 1811 × Ovis sp.) facing summer droughts. Females showed a marked bimodal activity pattern, with activity peaks occurring after dawn and before dusk. When temperature increased and wind speed decreased, the morning activity peak occurred earlier, while the evening activity peak was delayed. Hence, under stressing climatic conditions, female mouflon decreased their diurnal activity while increasing their nocturnal activity. However, this nocturnal increase did not prevent the activity rate over 24 h to decrease during hot nonwindy days compared with cool windy days. Although the occurrence of wind mitigated the negative influence of heat on the diurnal activity, wind had no effect at the daily scale. These findings emphasize the importance of working at different temporal scales when assessing the activity patterns of free-ranging vertebrates.

The size and shape of a trophy constitute major determinants of its value. We postulate that the rarity of a species, whatever its causes, also plays a major role in determining its value among hunters. We investigated a role for an Anthropogenic Allee effect in trophy hunting, where human attraction to rarity could lead to an over-exploitative chain reaction that could eventually drive the targeted species to extinction. We performed an inter-specific analysis of trophy prices of 202 ungulate taxa and quantified to what extent morphological characteristics and their rarity accounted for the observed variation in their price. We found that once location and body mass were accounted for, trophies of rare species attain higher prices than those of more common species. By driving trophy price increase, this rarity effect may encourage the exploitation of rare species regardless of their availability, with potentially profound consequences for populations.

Exploitation by humans affects the size and structure of populations. This has evolutionary and demographic consequences that have typically being studied independent of one another. We here applied a framework recently developed applying quantitative tools from population ecology and selection gradient analysis to quantify the selection on a quantitative trait—birth date— through its association with multiple fitness components. From the long-term monitoring (22 years) of a wild boar (Sus scrofa scrofa) population subject to markedly increasing hunting pressure, we found that birth dates have advanced by up to 12 days throughout the study period. During the period of low hunting pressure, there was no detectable selection. However, during the period of high hunting pressure, the selection gradient linking breeding probability in the first year of life to birth date was negative, supporting current life-history theory predicting selection for early births to reproduce within the first year of life with increasing adult mortality.

Summary 1. Demographic tactics within animal populations are shaped by selective pressures. Exploitation exerts additional pressures so that differing demographic tactics might be expected among populations with differences in levels of exploitation. Yet little has been done so far to assess the possible consequences of exploitation on the demographic tactics of mammals, even though such information could influence the choice of effective management strategies. 2. Compared with similar-sized ungulate species, wild boar Sus scrofa has high reproductive capabilities, which complicates population management. Using a perturbation analysis, we investigated how population growth rates (λ) and critical life-history stages differed between two wild boar populations monitored for several years, one of which was heavily harvested and the other lightly harvested. 3. Asymptotic λ was 1·242 in the lightly hunted population and 1·115 in the heavily hunted population, while the ratio between the elasticity of adult survival and juvenile survival was 2·63 and 1·27, respectively. A comparative analysis including 21 other ungulate species showed that the elasticity ratio in the heavily hunted population was the lowest ever observed. 4. Compared with expected generation times of similar-sized ungulates (more than 6 years), wild boar has a fast life-history speed, especially when facing high hunting pressure. This is well illustrated by our results, where generation times were 3·6 years in the lightly hunted population and only 2·3 years in the heavily hunted population. High human-induced mortality combined with non-limiting food resources accounted for the accelerated life history of the hunted population because of earlier reproduction. 5. Synthesis and applications. For wild boar, we show that when a population is facing a high hunting pressure, increasing the mortality in only one age-class (e.g. adults or juveniles) may not allow managers to limit population growth. We suggest that simulations of management strategies based on context-specific demographic models are useful for selecting interventions for population control. This type of approach allows the assessment of population response to exploitation by considering a range of plausible scenarios, improving the chance of selecting appropriate management actions.

