Diseases and reproductive success in a wild mammal: example in the alpine chamois

Density-dependent and climatic factors affect reproduction and dynamics of wild ungulates. Parasites can also decrease reproductive success through either a direct abortive effect or a negative impact on host growth and body condition. However, few studies have investigated the effect of parasitism on fecundity of ungulates in natural conditions. We studied three bacterial infections caused by Salmonella enterica serovar Abortusovis, Chlamydophila abortus and Coxiella burnetii. These bacteria are leading causes of reproductive failure in sheep, goat and cattle, which raises the question of their influence on population dynamics of wild ungulates. A long-term study of demography and epidemiology of an alpine chamois (Rupicapra rupicapra, L.) population (Les Bauges Reserve, France) and a generalized linear modeling approach were used to analyze the reproductive success of chamois according to population density, weather conditions and the prevalence of antibodies against the three bacteria in females. This approach enabled us to identify the confounding effect of weather and parasitism on fecundity in a natural population. After accounting for density, the prevalence of antibodies against the three bacteria explained 36% of the annual variation in reproductive success, and weather conditions explained an additional 31%. This study was, to our knowledge, the first to compare the decrease in fecundity due to bacterial infections and weather conditions in a population of wild mountain ungulates.     

Disentangling Natural From Hunting Mortality in an Intensively Hunted Wild Boar Population

Abstract We assessed age-specific natural mortality (i.e., excluding hunting mortality) and hunting mortality of 1,175 male and 1,076 female wild boar (Sus scrofa) from Chǎteauvillain-Arc en Barrois (eastern France), using a 22-year dataset (1982–2004) and mark-recapture-recovery methods. Overall yearly mortality was >50% for all sex and age-classes. Low survival was mostly due to high hunting mortality; a wild boar had a >40% of chance of being harvested annually, and this risk was as high as 70% for adult males. Natural mortality rates of wild boar were similar for males and females (approx. 0.15). These rates were comparable to rates typical of male ungulates but high for female ungulates. Wild boar survival did not vary across sex and age-classes. Despite high hunting mortality, we did not detect evidence of compensatory mortality. Whereas natural mortality for males was constant over time, female mortality varied annually, independent of fluctuations in mast availability. Female wild boar survival patterns differed from those reported in other ungulates, with high and variable natural mortality. In other ungulates, natural mortality is typically low and stable across a wide range of environmental conditions. These differences may partly reflect high litter sizes for wild boar, which carries high energetic costs. High hunting mortality may induce a high investment of females in reproduction early in life, at the detriment to survival. Despite high hunting mortality, the study population increased. Effective population control of wild boar should target a high harvest rate of piglets and reproductive females.     

Poor horse traders: large mammals trade survival for reproduction during the process of feralization

We investigated density dependence on the demographic parameters of a population of Camargue horses (Equus caballus), individually monitored and unmanaged for eight years. We also analysed the contributions of individual demographic parameters to changes in the population growth rates. The decrease in resources caused a loss of body condition. Adult male survival was not affected, but the survival of foals and adult females decreased with increasing density. Prime-aged females maintained high reproductive performance at high density, and their survival decreased. The higher survival of adult males compared with females at high density presumably results from higher investment in reproduction by mares. The high fecundity in prime-aged females, even when at high density, may result from artificial selection for high reproductive performance, which is known to have occurred in all the major domestic ungulates. Other studies suggest that feral ungulates including cattle and sheep, as these horses, respond differently from wild ungulates to increases in density, by trading adult survival for reproduction. As a consequence, populations of feral animals should oscillate more strongly than their wild counterparts, since they should be both more invasive (as they breed faster), and more sensitive to harsh environmental conditions (as the population growth rate of long-lived species is consistently more sensitive to a given proportional change in adult survival than to the same change in any other vital rate). If this principle proves to be general, it has important implications for management of populations of feral ungulates.     

