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Hunting lactating or non-lactating female ungulates is a debated issue because of offspring orphaning. Approaches based on individual-based modelling have been recently applied to investigate potential consequences of random hunting on lactating and non-lactating female chamois, and suggested that this management regime would have no effect on chamois population dynamics. We argue that this conclusion deserves great caution, and point out several uncertainties that should be accounted for in future agent-based models, thus in the decision-making process. Among the others: (i) the potential long-term effects on phenotypic quality and reproductive success of orphans, (ii) the local variation of chamois hunting season, which is likely to influence survival of orphans, (iii) the great variability of chamois hunting regimes throughout the species’ distribution range, (iv) the local variations in the assumed senescence in chamois and (v) the potential demographic consequences of trophy hunting when no restrictions on lactating females is imposed. Agent-based models may be useful tools for the adaptive management of wildlife populations: by investigating the potential outcomes of different harvesting regimes, first steps have been taken towards the application of this approach to chamois management. However, modelling of harvesting regimes requires extensive parametrization of the diversity of hunting regimes and their interconnections with life history traits to obtain more generalizable recommendations.
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Ethology Ecology & Evolution
ISSN: 0394-9370 (Print) 1828-7131 (Online) Journal homepage:
Hunting lactating female ungulates deserves
caution: the case of the chamois
Luca Corlatti, Francesco Ferretti & Sandro Lovari
To cite this article: Luca Corlatti, Francesco Ferretti & Sandro Lovari (2019) Hunting lactating
female ungulates deserves caution: the case of the chamois, Ethology Ecology & Evolution, 31:3,
293-299, DOI: 10.1080/03949370.2018.1561526
To link to this article:
Published online: 26 Feb 2019.
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Hunting lactating female ungulatesdeservescaution:thecaseofthe
The Northern chamois R. rupicapra is one of the most abundant mountain-
dwelling ungulates in Europe and the Near East (Corlatti et al. 2011) and an iconic
symbol of mountain hunting. Despite its overall abundance, some populations of the
Alpine subspecies R. r. rupicapra lately showed a decreasing trend and other subspe-
cies are threatened (Corlatti et al. 2011). As hunting pressure is one of the major
drivers of population dynamics in game species, understanding the potential demo-
graphic consequences of different harvesting regimes is pivotal to ensure sustainable
wildlife management. In a paper on chamois population dynamics, Rughetti and
Festa-Bianchet (2014) adopted an individual-based modelling approach to explore
the consequences of different hunting regimes on several demographic parameters.
The theoretical rationale of this work is based on the potential demographic conse-
quences of hunting regulations and/or hunter preferences that, in many large mam-
mals, currently discourage harvesting of lactating females (Solberg et al. 2000; Bischof
et al. 2009; Mysterud 2011). In turn, this may cause a selective pressure on subadult,
non-lactating females (Rughetti & Festa-Bianchet 2011b) who may enjoy high natural
survival and high lifetime reproductive potential. It is thus suspected that removing
a relatively greater proportion of these young females could possibly lead to a severe
impact on population dynamics. Using varying levels of hunting pressure and of
relative survival probability of orphan vs non-orphan kids (0.5; 1), the authors mod-
elled the theoretical long-term effects of random hunting (i.e. harvesting of yearlings
and 2 years old females, irrespective of their reproductive status) and those of
selective hunting (i.e. harvesting of yearlings and 2 years old non-lactating females)
on chamois population size at equilibrium, age structure, hunting mortality of differ-
ent age classes and recruitment. The key result of this analysis is that depending on
the effects of orphaning on juvenile survival, selective harvest may either increase or
decrease population growth rate compared to random harvest(Rughetti & Festa-
Bianchet 2014). In the final part of the paper, the authors suggest that removing the
penalty of hunting lactating females would have no effect on chamois population
dynamics, while leaving hunters with the opportunity to select a non-lactating female
if they wish(Rughetti & Festa-Bianchet 2014). While we agree that that more infor-
mation on the effects of orphaning on juvenile survival is needed to elucidate the best
hunting strategy, in this article we argue that several other uncertainties should be
accounted for in future agent-based models, thus in the decision-making process, to
obtain generalizable recommendations.