Based on 1,053 signs of presence collected between 2002 and 2006 by a network of well-trained observers, we modelled the occurrence of the Eurasian lynx (Lynx lynx) in France using two methods. The Mahalanobis distance factor analysis (MADIFA) provided a measure of habitat suitability based on environmental covariates, and site-occupancy modelling provided estimates of both presence and detection probabilities over time. Environmental covariates included in the site-occupancy modelling markedly improved the fit of the lynx presence model. We found a strong correlation between habitat suitability scores estimated from the MADIFA and probabilities of presence estimated from the site-occupancy modelling, indicating that both methods provided a convergent assessment of lynx potential occurrence.

[Notes_IRSTEA]publié en online first 9 April 2011 [Departement_IRSTEA]Territoires [TR1_IRSTEA]SEDYVIN; International audience; Increasing populations of large herbivores during the last decades have had a major impact on vegetation. While several studies have looked for quantifying this impact in terms of plant biomass, plant survival or financial costs, the potential benefit of using the response of the vegetation to changes in browsing pressure by large herbivores to monitor their populations has been poorly investigated. As getting accurate estimates of density in populations of large herbivores is problematic, the use of indicators measuring the intensity of browsing might offer reliable alternative to managers. From the intensive monitoring of a roe deer population subject to an experimental manipulation of density, we looked for assessing the response of oak to changes of roe deer population size. Using a simple browsing index calculated from field data over 10 years, we found that this oak browsing index linearly increased with increasing population size of roe deer. This suggests that such an oak browsing index might be a reliable indicator of ecological change for monitoring roe deer populations in oak forests with natural regeneration.; L'augmentation des populations de grands herbivores au cours des dernières décennies a eu un impact majeur sur la végétation. Bien que plusieurs études ont analysé cet impact en termes de biomasse végétale, de survie des plantes ou de coûts financiers, l'intérêt que pourrait présenter, pour la gestion des ongulés, les réponses de la végétation à la pression d'herbivorie a jusqu'ici été mal exploité. Comme l'estimation précise de la densité des populations de grands herbivores s'avère délicate, le recours à des indicateurs d'intensité d'abroutissement pourrait offrir une alternative prometteuse aux gestionnaires. À partir d'un suivi expérimental d'une population de chevreuil (Capreolus capreolus) dont la densité a fortement fluctuée au cours du temps, nous avons étudié la réponse du chêne (Quercus petraea) aux variations d'effectifs de cette population. Le calcul d'un indice d'abroutissement annuel du chêne, obtenu à partir des données collectées sur une période de dix ans, nous a permis de montrer que cet indice croit linéairement avec l'effectif de la population de chevreuil. Ce constat nous permet de penser que cet indice d'abroutissement du chêne pourrait constituer un Indicateur de Changement Écologique (ICE) adapté à la gestion des populations de chevreuil dans les massifs forestiers à dominante de régénération naturelle de chêne.

Summary 1. Semi-Markov models explicitly define the distribution of waiting time duration and have been used as a convenient framework for modelling the time spent in one physiological state in previous biological studies. 2. Here, we focus on the modelling of the time spent within a life-cycle stage (e.g. juvenile, adult and old) by individuals over their lifetime from Capture–Mark–Recapture data, which are commonly used to estimate demographic parameters in free-ranging populations. 3. We propose a parametric model (1) with a semi-Markov state, (2) associated to a hazard function and (3) accounting for imperfect detection to assess reliably survival patterns from birth to death. 4. These models indeed outperform models with a linear trend or a quadratic form, often selected as the best model for survival in capture–recapture studies. 5. Moreover, our approach offers the first opportunity to estimate statistically rather than visually the age of the onset of actuarial senescence, associated with confidence intervals. 6. The application of this new approach to the detailed long-term study of survival in roe deer at Trois Fontaines (France) illustrates the relevance of semi-Markov models to assess survival patterns from birth to death.

The positive allometry between antlers and shoulder height reported for cervids has previously been interpreted as resulting from a high male-male competition in large species that form large breeding groups. We aim at revisiting relative antler size variation among deer species by including more species (n = 31) and by testing both direct and indirect influences of different sexual selection proxies on the relative antler length using path analysis. The absence of direct effect of mating tactic on relative antler allometry indicates that the strength of fights does not differ among mating tactics. On the other hand, the main effect of breeding group size is revealed by polygyny. Highly polygynous species have relatively longer antlers than less polygynous ones but the difference in the relative effect of breeding group size on relative antler length is weak. Strong direct effect of breeding group size and indirect effect of mating tactic shaped the observed variation in the relative antler size among deer, suggesting that the amount of male-male competition is the main evolutionary force of antler allometry in cervids.