Comparative survey of canine parvovirus,canine distemper virus and canine enteric coronavirus infection in free-ranging wolves of central Italy and south-eastern France

Diseases likely affect large carnivore demography and can hinder conservation efforts. We considered three highly contagious viruses that infect a wide range of domestic and wild mammals: canine parvovirus type 2 (CPV-2), canine distemper virus (CDV) and canine enteric coronaviruses (CECoV). Infection by either one of these viruses can affect populations through increased mortality and/or decreased general health. We investigated infection in the wolf populations of Abruzzo, Lazio e Molise National Park (PNALM), Italy, and of Mercantour National Park (PNM), France. Faecal samples were collected during one winter, from October to March, from four packs in PNALM (n?=?79) and from four packs in PNM (n?=?66). We screened samples for specific sequences of viral nucleic acids. To our knowledge, our study is the first documented report of CECoV infection in wolves outside Alaska, and of the large-scale occurrence of CPV-2 in European wolf populations. The results suggest that CPV-2 is enzootic in the population of PNALM, but not in PNM and that CECoV is episodic in both areas. We did not detect CDV. Our findings suggest that density and spatial distribution of susceptible hosts, in particular free-ranging dogs, can be important factors influencing infections in wolves. This comparative study is an important step in evaluating the nature of possible disease threats in the studied wolf populations. Recent emergence of new viral strains in Europe additionally strengthens the need for proactive monitoring of wolves and other susceptible sympatric species for viral threats and other impairing infections.     

Influence of Density and Climate on Population Dynamics of a Large Herbivore Under Harsh Environmental Conditions

ABSTRACT Dynamics of herbivore populations can be influenced both by density-dependent processes and climate. We used age-at-harvest data for adult female white-tailed deer (Odocoileus virginianus) collected over 23 years to estimate survival and reproduction by age class and to identify effects of environmental factors. The study population was located on Anticosti Island (QC, Canada), at the northern limit of the species' range; the population was at high density, and the landscape had scarce forage and abundant snow during winter. Despite severe environmental conditions, population growth apparently increased during the study; adult survival was similar to other populations, although reproduction appeared lower. Winter severity was not related to survival, but density affected adult female survival. Density at estrus was the main factor influencing reproduction of 2- and 3–4-year-olds and also affected reproduction of prime-aged females (5–9-yr-olds), but not of older females. Reproductive rate of younger females was influenced by environmental conditions in autumn, such as high density or snow conditions that limited forage availability. Reproductive success of 5–9- and ≥10-year-old females appeared dependent on spring conditions favoring high-quality forage, probably through effects on neonatal survival. Relative to other studies on northern ungulates, demographic processes in our study appeared to be more affected by autumn and spring climate, in addition to population density, than by winter climate. We thus propose that population density, as well as autumn and spring climate, should be considered in management strategies. Harvest data offered a unique opportunity to study forest ungulates, for which individual monitoring is rarely possible.     

Factors influencing home range and activity of wild boar (Sus scrofa) in a Mediterranean coastal area

This paper analyses the temporal variation in the size of home range and activity of adult wild boar ( Sus scrofa L.). Eighteen boar were radiotracked between 1991 and 1993 in the Maremma Natural Park (Central Italy). Variations of home-range size and activity were related to sex, winter food availability and population density. The hypotheses that home-range size was inversely related to food availability and population density, and that the amount of activity was directly related to population density and inversely related to food abundance, were tested. The size of the acorn crop was used as a measure of winter resource level. No differences were found in the size of ranges, core area, and activity between males and females. In 1991–92 home-range size was larger than in 1992–93; conversely, activity increased from 1991–92 to 1992–93. Winter food availability was high in 1991–92 and low in the following year. Population density increased greatly in spring 1992 but crashed in spring and summer 1993, when a high mortality of wild boar occurred due to starvation.
The decrease in home-range size during the food shortage was explained as a possible strategy adopted by wild boar to cope with starvation. The difference in home-range size and amount of activity found between the first and the second year of study were probably influenced by differences in population density, although the individual effects of food availability and population density were not clearly separable.     

Dung avoidance as a possible mechanism in competition between wild and domestic ungulates: two experiments with chamois <Emphasis Type="Italic">Rupicapra rupicapra</Emphasis>

Wild ungulates often adjust spatial behaviour where they coexist with livestock. In European mountains, chamois Rupicapra rupicapra or R. pyrenaica commonly avoid alpine pastures used by domestic sheep. Mechanisms leading to competitive losing out of the wild species are not well understood, but mostly, resource competition is inferred and sometimes demonstrated. We hypothesised that chamois need to minimise the risk of intestinal parasite uptake and therefore would avoid pastures contaminated with sheep dung. We tested this in two experiments by contaminating feeding patches of wild and captive chamois with (parasite-free) sheep faeces. Wild chamois did not avoid grazing sites or plots on which sheep dung had been placed at a (low) density representing the commonly encountered situation in the Swiss Alps. Captive chamois strongly reduced browsing time on small trees given for food when the surroundings of the trees were sprayed with a watery faecal solution. We concluded that the odour signalled a potential high risk of parasite infection to the captive chamois, whereas the density of sheep dung on the grazing site of wild chamois was not high enough to be perceived as a risk. The need to minimise endoparasite uptake from faeces may therefore play a role in driving spatial behaviour of wild ungulates and could result in competitive imbalance between wild and domestic ungulates.     