Ethology Ecology & Evolution, 2019
Vol. 31, No. 3, 293299,
© 2019 Dipartimento di Biologia, Università di Firenze, Italia
Uncertainties on short- and long-term consequences of orphaning
Data on the effects of orphaning on survival of chamois offspring are missing
(Rughetti & Festa-Bianchet 2014). Furthermore, as far as ungulates are concerned,
available information is scanty and contradictory (Festa-Bianchet et al. 1994; Andres
et al. 2013; see other references in Rughetti & Festa-Bianchet 2014). Understandably,
the authors decided to run a sensitivity analysis assuming two values for relative
survival probability of orphaned kids to test for the bestand the worstscenario:
(i) equal survival between orphans and non-orphans, (ii) orphan survival is 50% of
non-orphan survival.
Early growth and/or survival of offspring could be influenced by the condi-
tion of their mothers and the amount of maternal care (e.g. Clutton-Brock et al.
1984,1986; Festa-Bianchet 1988;Côté&Festa-Bianchet2001a). In turn, the
removal of mothers during the nursing period is likely to affect early growth,
hence survival of offspring. Thus, we may expect that the time of hunting will
play an important role in shaping survival probability of orphans. The analysis of
Rughetti and Festa-Bianchet (2014) does not explicitly state the time of hunting,
although it is likely assumed to occur in Autumn. However, chamois hunting
seasons vary greatly across regions and hunting districts, ranging between early
August and late February (Apollonio et al. 2011;Damm&Franco2014). Even if
we assume that offspring losing their mother near or after weaning might not
suffer increased mortality (Festa-Bianchet et al. 1994;butseeAndresetal.2013
and paragraphs above), consequences could be comparatively heavier for those
losing their mother over the summer. In turn, summer orphaning may greatly
impact on chamois kid survival, as long as some regulations allow hunting to
occur well within the period of intensive maternal care (i.e. until mid
September-early October, for chamois, Ruckstuhl & Ingold 1994; Scornavacca
et al. 2016,2018). Whether the currently used bounds 050% of orphan survival
are valid in these circumstances still has to be clarified: in mountain goats
Oreamnos americanus, for example, only one out of eight kids who lost their
mother during summer survived to 1 year of age (Côté & Festa-Bianchet 2001b).
If so, future agent-based models ought tousedifferentboundstomodelorphan
survival probabilities depending on the period of hunting.
Furthermore, in chamois, offspring stay with their mothers well after wean-
ing, until about 1 year of age. Beside lactation, juveniles benefit from bonding
with mothers by increasing protection against predators, defence from aggression
by conspecifics, social cohesion in herds, and by learning patterns of habitat use,
movements and food selection (e.g. Clutton-Brock et al. 1982; Green et al. 1989;
Andres et al. 2013). Ruckstuhl and Ingold (1999)foundthatinchamoisafter
suckling frequency declined over summer the mother-kid bond remained strong,
possibly to favour the synchronisation of activities (cf. Romeo & Lovari 1996,for
mountain goats). Thus, the consequences of maternal loss are unlikely to be
related solely to the cessation of milk supply, when orphaning will likely foster
an increase of kid vulnerability to starvation and/or predation (Apollonio et al.
Orphaning, however, may not only exert short-term effects but also far less
predictable long-term effects not included in the model. In mammals, conditions
experienced early in life influence conditions in adulthood (e.g. Lindström 1999;
Lummaa & Clutton-Brock 2002; Douhard et al. 2013) and affect life-history traits
294 Forum
such as individual reproductive success (e.g. Clutton-Brock et al. 1984,1986).
Although information on the long-term effects of orphaning are scarcer than those
available on short-term impacts, Festa-Bianchet et al. (1994) and Andres et al. (2013)
showed that, in males, body and horn/antler growth could be reduced. In some
species, these traits correlate directly or indirectly with male reproductive success
(Geist 1971; Clutton-Brock et al. 1982; Festa-Bianchet et al. 2000). Furthermore,
orphaning may exert negative effects in terms of stress response, reduced maternal
behaviour or augmentation of fear and aggression (for a review, see Apollonio et al.