The development of computers, appropriate statistical methodology and specialized software has induced an explosion in empirical research on vertebrate population dynamics. Many long-term programs have led to impressive datasets and to the publication of hundreds of estimates of vital rates critical to many areas of ecology: evolution of life history strategies, conservation biology, behavioral ecology, population management, etc. Such estimates are still usually available through regular scientific articles, and their use for comparative purposes suffers from several shortcomings: duplication of technical work, lack of evaluation of methodological bias, and difficulties in linking vital rates estimates with other basic traits such as body size. It thus seems it is time to propose a demographic databank to collect the information on vertebrate demography published and being published and make it widely available. The resulting database should become the equivalent for vertebrate demography to what “Genbank” is for DNA sequences. Bird demography has a critical mass of knowledge adequate for a first step. This paper reviews, based on a prototype database, the outline of such a project of demographic database: type of data and estimates stored, assessment of methodology and data quality, data documentation, taxonomical and phylogenetical information, link with other existing biodiversity databases, procedures for depositing information, links with scientific journals, etc. The contours of a collaborative group to launch such a project are also discussed.

Climatic influences on animal populations, mediated by changes in condition-dependent survival or reproduction, have long intrigued ecologists. We analyzed links between winter North Atlantic Oscillations (NAO), a large scale climatic phenomenon affecting weather conditions over the North Atlantic and the Arctic, and average pre-laying body mass in common eiders. Body mass is a good proxy for condition-dependent reproductive output in this species. Time series links were assessed for two eider populations breeding at high latitudes, over a 10- and a 21-year time series. Winter NAO affected body mass in both populations and these effects were easier to detect when changes in the series rhythm were assessed using a novel method based on data discretization and information theory, rather than detection based on changes in amplitude, assessed using traditional linear models. Winter conditions affected body condition of eiders in both populations. Different mechanisms, however, are likely to be involved in the two populations, one being presumably affected by direct effects of climate and the other by effects through the food chain. Therefore, the same species can respond along different pathways to the same large scale climatic pattern, an important consideration when seeking to understand or manage the response of species to present and future climate change.

The extent to which large carnivores compete with hunters for harvestable populations of wild ungulates is a topic of widespread controversy in many areas of the world where carnivore populations are recovering or are reintroduced. Theory predicts that predation impacts should vary with prey density and environmental conditions. To test this prediction, we analyzed trends in an index of population abundance of roe deer (Capreolus capreolus) over 9 y in 144 Norwegian municipalities. The municipalities span a wide range of landscapes and climatic conditions and were associated with a varying degree of Eurasian lynx (Lynx lynx) presence. There was a wide variation in trends of roe deer abundance (estimated long-term average λ ranging from 0.69 to 1.23) among municipalities. Roe deer population growth rates were lower in the municipalities with lynx and harsh climatic conditions than in municipalities with mild climatic conditions and/or without lynx. Thus, lynx presence appears to be having a negat...

Management of large herbivores could be improved by investing less effort in estimating absolute abundance and more effort tracking variation over time of indicators of ecological change (IEC) describing animal performance, herbivore impact on habitat, and relative animal abundance. To describe relative changes in animal abundance, monitoring trends in numbers through indices may constitute a useful and low cost method, especially at large spatial scales. Reliability of indices to detect trends should be evaluated before they are used in wildlife management. We compared population trends estimated from spotlight counts, a standard census method for deer populations, with population size estimates of a red deer Cervus elaphus population monitored using Capture-Mark-Recapture (CMR) methodology. We found a strong negative effect of conditions of observation (e.g. rainfall) on both the number of animals (-24.4%) and the number of groups (-31.6%) seen per kilometre. After controlling for observation c...