Comparative evaluation of effort, capture and handling effects of drive nets to capture roe deer (Capreolus capreolus), Southern chamois (Rupicapra pyrenaica) and Spanish ibex (Capra pyrenaica)

The objective of this study is to assess the usefulness of drive nets to capture roe deer (Capreolus capreolus), Southern chamois (Rupicapra pyrenaica) and Spanish ibex (Capra pyrenaica), comparing the results obtained with other capture methods and amongst the three species. Sixty-five drive net capture operations using beaters were conducted from January 1998 to September 2004. A total of 161 wild ungulates (31 roe deer, 95 Southern chamois and 35 Spanish ibexes) were captured. The average number of animals captured per operation was 1.07 for roe deer, 3.96 for Southern chamois and 2.92 for Spanish ibex. The average number of person–days per captured animal was 21.5, 7.1 and 10.6 for roe deer, Southern chamois and Spanish ibex, respectively. Specificity was 100% for Southern chamois and Spanish ibex (only the target species captured) and 77.5% for roe deer. Risk for the animals (mortality plus injuries) was 3.23% for roe deer, 5.27% for Southern chamois and 0% for Spanish ibex, whereas injuries to the operators occurred with 3.1% of the handled animals. Sex ratio was skewed towards females in roe deer, towards males in Southern chamois and balanced in Southern chamois. Drive nets showed good performance, although many operators were required. Safety for the animals and specificity were higher than traditionally attributed to this capture method. It is concluded that drive nets are an efficient and safe method to capture many ungulate species.     

Unbiased sex-specific survival in Alpine chamois

Many polygynous ungulates show higher mortality of males than of females, because of the intense male–male competition during the rut and the costs associated with the development of sexual-size dimorphism. In the weakly dimorphic Alpine chamois Rupicapra rupicapra the occurrence of differential sex-specific survival strategies is controversial. To date, only two studies investigated the survivorship of males and females in this species, producing conflicting results: these works, based on the use of life tables, require confirmation from researches carried out on living populations. We assessed the survival pattern of a protected Alpine chamois population in the Swiss National Park, where 116 individuals were marked and monitored over 13 years (1996–2008). We tested for sex-, age- and year-dependence of survival by means of capture-mark-resight models. Resighting probabilities were sex-dependent, and survival rates were time-dependent. Females had higher resighting probabilities (0.84) than males (0.74). All over the time periods, sex had a weak influence on survival probability (males = 0.91; females = 0.92) and survival rates remained surprisingly high until late age (1 year = 0.90; 2–7 years = 0.91; 8+ years = 0.92). The growing evidence for a high adult survival and a weak differential mortality of the two sexes, together with the highly seasonal sexual-size dimorphism observed for Alpine chamois, might indicate the occurrence of a unique conservative survival strategy in both sexes and a low-risk mating strategy by males.     

Density dependence in a fluctuating wild reindeer herd; maternal vs. offspring effects

Summary The Hardangervidda wild reindeer herd in Norway is the largest in Western Europe. It has fluctuated between 7000 and 32000 animals during the last 35 years. Four density-dependent effects were found: 1. A food limitation effect due to a shift in diet after overgrazing lichen on the winter range. This led to increased tooth wear and lowered body size and fat reserves. 2. A significant correlation between population density and juvenile winter survival rate. No effect on adult female survival rate was found. 3. A cohort effect. After population increase and overgrazing, recruitment was reduced by 30% and remained so after population reduction. Birth weights had increased by 30% 5 years after population reduction and the mean calving time was earlier. As a result, after population reduction weights of newborns were 40% greater at a comparable date. Neonatal survival rate was related to maternal condition during the last part of gestation which coincides with the peak winter snow accumulation. The slow increase in adult dressed body weights (DBW) after population reduction is due to the combined effects of increased tooth wear when winter range was limiting and to the cohort-generation time, so that an improvement in neonatal survival and size was first expressed in subsequent offspring cohorts. 4. An inter-generation effect. During 30 years of resource limitation, DBW decreased by 23%, birth rate was unchanged after the first peak, while fecundity increased by 15%, suggesting increased reproductive effort per unit body weight. Natural selection for increased reproductive effort by smaller females when food was limiting was suggested. Some size-effect due to hunters selecting the largest adult phenotypes was possible but not the main cause. These results do not support some earlier hypotheses about the effects of population density on size at maturity in ungulates.     

