Alternative Mating Tactics and Their Impact on Survival in Adult Male Alpine Ibex (Capra ibex ibex)

Adult male Alpine ibex (Capra ibex ibex) have been shown to exhibit unusually high survival to relatively advanced ages (>10 years), leading to speculation that males may engage in an energetically conservative reproductive strategy that increases survival. We investigated the extent to which the adoption of alternative mating tactics contributes to the extraordinary survival of adult males in this species. Because basic information on the mating system of Alpine ibex is scarce, we 1st characterized the temporal and spatial distribution of receptive females. Our observations during 3 consecutive rutting seasons revealed 2 alternative mating tactics. Apparently dominant males monopolized individual receptive females by following and defending them, a tactic known as tending. In contrast, apparently subordinate males tried to achieve temporary access to tended females when the latter started to run, a tactic referred to as coursing. In total, 24 copulations were observed, of which 20 (83.3%) were the result of tending and 4 were the result of coursing. The adoption of the 2 tactics was strongly age-dependent; older males (9-12 years) engaged primarily in tending, whereas younger males (2-6 years) engaged mainly in coursing. Males adopting the coursing tactic spent more time in low-cost and less time in high-cost behaviors than males adopting the tending tactic. Time-budget comparisons with another ungulate species suggested that although tending is a relatively costly tactic, coursing is a low-cost tactic that may contribute to the exceptional adult survival in male Alpine ibe

Social dominance and conflict reduction in rutting male Alpine ibex, Capra ibex

In polygynous ungulates, male mortality is thought to be linked to high-energy expenditures during the rut. However, Alpine ibex (Capra ibex) adult males show an unusually high survival during this time. Male Alpine ibex live in social groups and thus, we assumed that they might reduce energy-intensive interactions during the rut by establishing, early on, strict dominance hierarchies. To evaluate this hypothesis, we studied social interactions and mating behavior in a population of Alpine ibex in the Swiss Alps. In accordance with our prediction, and in contrast to other polygynous ungulates, male Alpine ibex decreased time spent in agonistic interactions and the number of fights during the rut compared with the prerut, irrespective of their age. Changes between access-holding males always occurred without foregoing fights and were entirely based on preestablished and stable dominance relationships. Therefore, dominant males always gained and held access to receptive females and thus managed to adopt the tending tactic. Subordinate males either left the consort pair or they adopted the coursing tactic in order to achieve temporary access to estrous females. They behaved extremely reluctantly toward dominants, as they never made use of overt aggression to challenge them or to create actively transient mating opportunities. Our study supports the hypothesis that costly intramale interactions are reduced during the mating season in Alpine ibex by the adherence to preestablished and stable dominance relationships. Accordingly, male Alpine ibex appear to be able to cut down on energy expenditures, which in turn, likely contributes to their superior surviva

Climate effects on demographic parameters in an unhunted population of Alpine chamois (Rupicapra rupicapra)

Because of a rapidly changing climate, the need to understand how populations respond to varying climatic conditions has become increasingly important. Using long-term data from an unhunted population of Alpine chamois (Rupicapra rupicapra) and autoregressive time series models we investigated the extent to which the population demography was affected by local climate. Because density and weather are likely to operate differently on various sex—age categories, anticipated effects were assumed to vary among categories. Generally, elevated densities in 1 year negatively influenced the subsequent change in population size. Severe snow conditions during late winter negatively affected total population growth, and growth of the male, yearling, and juvenile segments of the population. A lagged effect of early winter snow on the change in animal numbers was demonstrated for females. Winter temperatures positively affected the growth rate of juveniles, whereas they appeared to have negative consequences for male and yearling growth rates. The juvenile-female ratio was negatively affected by the current female density, but did not respond to the various climate variables. Winter survival of juveniles was negatively influenced by the juvenile number during the preceding summer and harsh snow conditions during early winter. Our results indicate that winter climate shapes the demography of Alpine chamois. Particularly, winters with a lot of snow might have long-lasting consequences for the population. Considering the juveniles, lagged effects apparently operate through the body condition of their mothers. The conflicting effects of temperature on the different sex—age categories make the direction of expected population response to global warming difficult to predic

Male reproductive pattern in a polygynous ungulate with a slow life-history: the role of age, social status and alternative mating tactics