An explanation for female multiple mating when males offer no material benefits but sperm remains elusive, largely because of a lack of empirical support for the genetic benefits hypothesis. We used 21 microsatellite markers to test for multiple paternities among 88 litters of roe deer, Capreolus capreolus, and to investigate the inbreeding avoidance hypothesis as a potential mechanism for the evolution of female multiple mating. From paternity analyses, we found that 13.5% of polytocous litters were sired by more than one male. We also found that a half-sib relationship was more likely than a full-sib relationship for 20.5% of all litters. This is the first report of multiple paternities in a territorial ungulate species. In support of the inbreeding avoidance hypothesis, we found that parents who were strongly related produced offspring with lower individual heterozygosity that survived less well during their first summer than fawns with unrelated parents. In addition, fawns from multiple paternity litters survived their first summer better than fawns from single paternity litters. However, it remains unclear whether all female multiple paternity events in this species are provoked by an initial consanguineous mating. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society 2009, 97, 128–139.

Although ground counts are often used to monitor ungulate populations, several studies show that counts of ungulates have low precision and often underestimate population size. We assessed the reliability of ibex Capra ibex counts as performed in French national parks, by analysing up to 23 years of annual censuses of six ibex populations for which a subset of animals were individually marked. We compared the population growth rate obtained from census data (estimated by use of four different methods) with the growth rate calculated from a demographic model including parameters estimated from capture-mark-recapture methods. The correlations between count-based estimates and growth rate obtained from demographic models were adequate to suggest that ground counts can monitor trends in population size of ibex, provided that the occasional undercounts are identified. Substantial undercounts in some years led to biologically impossible values of yearly population growth (λ>1.35) and, in the longest ti...

The wild boar (Sus scrofa) is a large, sexually dimorphic ungulate that exhibits a life-history tactic different from what would be predicted for a mammal of its size. In particular, litter size is larger and adult survival usually lower in wild boars than in other species of comparable size. We used capture–mark–recapture methods to model survival in a Mediterranean population (S. s. majori) of wild boars during an 8-year period, using a large sample of individually tagged animals of known age, to investigate demographic patterns and the effects of variable environmental conditions (e.g., summer droughts), which are believed to have a strong impact on the demography of this species. Contrary to the predictions based on our current knowledge of life-history theory, survival of wild boars differed less among age classes and between sexes than has been reported in other large mammals. As predicted from current theories on sexual selection, the impact of environmental factors was stronger on males than on females. This study documents for wild boars a life-history tactic different from the accepted model for large ungulates but similar to the tactic observed in small terrestrial mammals.

There is almost no information on age-specific survival of Asiatic ungulates based on mark-recapture studies. Survival of marked Punjab urial (Ovis vignei punjabiensis Lydekker, 1913) aged 0-2 years was studied in the Salt Range, Pakistan, in 2001-2005. Male lambs were heavier than females at birth. The relationship between litter size and birth mass varied among years, with a tendency for twins to be lighter than singletons. Birth mass had a positive but nonsignificant relation with survival to 1 year. Neither sex nor litter size affected survival to 1 year, which averaged 55% (95% CI = 41%-68%). There was no sex effect on survival of yearlings, which averaged 88% (95% CI = 4%-100%). Although sur- vival of lambs and yearlings was similar to that reported for other ungulates, apparent survival of 2- and 3-year-olds was very low at only 47%, possibly because of emigration. Early survival in this protected area is adequate to allow population growth, but more data are required on adult survival. Resume´ : En l'absence de suivis par capture-marquage-recapture, il n'y a pratiquement pas d'information disponible sur la variation des taux de survie en fonction de l'age pour les especes d'ongules asiatiques. Nous avons etudiela survie d'urials du Punjab (Ovis vignei punjabiensis Lydekker, 1913) individuellement marques entre 0 et 2 ans dans la region de la chaoˆne de Salt, au Pakistan, entre 2001 et 2005. Les agneaux males etaient plus lourds que les agnelles ala naissance. La relation entre la taille de la portee et la masse ala naissance variait entre les annees et les jumeaux montraient une tendance aetre plus legers. La masse a la naissance avait une influence positive mais non-significative sur la survie a `