Pasture Quality Affects Juvenile Survival through Reduced Maternal Care in a Mountain‐Dwelling Ungulate

Lactation exerts heavy energetic and physiological costs to mothers, whilst determining early growth and survival of offspring. To mountain ungulates, access to high‐quality forage during nursing and weaning is crucial for reproductive success. We have evaluated the effects of pasture quality on suckling behaviour and winter survival of Apennine chamois Rupicapra pyrenaica ornata kids, across three areas. Areas A‐B (‘poor’ areas) were characterised by a reduced availability of nutritious forage, thus a lower diet quality for female chamois and kids; Area C (a ‘rich’ area) included a much greater availability of nutritious forage. In poor areas, pasture quality has been reduced by climatic and plant composition changes, as well as the presence of a herbivore competitor (red deer Cervus elaphus). In poor areas, we recorded a significantly (1) lower suckling success of chamois kids (number of suckling bouts/number of suck attempts); (2) lower frequency of suckling bouts (n. suckling bouts/kid/h); and (3) lower suckling intensity (suck duration/kid/h) in respect to the rich area. Conversely, frequencies of suckling rejections and those of suckling attempts (n. events/kid/h) were the lowest in the rich area. Winter survival of chamois kids was c. 2 times greater in the rich area (45%) than in poor areas (20–26%). In the poor areas, resource scarcity induced adult female chamois to decrease maternal cares and favour their own maintenance, ultimately affecting population dynamics through kid winter mortality.     

Disentangling demographic effects of red deer on chamois population dynamics

Investigating the impact of ecological factors on sex‐ and age‐specific vital rates is essential to understand animal population dynamics and detect the potential for interactions between sympatric species. We used block count data and autoregressive linear models to investigate variation in birth rate, kid survival, female survival, and male survival in a population of Alpine chamois Rupicapra rupicapra rupicapra monitored over 27 years within the Stelvio National Park, Central Italian Alps, as function of climatic variables, density dependence, and interspecific competition with red deer Cervus elaphus. We also used path analysis to assess the indirect effect of deer abundance on chamois growth rate mediated by each demographic parameter. Based on previous findings, we predicted that birth rate at [t] would negatively relate to red deer abundance at year [t − 1]; survival rates between [t] and [t + 1] would negatively relate to red deer abundance at year [t − 1] and to the interactive effect of winter precipitation at [t + 1] and chamois density at [t]. Our results showed that birth rate was positively related to spring–summer precipitation in the previous year, but this effect was hampered by increasing red deer abundance. Kid and female survival rates were negatively related to the combined effect of chamois abundance and winter precipitation. Male and female survival rates were negatively related to lagged red deer abundance. The path analysis supported a negative indirect effect of red deer abundance on chamois growth rate mediated by birth rate and female survival. Our results suggest that chamois population dynamics was largely explained by the synergistic effect of density dependence and winter harshness, as well as by interspecific competition with red deer, whose effects were seemingly stronger on the kid–female segment of the population.     

Influence of weather and phenotypic characteristics on pregnancy rates of female roe deer in central Italy

In many ungulates, female fecundity is influenced by weather, population density and body condition. Based on a six-year survey of the reproductive tracts of adult female roe deer (Capreolus capreolus) harvested in the province of Pisa (Tuscany, central Italy), we evaluated the influence of weather, population density and individual characteristics on pregnancy rates. Eighty-five percent of females were pregnant, with a median litter size of two (range one—three). We found that pregnancy rate was positively correlated with summer rainfall and body mass of females, whereas early-winter conditions, spring rainfall, the age of females and density-dependent factors did not appear to influence pregnancy rate. These results reflect the particular seasonal variation in the abundance and quality of resources in Mediterranean habitats and show that heavier females (high-quality mothers) are more productive than lighter females.     