According to life-history theory age-dependent investments into reproduction are thought to co-vary with survival and growth of animals. In polygynous species, in which size is an important determinant of reproductive success, male reproduction via alternative mating tactics at young age are consequently expected to be the less frequent in species with higher survival. We tested this hypothesis in male Alpine ibex (Capra ibex), a highly sexually dimorphic mountain ungulate whose males have been reported to exhibit extremely high adult survival rates. Using data from two offspring cohorts in a population in the Swiss Alps, the effects of age, dominance and mating tactic on the likelihood of paternity were inferred within a Bayesian framework. In accordance with our hypothesis, reproductive success in male Alpine ibex was heavily biased towards older, dominant males that monopolized access to receptive females by adopting the ‘tending' tactic, while success among young, subordinate males via the sneaking tactic ‘coursing' was in general low and rare. In addition, we detected a high reproductive skew in male Alpine ibex, suggesting a large opportunity for selection. Compared with other ungulates with higher mortality rates, reproduction among young male Alpine ibex was much lower and more sporadic. Consistent with that, further examinations on the species level indicated that in polygynous ungulates the significance of early reproduction appears to decrease with increasing survival. Overall, this study supports the theory that survival prospects of males modulate the investments into reproduction via alternative mating tactics early in life. In the case of male Alpine ibex, the results indicate that their life-history strategy targets for long life, slow and prolonged growth and late reproductio

Leitfaden zum Monitoring von Wildhuftieren

Das Monitoring einheimischer Wildhuftier-Bestände ist ein grundlegendes Element des Wildtiermanagements, das in der Schweiz folgende Zielsetzungen verfolgt (gemäss Bundesgesetz über die Jagd und den Schutz wildlebender Säugetiere und Vögel JSG; SR 922.0): • den Schutz gefährdeter Arten, • dem Lebensraum angepasste Populationsgrössen mit möglichst natürlichen Bestandsstrukturen (Alters- und Geschlechterstruktur), • eine nachhaltige Jagd. Um diese Ziele zu gewährleisten bzw. verlässlich zu überprüfen, braucht es nach aktuellen Standards erhobene, gut dokumentierte Daten über Grösse, Entwicklung, Struktur, Zustand und Verbreitung von Wildtierbeständen. Zudem bilden diese Daten die Ausgangslage bei der Definition von jagdplanerischen Zielsetzungen (z.B. Stabilisierung/Senkung/Anhebung des Bestands; siehe Abb. 1) und dienen der Erfolgskontrolle bzw. Anpassung der umgesetzten Massnahmen im Sinne der rollenden Planung. Daten können mit diversen Monitoring-Methoden erhoben und analysiert werden, die sich zudem ständig weiterentwickeln. Die Arbeitsgruppe (AG) Wildhuftiere der Schweizerischen Gesellschaft für Wildtierbiologie (SGW) hat deshalb für alle im Management von Wildhuftieren tätigen Personen den vorliegenden Leitfaden erstellt. Darin werden die Parameter aufgelistet, die zur Beantwortung der wichtigsten Fragen im Huftiermanagement bekannt sein müssen, und die Monitoring-Methoden vorgestellt, die zur Erhebung dieser Parameter geeignet sind. Für jede einheimische Huftierart (Reh, Rothirsch, Wildschwein, Gämse, Steinbock) werden Empfehlungen gegeben, welche Standards ein Monitoring erfüllen soll, unter Abwägung der Aussagekraft und der Machbarkeit. Der Leitfaden entspricht dem aktuellen Wissens- und Erfahrungsstand und die Arbeitsgruppe möchte damit einen Beitrag an ein fachlich fundiertes Wildhuftiermanagement in der Schweiz leisten

OCCURRENCE OF FOOTROT IN FREE-RANGING ALPINE IBEX (CAPRA IBEX) COLONIES IN SWITZERLAND

Footrot is a worldwide economically important, debilitating disease caused by Dichelobacter nodosus. In sheep (Ovis aries), it is characterized by lesions of varying severity, depending on the strain, whereas Alpine ibex (Capra ibex) seem to develop severe lesions, whatever the strain. Healthy carriers occur in livestock but are rare in wild ruminants. Using a triangulation approach (retrospective questionnaire survey, necropsy database screening, and pathogen prevalence estimation in selected ibex colonies with and without footrot), we aimed at evaluating the importance of footrot in the ibex population, identifying potential risk factors for disease occurrence in this species, and defining the epidemiological role of ibex. Our study revealed that footrot occurs throughout the entire ibex territory (34% of the Swiss ibex colonies affected) but only as a sporadic disease (mostly one case per disease event), although the situation differed among footrot-positive colonies because half of them had experienced outbreak recurrences. Risk factor analysis for the occurrence of footrot in ibex colonies suggested an absence of an effect of meteorologic conditions, region, contacts with sheep or cattle (known to be very common healthy carriers of D. nodosus) and existing local disease control program. We found a significant effect only of contacts with sheep having footrot. Pathogen prevalence was very low in all investigated colonies. In conclusion, our results support previous data suggesting that ibex are susceptible spillover hosts, likely infected mainly by sympatric sheep displaying clinical signs