2011). Rughetti and Festa-Bianchet (2014) mentioned potential long-term conse-
quences of orphaning on phenotypic quality (i.e. body mass and weapon growth)
and reproductive success of offspring. While we acknowledge the difficulty of incor-
porating such information in agent-based models, these potential effects on long-term
population dynamics are likely to increase model uncertainty.
What is a senescent chamois?
Rughetti and Festa-Bianchet (2014) assumed the occurrence of senescence in
females 9 years of age, yet large variations occur in the pattern of senescence in
chamois populations. From a reproductive point of view, breeding success in the Swiss
Alps declined only in females older than 16 years (Tettamanti et al. 2015). From
a survival point of view, Loison et al. (1994) did not find any significant decrease of
survival rate in Alpine chamois females until 13.5 years of age, whilst in different areas
of the Alps the onset of senescence may occur as early as 7 years or much later, at
about 12 years of age (Bleu et al. 2015). For example, Corlatti et al. (2012), for
a protected stable population of Alpine chamois, found out that females 8 years of
age enjoyed a survival rate of 0.92, much greater than the 0.70 value assumed by
Rughetti and Festa-Bianchet (2014). The effects of variation in female senescence
should thus be accounted for in future agent-based models.
Does a typical chamois hunting regime exist?
Although Rughetti and Festa-Bianchet (2014) assumed that the typical hunting
regulation implies separate harvest rates for adult and yearling females, harvesting of
yearlings and of 2 years old females is far from being the typical chamois hunting
system. Over the distribution range of this ungulate one can find quite a variety of
management regimes (Damm & Franco 2014). In parts of Italy, for instance, females
are grouped into four (1, 23, 410 and 11 years old) or three (1, 23, 4 years old)
age classes, whereas in Austria females are grouped into three age classes (13, 49,
10 years of age) (Damm & Franco 2014). Moreover, despite the authorsassumption
that the absence of kid harvesting is typical of most hunted populations, hunting of
kids occurs in many chamois populations over the Alpine arch, e.g. in Austria and
Germany (that alone accounts for some 38% of the total Alpine chamois hunting bag
in Europe: Damm & Franco 2014), in Switzerland (Damm & Franco 2014) and in
France (Garel et al. 2009). This variability needs to be accounted for when evaluating
the performance of random vs selective harvesting. For example, it could be expected
that in hunting regimes in which fixed hunting quotas are assigned to more than two
female age-classes there would be less opportunity for overharvesting young and
Forum 295
productive females, while in hunting regimes where kids are allowed to be shot, the
removal of penalty for hunting lactating females and consequent kid orphaning could
possibly exert an over-impact on kid survival.
Random harvestor not?
Given the very limited sexual dimorphism of chamois, especially before and after
the rutting season, in November (when males weigh 3040% more than females; Garel
et al. 2009; Rughetti & Festa-Bianchet 2011a), if hunters are left with the choice to
hunt either lactating or non-lactating females, they may over-impact on females with
kids, to avoid the risk of culling males by error. This bias was anecdotally reported by
Italian hunters (i.e. in some districts of the Province of Brescia, where there are no
restrictions on lactating females). Furthermore, Corlatti et al. (2017) recently showed
that while in hunting regimes with restrictions on lactating females there is no selec-
tion for female trophies, in hunting regimes with no restrictions on lactation status
female chamois can become a target for trophy hunters i.e. there is a strong negative
relationship between early horn growth and survival. This, in turn may have important
consequences for the dynamics of populations: as a matter of fact, female chamois
with rapid horn growth as yearlings reproduce earlier, and early horn growth proved
a reliable index of reproductive potential in young and senescent female chamois
(Rughetti & Festa-Bianchet 2011b). More generally, early primiparity positively associ-
ates with larger body mass, longer life expectancy and greater fitness in ungulates (cf.