Contributions of forage competition, harvest, and climate fluctuation to changes in population growth of northern white-tailed deer

Recently there has been considerable interest in determining the relative roles of endogenous (density-dependent) and exogenous (density-independent) factors in driving the population dynamics of free-ranging ungulates. We used time-series analysis to estimate the relative contributions of density-dependent forage competition, climatic fluctuation, and harvesting on the population dynamics of white-tailed deer (Odocoileus virginianus) in Nova Scotia, Canada, from 1983 to 2000. A model incorporating the population density 2 years previous, an interaction term for the harvest of females and population density 2 years previous, and the total snowfall during the previous 2 winters explained 80% of the variation in inter-annual population growth rate. Natality of adult females was negatively related to deer density during the present winter, whereas that of yearlings may have been correlated with the snowfall of three winters previous. Natality of fawns was related to deer density and total snowfall during the previous winter. Coyotes (Canis latrans) prey extensively on deer fawns in northeastern North America and the annual harvest of snowshoe hares (Lepus americanus), the major alternate prey of coyotes, explained 48% of the inter-annual variation in fawn recruitment. The proportions of fawn, yearling, and adult deer suffering from severe malnutrition during late winter were all correlated with deer density during the present winter. We conclude that the limiting effects of winter weather on over-winter survival of deer may be cumulative over two consecutive winters. During the late 1980s, density dependence and winter severity acted in concert to effect substantial declines in deer population growth both by effecting winter losses directly and by exacerbating predation by coyotes. During this period liberal harvesting did not relieve density-dependent forage competition and probably accelerated the decline.     

Wolf predation and snow cover as mortality factors in the ungulate community of the Bialowieża National Park,Poland

Summary Wolf-ungulate interactions were studied in the pristine deciduous and mixed forests of the Bialowiea National Park in 1985–1989. The study period included two severe and two mild winters. The community of ungulates inhabiting Bialowiea National Park consisted of red deer Cervus elaphus, 55% of all ungulates; wild boar Sus scrofa, 42%; and roe deer Capreolus capreolus, moose Alces alces, and European bison Bison bonasus, about 1% each. The average size of red deer groups increased from 2.7 (SD 2.35) in spring and summer to 6.9 (SD 6.84) in autumn and winter. In winter the group size of red deer was positively correlated with the depth of snow cover and negatively correlated with the mean daily temperature. Average group size of wild boar did not change significantly between seasons; it was 6.8 (SD 5.16) in spring and summer and 5.7 (SD 4.67) in autumn and winter. Analysis of 144 wolf scats showed that wolves preyed selectively on red deer. In October–April, Cervidae (mostly red deer) constituted 91% of biomass consumed by wolves, while wild boar made up only 8%. In May–September deer formed 77% of prey biomass, and the share of wild boar increased to 22%. In all seasons of the year wolves selected juveniles from deer and boar populations: 61% of red deer and 94% of wild boar of determined age recovered from wolves' scats were young <1 year old. Analysis of 117 carcasses of ungulates found in Bialowiea National Park showed that predation was the predominant mortality factor for red deer (40 killed, 10 dead from causes other than predation) and roe deer (4 killed, none dead). Wild boar suffered most from severe winter conditions (8 killed, 56 dead). The percentage of ungulates that had died from undernutrition and starvation in the total mortality was proportional to the severity of winter.     

Linking alternative reproductive tactics and habitat selection in Northern chamois

In polygynous ungulates, males may achieve fertilization through the use of alternative reproductive tactics (ARTs), discrete phenotypic variations evolved to maximize fitness. ARTs are often associated with different male spatial strategies during the rut, from territoriality to female‐following. Although variation in space use patterns of rutting male ungulates is known to be largely affected by the spatial distribution of females, information on the year‐round habitat selection of alternative reproductive types is scant. Here, we investigate the seasonal variation in habitat choice of a large mammal with ARTs (territoriality and nonterritoriality), the Northern chamois Rupicapra rupicapra. Global Positioning System (GPS) data on 28 adult males were collected between February 2010 and December 2013 in the Gran Paradiso National Park (Italy) and used to fit resource selection functions to explore the ART‐specific use of key topographic features, such as elevation, aspect, and slope, and vegetation phenology expressed as NDVI values. Territorial and nonterritorial chamois profoundly differed in their habitat selection not only during the rutting season. Compared to nonterritorial males, territorial males used lower elevations in summer and autumn, preferred southern slopes in spring and summer, and used steeper areas in summer but not in winter. We found no difference in seasonal selection of NDVI values between males adopting ARTs. Our results suggest that territorial males tend to occupy warmer, lower‐food‐quality habitats in late spring and summer, whereas nonterritorial males are free to follow and exploit vegetation phenology and more favorable temperatures. Different patterns of habitat selection may reflect different trade‐offs between the optimization of energy balances throughout the year and the increase of mating opportunities during the rut in males adopting alternative reproductive tactics.     