Reproductive allocation at one age is predicted to reduce the probability of surviving to the next year or to lead to a decrease in future reproduction. This prediction assumes that reproduction involves fitness costs. However, few empirical studies have assessed whether such costs may vary with the age at primiparity or might be overridden by heterogeneities in individual quality. We used data from 35 years' monitoring of individually marked semi-domestic reindeer females to investigate fitness costs of reproduction. Using multi-state statistical models, we compared age-specific survival and reproduction among four reproductive states (never reproduced, experienced non-breeders, reproduced but did not wean offspring, and reproduced and weaned offspring) and among contrasted age at primiparity. We assessed whether reproductive costs occurred, resulting in a trade-off between current reproduction and future reproduction or survival, and whether early maturation was costly or rather reflected differences in individual quality of survival and reproduction capabilities. We did not find any evidence for fitness costs of reproduction in female reindeer. We found no cost of gestation and lactation in terms of future reproduction and survival. Conversely, successful breeders had higher survival and subsequent reproductive success than experienced non-breeders and unsuccessful breeders, independently of the age at primiparity. Moreover, it was beneficial to mature earlier, especially for females that successfully weaned their first offspring. Successful females at early primiparity remained successful throughout their life, clearly supporting the existence of marked among-female differences in quality. The weaning success peaked for multiparous females and was lower for first-time breeders, indicating a positive effect of experience on reproductive performance. Our findings emphasize an overwhelming importance of individual quality and experience to account for observed variation in survival and reproductive patterns of female reindeer that override trade-offs between current reproduction and future performance, at least in the absence of harsh winters.

Natal dispersal is a three-phase process: the decision to leave the natal range, the search phase and finally the settlement phase. Not much is known about the search phase in large herbivores. We quantified the search behaviour of young roe deer from two contrasting populations, using different measures: search area, search rate, search intensity and philopatry of the search. A Principal Component Analysis showed that most measures were highly correlated. Comparing the first axis from this analysis between adult and young roe deer from the two different populations while controlling for habitat quality, we found that the young occupied a larger area, ranged on average farther away and performed more excursions than adults, regardless of their sex. These findings support the hypothesis that young roe deer explore their environment before definitively leaving their natal home range and settling in their adult range.

The canalization hypothesis postulates that the rate at which trait variation generates variation in the average individual fitness in a population determines how buffered traits are against environmental and genetic factors. The ranking of a species on the slow-fast continuum - the covariation among life-history traits describing species-specific life cycles along a gradient going from a long life, slow maturity, and low annual reproductive output, to a short life, fast maturity, and high annual reproductive output - strongly correlates with the relative fitness impact of a given amount of variation in adult survival. Under the canalization hypothesis, long-lived species are thus expected to display less individual heterogeneity in survival at the onset of adulthood, when reproductive values peak, than short-lived species. We tested this life-history prediction by analysing long-term time series of individual-based data in nine species of birds and mammals using capture-recapture models. We found that individual heterogeneity in survival was higher in species with short-generation time (3 years) than in species with long generation time (4 years). Our findings provide the first piece of empirical evidence for the canalization hypothesis at the individual level from the wild.

The fitness costs of reproduction can be masked by individual differences, and may only become apparent during adverse environmental conditions. Individual differences, however, are usually assessed by reproductive success, so how fitness costs are influenced by the interplay between the environmental context and overall individual differences requires further investigation. Here, we evaluated fitness costs of reproduction based on 15 yr of monitoring of individual Alpine ibex (Capra ibex) during a period when the population was affected by a severe disease outbreak (pneumonia). We quantified fitness costs using a novel multi-event capture-mark-recapture (CMR) modeling approach that accounted for uncertainty in reproductive status to estimate the survival and reproductive success of female ibex while also accounting for overall individual heterogeneity using mixture models. Our results show that the ability of females to reproduce was highly heterogeneous. In particular, one group including 76% of females had a much higher probability of giving birth annually (between 0.66 and 0.77, depending on the previous reproductive status) than females of the second group (24% of females, between 0 and 0.05 probability of giving birth annually). Low reproductive costs in terms of future reproduction occurred and were independent of the pneumonia outbreak. There was no survival cost of reproduction either before or after the epizootic, but the cost was high during the epizootic. Our findings indicate that adverse environmental conditions, such as disease outbreaks, may lead to survival costs of reproduction in long-lived species and select against females that have a high reproductive effort. Thereby, the occurrence of adverse conditions increases the diversity of reproductive tactics within a population.