Rughetti & Festa-Bianchet 2011b). By removing the penalty for hunting lactating
females, trophy hunters may thus preferentially remove long-horned, early primipar-
ous females at an early age, possibly making the random harvest, de facto, a non-
random regime targeted towards the most productive segment of the population. This
effect might be exacerbated by the occurrence of individual heterogeneity in female
reproductive performance (i.e. successful females chamois tend to be consistently
better than the unsuccessful ones in subsequent reproductive events; Tettamanti
et al. 2015). The level of individual heterogeneity may indeed play a major role when
evaluating the demographic consequences of different hunting regimes (i.e. negative
effects are most likely to occur when a random harvest regime is adopted in the
presence of strong individual heterogeneity) (Rughetti et al. 2017), and thus needs to
be accounted for in future agent-based models.
Concluding remarks
Agent-based models can be useful tools for preliminary evaluation of potential
effects of different options within the framework of adaptive management of wildlife
populations. The work of Rughetti and Festa-Bianchet (2014) represents a first
attempt to apply this approach to chamois. However, uncertainty is pervasive in
ecological systems, and multiple types of uncertaintysuch as stochastic variability,
sampling imprecision, observation errors and model errors may affect the accuracy
and precision of modelling outputs(Hoshino et al. 2014). Some real systems may be
irreducibly complex and, although they can still be treated by agent-based models, the
outcome may have fundamental limitations and, possibly, restricted range of validity
(Helbing 2012). We have argued that the model proposed by Rughetti and Festa-
296 Forum
Bianchet (2014) does not capture the great spatial heterogeneity in chamois life history
traits, variety of hunting regimes, and the potential selective consequences of random
female harvest. Consequently, we believe that the authorssuggestion that removing
the penalty for hunting lactating females, assuming kid orphaning would have no
effect on chamois population dynamics, while leaving hunters with the opportunity to
select a non-lactating female if they wish(Rughetti & Festa-Bianchet 2014) might
have local value, but deserves great caution if the readers wish to apply that to other
chamois populations. Further uncertainty components in the model parametrization
need to be carefully evaluated, to avoid misleading management recommendations.
Among the others: (i) the potential long-term effects on phenotypic quality and repro-
ductive success of orphans, (ii) the local variation of chamois hunting season, which is
likely to influence survival of orphans, (iii) the great variability of chamois hunting
regimes throughout the speciesdistribution range, (iv) the local variations in the
assumed senescence in chamois and (v) the potential demographic consequences of
trophy hunting when no restrictions on lactating females is imposed.
Agent-based models may be useful tools for the adaptive management of wildlife
populations: first steps have been taken towards the application of this approach to
chamois management by investigating the potential outcomes of different harvesting
regimes. Future modelling attempts should account for the diversity of hunting
regimes and for their interconnections with chamois life history traits, to obtain
more general and reliable insights into the long-term demographic consequences of
different chamois management options. Given the current uncertainties, we strongly
caution against the adoption of a hunting regime which includes kid orphaning, and
suggest that selective harvesting combined with the adoption of hunting quotas for
different female age classes may effectively reduce the pressure on young females with
high reproductive value, while avoiding the negative effects of trophy hunting and all
the uncertainties ethical issues included of orphaning.
Disclosure statement
No potential conflict of interest was reported by the authors.
Andres D, Clutton-Brock TH, Kruuk LEB, Pemberton JM, Stopher KV, Ruckstuhl KE. 2013.
Sex differences in the consequences of maternal loss in a long-lived mammal, the red deer
(Cervus elaphus). Behav Ecol Sociobiol. 67:12491258.
Apollonio M, Putman R, Grignolio S, BartošL. 2011. Hunting seasons in relation to biological
breeding seasons and the implications for the control or regulation of ungulate popula-
tions. In: Putma n R , et al., editors. Ungulate management in Europe: problems and
practices. Cambridge: Cambridge University Press; p. 80105.
Bischof R, Swenson JE, Yoccoz NG, Mysterud A, Gimenez O. 2009. The magnitude and
selectivity of natural and multiple anthropogenic mortality causes in hunted brown bears.