Survey of Pestivirus infection in wild and domestic ungulates from south-western Italian Alps

The transmission of pestiviruses between domestic and wild ruminants has not been documented in communal alpine pastures shared between wildlife and livestock. The aim of this study was to investigate the role of domestic and wild ungulates species from Varaita Valley (SW Italian Alps) in the epidemiology of Pestivirus infections. Sera from free-ranging alpine chamois (Rupicapra rupicapra) and roe deer (Capreolus capreolus) were collected from 1994 to 2009 and 2001 to 2009, respectively. Also, sera from cattle and sheep sampled in 2009 were studied. Sera were tested for the presence of antibodies against pestivirus with an ELISA assay. Sera from positive animals were subsequently tested with a comparative virus neutralisation test using the BVDV-NADL and BDV-137/4 strains. Sera were tested for the presence of pestiviral antigen and the presence of viral RNA with a commercial ELISA assay and RT-PCR. Antibodies against Pestivirus were detected in 132 out of 312 (42%) chamois, in 30 out of 175 (17%) cattle and 6 out of 24 (25%) sheep. No antibodies were found in roe deer. No Pestivirus antigen or RNA was detected in any of the samples. Results indicate circulation of pestiviruses among the studied chamois, cattle and sheep populations. However the role of wild ungulates in the dynamics of Pestivirus infection is still unknown and monitoring the presence of these viruses in wild ungulates would be of importance, especially in the chamois population, where pestiviruses seem to circulate extensively.     

Reflections of ecological differences? Stress responses of sympatric Alpine chamois and red deer to weather,forage quality,and human disturbance

Depending on the habitats they live in, temperate ungulates have adapted to different degrees to seasonally changing forage and weather conditions, and to specific escape strategies from predators. Alpine chamois, a mountain ungulate, and red deer, originally adapted to open plains, would therefore be expected to differ in their physiological responses to potential stressors. Based on 742 chamois and 1557 red deer fecal samples collected year‐round every 2 weeks for 4 years at the same locations within a strictly protected area in the Swiss Alps, we analyzed glucocorticoid metabolite (FGM) concentrations for both species. Results from linear mixed effects models revealed no physiological stress response to changing visitor numbers, but instead to drought conditions for both species during summer. In winter, FGM concentrations increased with increasing snow height in both species, but this response was modulated by temperature in red deer. Chamois showed a stronger stress response to increasing snow height during November and December than between January and March, while FGM concentrations increased with decreasing temperature throughout winter. An increase in FGM concentrations with decreasing forage digestibility during winter was found only for red deer. The results are thus partly in contradiction to expectations based on feeding type and adaptations to different habitats between the two species. The lack of a response to forage digestibility in chamois may reflect either better adaptation to difficult feeding conditions in subalpine forests, or, by contrast, strong constraints imposed by forage quality. The similar responses of both species to weather conditions in winter suggest that climatic factors at the elevations examined here are sufficiently harsh to be limiting to temperate ungulates regardless of their specific adaptations to this environment.     

Male Alpine Chamois Occupy Territories at Hotspots Before the Mating Season

Ungulate mating systems vary broadly both between and within species. Studies on mating systems in different habitats can provide clues to the ecological factors determining this diversity. Despite its abundance in the European Alps and its importance as a game species, surprisingly little is known about the mating system of Alpine chamois Rupicapra rupicapra rupicapra. We tested the hypothesis that adult males first defend mating territories in late spring, when females segregate from males and well before the Nov. rut. In the Gran Paradiso National Park (north‐western Italian Alps), adult males shared a winter range but occupied individual ranges in summer and early autumn. Males were more aggressive to each other in the summer than in the spring. A strong site fidelity from one year to the next was found for the summer and early autumn months. Those males that occupied the same territories both in the summer and during the rut (Nov.) appeared to be at hotspots, attractive to females during the rut because of reduced snow cover. Other males appeared to cluster around these hotspots during the rut. Territories that were first occupied during the summer were visited by more females than those that were not established until the rut began. Our results suggest that the mating system of this population of Alpine chamois consists of the early occupation of clustered mating territories. The early establishment of mating territories in areas frequented by females during the rut may lead to reproductive benefits for male chamois.     

Population dynamics of large herbivores: variable recruitment with constant adult survival

Recent long-term studies of population ecology of large herbivorous mammals suggest that survival of prime-aged females varies little from year to year and across populations. Juvenile survival, on the other hand, varies considerably from year to year. The pattern of high and stable adult survival and variable juvenile survival is observed in contrasting environments, independently of the main proximal sources of mortality and regardless of whether mortality is stochastic or density-dependent. High yearly variability in juvenile survival may play a predominant role in population dynamics.