Environmental conditions experienced during early growth and development markedly shape phenotypic traits. Consequently, individuals of the same cohort may show similar life-history tactics throughout life. Conditions experienced later in life, however, could fine-tune these initial differences, either increasing (cumulative effect) or decreasing (compensatory effect) the magnitude of cohort variation with increasing age. Our novel comparative analysis that quantifies cohort variation in individual body size trajectories shows that initial cohort variation dissipates throughout life, and that lifetime patterns change both across species with different paces of life and between sexes. We used longitudinal data on body size (mostly assessed using mass) from 11 populations of large herbivores spread along the “slow-fast” continuum of life histories. We first quantified cohort variation using mixture models to identify clusters of cohorts with similar initial size. We identified clear cohort clusters in all species except the one with the slowest pace of life, revealing that variation in early size is structured among cohorts and highlighting typological differences among cohorts. Growth trajectories differed among cohort clusters, highlighting how early size is a fundamental determinant of lifetime growth patterns. In all species, among-cohort variation in size peaked at the start of life, then quickly decreased with age and stabilized around mid-life. Cohort variation was lower in species with a slower than a faster pace of life, and vanished at prime age in species with the slowest pace of life. After accounting for viability selection, compensatory/catch-up growth in early life explained much of the decrease in cohort variation. Females showed less phenotypic variability and stronger compensatory/catch-up growth than males early in life, whereas males showed more progressive changes throughout life. These results confirm that stronger selective pressures for rapid growth make males more vulnerable to poor environmental conditions early in life and less able to recover after a poor start. Our comparative analysis illustrates how variability in growth changes over time in closely related species that span a wide range on the “slow-fast” continuum, the main axis of variation in life-history strategies of vertebrates. This article is protected by copyright. All rights reserved.

The diversity of traits across species is organized around main axes of variation in life history. Among them, the slow–fast continuum first described by Stearns (1983) is the most frequently analyzed. After presenting the history of this slow–fast continuum, we perform an updated review of its empirical support from analyses of vertebrates. We show that conflicting results and interpretation reported in previous studies can be attributed to various problems, including the lack of consideration of dimension as the most crucial issue. When these problems are solved, in particular by doing a principal component analysis using only traits measured in units of time, the slow–fast continuum is the main axis of variation in life history across vertebrate species. Species range from a fast end with short developmental time, early reproduction, frequent reproductive attempts, and short lifespan to a slow end with long developmental time, delayed reproduction, spaced out reproductive attempts, and long lifespan. All these traits have similar loadings on the slow–fast continuum, supporting the concept of physiological time. We then discuss the possible existence of other axes of life history variation and identify some lines for future research.

1. Despite the observed distribution of variable individual phenotypes, survival and reproductive performance in wild populations, models of population dynamics often focus on mean demographic rates. Populations are constituted by individuals with different phenotypes and thus different performance. However, many models of population dynamics provide no understanding of the influence of this phenotypic variation on population dynamics. 2. In this paper, we investigate how the relationships between demographic rates and phenotype distribution influence the transmission and the upholding of phenotypic variation, and population dynamics. We used integral projection models to measure associations between differences of phenotypic trait (size or mass) among individuals and demographic rates, growth and inheritance, and then quantify the influence of phenotypic variation on population dynamics. We build an analytical and general model resulting from simplifications assuming small phenotypic variance. We illustrate our model with two case studies: a short and a long-lived life-history. 3. Population growth rate r is determined by a Lotka-style equation in which survival and fertility are averaged over a phenotypic distribution that changes with age. Here, we further decomposed r to show how much it is affected by shifts in phenotypic average as well as variance. We derived the elasticities of r to the first and second derivative of each demographic rate. In particular, we show that the nonlinearity of change in selective pressure with phenotype matters more to population dynamics than the strength of this selection. In others words, the variance of a given trait will be most important when the strength of selection increases (or decreases) nonlinearly with that trait. 4. Inheritance shapes the distribution of newborn phenotype. Even if newborns have a fixed average phenotype, the variance among newborns increases with phenotypic variance among mothers, strength of inheritance, and developmental variation. We explain how the components of inheritance can influence phenotypic variance and thus the demographic rates and population dynamics. In particular, when mothers of different ages produce offspring of different mean phenotype, the inheritance function can have a large influence on both the mean and variance of the trait at different ages and thus on the population growth rate. 5. We provide new tools to understand how phenotypic variation influence population dynamics and discuss in which life-histories we expect this influence to be large. For instance, in our short-lived life-history, individual variability has larger effect than in our long-lived life-history. We conclude by indicating future directions of analysis.