J Anim Ecol. 78:656665.
Bleu J, Herfindal I, Loison A, Kwak AMG, Garel M, Toïgo C, Rempfler T, Filli F, Sæther BE.
2015. Age-specific survival and annual variation in survival of female chamois differ
between populations. Oecologia. 179:10911098.
Clutton-Brock TH, Albon SD, Guinness FE. 1984. Maternal dominance, breeding success and
birth sex ratios in red deer. Nature. 308:358360.
Clutton-Brock TH, Albon SD, Guinness FE. 1986. Great expectations: dominance, breeding
success and offspring sex ratios in red deer. Anim Behav. 34:460471.
Forum 297
Clutton-Brock TH, Guinness FE, Albon SB. 1982. Red deer: behavior and ecology of two sexes.
Chicago (IL): The University of Chicago Press.
Corlatti L, Lebl K, Filli F, Ruf T. 2012. Unbiased sex-specific survival in Alpine chamois.
Mamm Biol. 77:135139.
Corlatti L, Lorenzini R, Lovari S. 2011. The conservation of the chamois Rupicapra spp.
Mammal Rev. 41:163174.
Corlatti L, Storch I, Filli F, Anderwald P. 2017. Does selection on horn length of males and
females differ in protected and hunted populations of a weakly dimorphic ungulate? Ecol
Evol. 7:37133723.
Côté SD, Festa-Bianchet M. 2001a. Reproductive success in female mountain goats: the influ-
ence of age and social rank. Anim Behav. 62:173181.
Côté SD, Festa-Bianchet M. 2001b. Birthdate, mass and survival in mountain goat kids: effects
of maternal characteristics and forage quality. Oecologia. 127:230238.
Damm GR, Franco N. 2014. CIC Caprinae atlas of the world. Budakeszi (Hungary): CIC
International Council for Game and Wildlife Conservation [in cooperation with
Johannesburg (South Africa): Rowland Ward Publications].
Douhard M, Gaillard J-M, Delorme D, Capron G, Duncan P, Klein F, Bonenfant C. 2013.
Variation in adult body mass of roe deer: early environmental conditions influence early
and late body growth of females. Ecology. 94:18051814.
Festa-Bianchet M. 1988. Nursing behaviour of bighorn sheep: correlates of ewe age, parasitism,
lamb age, birthdate and sex. Anim Behav. 36:14451454.
Festa-Bianchet M, Jorgenson JT, Réale D. 2000. Early development, adult mass, and repro-
ductive success in bighorn sheep. Behav Ecol. 11:633639.
Festa-Bianchet M, Jorgenson JT, Wishart WD. 1994. Early weaning in bighorn sheep, Ovis
canadensis, affects growth of males but not of females. Behav Ecol. 6:2127.
Garel M, Loison A, Jullien J-M, Dubray D, Maillard D, Gaillard J-M. 2009. Sex-specific
growth in alpine chamois. J Mammal. 90:954960.
Geist V. 1971. Mountain sheep. Chicago (IL): Chicago Press.
Green WCH, Griswold JG, Rothstein A. 1989. Post-weaning associations among bison mothers
and daughters. Anim Behav. 38:847858.
Helbing D. 2012. Social self-organization agent-based simulations and experiments to study
emergent social behavior. Berlin-Heidelberg: Springer.
Hoshino E, Milner-Gulland EJ, Hillary RM. 2014. Why model assumptions matter for natural
resource management: interactions between model structure and life histories in fishery
models. J Appl Ecol. 51:632641.
Lindström J. 1999. Early development and fitness in birds and mammals. Trends Ecol Evol.
Loison A, Gaillard J-M, Houssin H. 1994. New insight on survivorship of female chamois
(Rupicapra rupicapra) from observation of marked animals. Can J Zool. 72:591597.
Lummaa V, Clutton-Brock TH. 2002. Early development, survival and reproduction in humans.
Trends Ecol Evol. 17:141147.
Mysterud A. 2011. Selective harvesting of large mammals: how often does it result in directional
selection? J Appl Ecol. 48:827834.
Romeo G, Lovari S. 1996. Summer activity rhythms of the Mountain goat Oreamnos americanus
(de Blainville, 1816). Mammalia. 60:496499.
Ruckstuhl KE, Ingold P. 1994. On the suckling behaviour of Alpine chamois, Rupicapra rupi-
capra rupicapra. Z Saeugetierkd. 59:230235.
Ruckstuhl KE, Ingold P. 1999. Aspects of mother-kid behavior in Alpine chamois, Rupicapra
rupicapra rupicapra. Z Saeugetierkd. 64:7684.
Rughetti M, Festa-Bianchet M. 2011a. Seasonal changes in sexual size dimorphism in northern
chamois. J Zool. 284:257264.
Rughetti M, Festa-Bianchet M. 2011b. Effects of early horn growth on reproduction and
hunting mortality in female chamois. J Anim Ecol. 80:438447.
298 Forum
Rughetti M, Festa-Bianchet M. 2014. Effects of selective harvest of non-lactating females on
chamois population dynamics. J Appl Ecol. 51:10751084.
Rughetti M, Festa-Bianchet M, Côté SD, Hamel S. 2017. Ecological and evolutionary effects of
selective harvest of non-lactating female ungulates. J Appl Ecol. 54:15711580.
Scornavacca D, Cotza A, Lovari S, Ferretti F. 2018. Suckling behaviour and allonursing in the
Apennine chamois. Ethol Ecol Evol. 30:385398.
Scornavacca D, Lovari S, Cotza A, Bernardini S, Brunetti C, Pietrocini V, Ferretti F. 2016.
Pasture quality affects juvenile survival through reduced maternal care in a
mountain-dwelling ungulate. Ethology. 122:111.
Solberg EJ, Loison A, Saether BE, Strand O. 2000. Age-specific harvest mortality in
a Norwegian moose Alces alces population. Wildl Biol. 6:4152.
Tettamanti F, Grignolio S, Filli F, Apollonio M, Bize P. 2015. Senescence in breeding success
of female Alpine chamois (Rupicapra rupicapra): the role of female quality and age.
Oecologia. 178:187195.
Wildlife Ecology and Management, University of Freiburg, Tennenbacher Straße 4,
79106 Freiburg, Germany and Institute of Wildlife Biology and Game Management,
University of Natural Resources and Life Sciences Vienna, Gregor-Mendel Strasse 33,
A-1180 Vienna, Austria.
Research Unit of Behavioural Ecology, Ethology and Wildlife Management,
Department of Life Sciences, University of Siena, Via P.A. Mattioli 4, 53100 Siena,
Research Unit of Behavioural Ecology, Ethology and Wildlife Management,
Department of Life Sciences, University of Siena, Via P.A. Mattioli 4, 53100 Siena,
Italy. and Maremma Natural History Musem, Strada Corsini 5, 58100 Grosseto, Italy
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... Hunting of kids occurs in many chamois populations over the Alpine arch, e.g., in Austria, Germany, Switzerland, and in France (Damm and Franco 2014). Opportunities and pitfalls of hunting lactating female chamois, in particular, have recently been discussed by Rughetti and Festa-Bianchet (2014) and Corlatti et al. (2019b). In the Alps, hunting generally follows the principle of sustainable hunting: in increasing populations (e.g., below carrying capacity) chamois growth rate normally varies between 5% and 15% (cf. ...
... Hunting of kids occurs in many chamois populations over the Alpine arch, e.g., in Austria, Germany, Switzerland, and in France (Damm and Franco 2014). Opportunities and pitfalls of hunting lactating female chamois, in particular, have recently been discussed by Rughetti and Festa-Bianchet (2014) and Corlatti et al. (2019b). In the Alps, hunting generally follows the principle of sustainable hunting: in increasing populations (e.g., below carrying capacity) chamois growth rate normally varies between 5% and 15% (cf. ...