Selective harvest may lead to rapid evolutionary change. For large herbivores, trophy hunting removes males with large horns. That artificial selection, operating in opposition to sexual selection, can lead to undesirable consequences for management and conservation. There have been no comparisons of long-term changes in trophy size under contrasting harvest pressures. We analyzed horn measurements of Stone's rams (Ovis dalli stonei) harvested over 37 years in two large regions of British Columbia, Canada, with marked differences in hunting pressure to identify when selective hunting may cause a long-term decrease in horn growth. Under strong selective harvest, horn growth early in life and the number of males harvested declined by 12% and 45%, respectively, over the study period. Horn shape also changed over time: horn length became shorter for a given base circumference, likely because horn base is not a direct target of hunter selection. In contrast, under relatively lower hunting pressure, there were no detectable temporal trends in early horn growth, number of males harvested, or horn length relative to base circumference. Trophy hunting is an important recreational activity and can generate substantial revenues for conservation. By providing a reproductive advantage to males with smaller horns and reducing the availability of desirable trophies, however, excessive harvest may have the undesirable long-term consequences of reducing both the harvest and the horn size of rams. These consequences can be avoided by limiting offtake.

Immune gene variability influences roe deer natal dispersal

Additional file 2. Model selection procedure. This additional file describes in detail the procedure to select the best model describing contact detection success rate, false negative rate and contact-triggered GPS location success rate).

Summary 1. Animal space use has been studied by focusing either on geographic (e.g. home ranges, species’ distribution) or on environmental (e.g. habitat use and selection) space. However, all patterns of space use emerge from individual movements, which are the primary means by which animals change their environment. 2. Individuals increase their use of a given area by adjusting two key movement components: the duration of their visit and/or the frequency of revisits. Thus, in spatially heterogeneous environments, animals exploit known, high-quality resource areas by increasing their residence time (RT) in and/or decreasing their time to return (TtoR) to these areas. We expected that spatial variation in these two movement properties should lead to observed patterns of space use in both geographic and environmental spaces. We derived a set of nine predictions linking spatial distribution of movement properties to emerging space-use patterns. We predicted that, at a given scale, high variation in RT and TtoR among habitats leads to strong habitat selection and that long RT and short TtoR result in a small home range size. 3. We tested these predictions using moose (Alces alces) GPS tracking data. We first modelled the relationship between landscape characteristics and movement properties. Then, we investigated how the spatial distribution of predicted movement properties (i.e. spatial autocorrelation, mean, and variance of RT and TtoR) influences home range size and hierarchical habitat selection. 4. In landscapes with high spatial autocorrelation of RT and TtoR, a high variation in both RT and TtoR occurred in home ranges. As expected, home range location was highly selective in such landscapes (i.e. second-order habitat selection); RT was higher and TtoR lower within the selected home range than outside, and moose home ranges were small. Within home ranges, a higher variation in both RT and TtoR was associated with higher selectivity among habitat types (i.e. third-order habitat selection). 5. Our findings show how patterns of geographic and environmental space use correspond to the two sides of a coin, linked by movement responses of individuals to environmental heterogeneity. By demonstrating the potential to assess the consequences of altering RT or TtoR (e.g. through human disturbance or climatic changes) on home range size and habitat selection, our work sets the basis for new theoretical and methodological advances in movement ecology.

The purpose of this text is to provide a broad overview of wildlife demography and explain how demographic approaches shed light on wildlife conservation and management issues. First, we summarize the main interactions between humans and wildlife and briefly review the history of research on wildlife demography and modern tools for wildlife demography. In a comparative perspective, we then show how the diversity of wildlife life cycles and demography is organized on a slow-fast continuum and how the theory of exploited populations can be used to understand different sensitivities to extra sources of mortality along this continuum. We then present some key aspects of variation in demographic parameters such as environmental variation and density-dependence. In a general discussion we will briefly present what we think are the dominant trends for future research on wildlife demography.