[Published in: Handbook of the Mammals of Europe – Terrestrial Cetartiodactyla (Eds. Zachos, F. and L. Corlatti). Springer Nature.] The chamois is the most abundant mountain ungulate of Europe. Although the taxonomy of the genus has been subject to continuous revisions since the beginning of the twentieth century, currently two species are recognized: the Northern chamois Rupicapra rupicapra, and the Southern chamois Rupicapra pyrenaica. In this chapter we follow this classification, and present an up-to-date synthesis of the biology, ecology, behaviour and conservation status of the two species. After introducing the taxonomic status and the recent controversies surrounding the systematic of the genus, we provide an account of the current distribution of the chamois within its native range, from the Cantabrians to the Caucasus, from Poland to Turkey. For both species, we describe: the main morphological, physiological and genetic features; an overview of the main life history traits (growth, survival and reproduction); the relationships between chamois and its environment (space use, diet) and how internal and external variables impact on the dynamics of its populations, including competition with wild and domestic ungulates; its social behaviour throughout the year and male mating system; the most relevant diseases and their demographic impacts; the issues surrounding its management and conservation. This chapter will provide researchers and people interested in chamois with the opportunity to access the most relevant advances on the biology of these iconic species.
... Für die Ermittlung nachhaltiger Nutzungsraten ist jedoch die allgemeine Geburtenrate (auch Zuwachsrate genannt) maßgebend. Sie gibt den Verhältniswert von allen Kitzen zur Gesamtzahl aller Individuen ab einem vollendeten Jahr an und liegt im Bereich von 5 bis 15 %(CORLATTI et al. 2019a). Sie ist natürlich auch abhängig von der Genauigkeit, mit der die Gesamtzahl der Population bestimmt werden kann. ...
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The situation and management approach of Alpine chamois (Rupicapra r.r.) is evaluated especially in relation to conservations regulations by the EU. We give an overview of the monitoring of the population status in the alpine countries (with the exception of Liechtenstein and Romania) and the efforts taken respectively to ensure sustainable hunting of the species in view of its listing in Annex V of the ffh-directive.
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Maternal cares and, in particular, suckling behaviour, are fundamental for early growth and survival of offspring ungulates. In turn, factors influencing maternal cares can have important effects at individual and population levels, with consequences at both short and long temporal scales. We assessed monthly variation of behavioural indices of suckling and nursing, as well as occurrence of allosuckling, in a mountain-dwelling ungulate, the Apennine chamois Rupicapra pyrenaica ornata, on summer-early autumn 2013–2014. Not surprisingly, duration of suckling events and frequency of suckling solicitations by kids, decreased throughout months, whereas the proportion of grazing kids increased from July to October, indicating a growing reliance on pasture. Conversely, the probability of suckling success kept stable from July to October, suggesting a constant willingness of females to allow kids to suckle. Of all suckling events, 63% involved more than one kid, indicating allosuckling. On average, multiple suckles were shorter than those involving one kid and occurred in all months with the same proportion. Our results suggest the occurrence of high levels of maternal cares in a gregarious herbivore, with frequent allosuckling and apparent willingness of females to nurse offspring throughout summer-autumn. These results suggest that the mother’s role does not terminate with weaning.
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Weaponry in ungulates may be costly to grow and maintain, and different selective pressures in males and females may lead to sex-biased natural survival. Sexual differences in the relationship between weapon growth and survival may increase under anthropogenic selection through culling, for example because of trophy hunting. Selection on weaponry growth under different scenarios has been largely investigated in males of highly dimorphic ungulates, for which survival costs (either natural or hunting-related) are thought to be greatest. Little is known, however, about the survival costs of weaponry in males and females of weakly dimorphic species. We collected information on horn length and age at death/shooting of 407 chamois Rupicapra rupicapra in a protected population and in two hunted populations with different hunting regimes, to explore sexual differences in the selection on early horn growth under contrasting selective pressures. We also investigated the variation of horn growth and body mass in yearling males (n=688) and females (n=539) culled in one of the hunted populations over 14 years. The relationship between horn growth and survival showed remarkable sexual differences under different evolutionary scenarios. Within the protected population, under natural selection, we found no significant trade-off in either males or females. Under anthropogenic pressure, selection on early horn growth of culled individuals showed diametrically opposed sex-biased patterns, depending on the culling regime and hunters’ preferences. Despite the selective bias between males and females in one of the hunted populations, we did not detect significant sex-specific differences in the long-term pattern of early growth. The relationship between early horn growth and natural survival in either sex might suggest stabilizing selection in horn size in chamois. Selection through culling can be strongly sex-biased also in weakly dimorphic species, depending on hunters’ preferences and hunting regulations, and long-term data are needed to reveal potential undesirable evolutionary consequences.