Data on the age, sex and condition of roe deer Capreolus capreolus killed by Eurasian lynx Lynx lynx and human hunters were collected in two study areas in the counties of Nord-Trondelag and Hedmark in central and southeastern Norway, respectively. Data on the age and sex structure of the standing population were also collected. No differences in the age or sex structure of roe deer killed by lynx were found between the two study areas or between years with differing snow depths which was expected to affect age-class vulnerability. The profile of 151 lynx-killed roe deer (24% adult males, 44% adult females, 11% male fawns and 21% female fawns) was not statistically different from that of the standing population. In contrast, hunters killed a significantly larger proportion of adult animals, especially males (44% adult males, 28% adult females, 15% male fawns and 13% female fawns). The detailed age structure of lynx killed and hunter killed animals was not different within the adult age class. The...

1. High-density populations of large herbivores are now widespread. Wildlife managers commonly attempt to control large herbivores through hunting to meet specific management objectives, considering population density as the minimal key source of information. Here, we review the problems of censusing populations of large herbivores and describe an alternative approach, employing indicators of ecological change. 2. Estimating density of large herbivores with high precision and accuracy is difficult, especially over large areas, and requires considerable investment of time, people and money. Management decisions are often made on an annual basis, informed by population changes over the previous year. However, estimating year-to-year changes in density is not a realistic goal for most large herbivores. Furthermore, population density per se provides no information on the relationship between the population and its habitat. 3. For successful management of large herbivores, we need to consider not only the fate of the population, but rather changes in both population and habitat features, as well as their interaction. Managers require information on trends in both the animal population and habitat quality in order to interpret changes in the interaction between these two compartments. 4. We propose that a set of indicators of animal performance, population abundance, habitat quality and/or herbivore habitat impact provides relevant information on the population– habitat system. Monitoring temporal changes in these indicators provides a new basis for setting hunting quotas to achieve specific management objectives. This sort of adaptive management is employed widely in France for managing roe deer Capreolus capreolus . 5. Synthesis and applications . The management of large herbivores would be improved by investing fewer resources in trying to estimate the absolute abundance of ungulates, and more resources in collecting additional data to inform understanding of the ecological status of the ungulate–habitat system being managed. This paper presents a set of indicators of ecological change for monitoring the interaction between a population and its habitat as a basis for adaptive management to attain explicit goals and to improve knowledge of the system. This approach could improve management for a variety of large herbivores, by harmonizing actions at wide spatial scales.

1) Micro-evolutionary predictions are complicated by ecological feedbacks like density dependence, while ecological predictions can be complicated by evolutionary change. A widely used approach in micro-evolution, quantitative genetics, struggles to incorporate ecological processes into predictive models, while structured population modelling, a tool widely used in ecology, rarely incorporates evolution explicitly. 2) In this paper we develop a flexible, general framework that links quantitative genetics and structured population models. We use the quantitative genetic approach to write down the phenotype as an additive map. We then construct integral projection models for each component of the phenotype. The dynamics of the distribution of the phenotype are generated by combining distributions of each of its components. Population projection models can be formulated on per generation or on shorter time steps. 3) We introduce the framework before developing example models with parameters chosen to exhibit specific dynamics. These models reveal (i) how evolution of a phenotype can cause populations to move from one dynamical regime to another (e.g. from stationarity to cycles), (ii) how additive genetic variances and covariances (the G matrix) are expected to evolve over multiple generations, (iii) how changing heritability with age can maintain additive genetic variation in the face of selection and (iii) life history, population dynamics, phenotypic characters and parameters in ecological models will change as adaptation occurs. 4) Our approach unifies population ecology and evolutionary biology providing a framework allowing a very wide range of questions to be addressed. The next step is to apply the approach to a variety of laboratory and field systems. Once this is done we will have a much deeper understanding of eco-evolutionary dynamics and feedbacks., 41 pages, 5 figures