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Female ungulates are often selectively harvested according to their reproductive status. Because ungulate population growth depends heavily on adult female survival, it is crucial to understand the effects of this selective harvest. Recent studies revealed persistent individual differences in female reproductive potential, with a positive correlation of reproductive success over consecutive years. If current reproduction is correlated with lifetime reproductive success, then selective harvest of non‐lactating females should remove individuals of low reproductive potential, with lower impact on population growth than random harvest. If lifetime reproductive success has a genetic basis, selective harvest may also increase the proportion of successful females. We used an individual‐based model to understand the short‐term effects of harvest intensity and hunter selectivity on population dynamics, accounting for both heterogeneity in reproductive potential and orphan survival. We also explored the long‐term effect of harvest as a selective pressure on female heterogeneity. Selective harvest of non‐lactating females reduced survival to primiparity compared to random harvest, because of high harvest rates of pre‐reproductive females. After primiparity, however, females of higher reproductive potential had higher survival under selective than random harvest. Therefore, the overall effect on population dynamics depends on a trade‐off between a high harvest of pre‐reproductive females and a reduced harvest of reproductive females with high reproductive potential. Female heterogeneity and the length of the pre‐reproductive period affected this trade‐off. Over the short term, high heterogeneity in reproductive potential of pre‐reproductive females made selective harvest the most effective strategy to maintain a high population growth rate. With low heterogeneity and little effects of orphaning on juvenile mortality, however, random harvest had a lower impact on population growth than selective harvest. Over the long term, selective female harvest may increase the proportion of successful reproducers in the population. Synthesis and applications . Selective harvests of non‐lactating females appear justified only if female heterogeneity in reproductive potential and/or orphan mortality are very high. Because pre‐reproductive females will be subject to intense harvest, selective harvest may reduce population growth rate compared to random harvest in species with late primiparity, especially if most pre‐reproductive female normally survive to primiparity. When heterogeneity in reproductive potential and orphan mortality are low, random female harvest appears preferable to selective harvest.
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In many species, population dynamics are shaped by age-structured demographic parameters, such as survival, which can cause age-specific sensitivity to environmental conditions. Accordingly, we can expect populations with different age-specific survival to be differently affected by environmental variation. However, this hypothesis is rarely tested at the intra-specific level. Using capture-mark-recapture models, we quantified age-specific survival and the extent of annual variations in survival of females of alpine chamois in two sites. In one population, survival was very high (>0.94; Bauges, France) until the onset of senescence at approximately 7 years old, whereas the two other populations (Swiss National Park, SNP) had a later onset (12 years old) and a lower rate of senescence. Senescence patterns are therefore not fixed within species. Annual variation in survival was higher in the Bauges (SD = 0.26) compared to the SNP populations (SD = 0.20). Also, in each population, the age classes with the lowest survival also experienced the largest temporal variation, in accordance with inter-specific comparisons showing a greater impact of environmental variation on these age classes. The large difference between the populations in age-specific survival and variation suggests that environmental variation and climate change will affect these populations differently.
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Although numerous studies have reported reproductive senescence in wild animal populations, we still know very little on inter-individual differences in rates of ageing and on the factors accounting for these differences. To investigate age-related variation in breeding success in a natural population of Alpine chamois (Rupicapra rupicapra), we used 15 years of data obtained by monitoring individual ear-tagged females. Analyses at the population level confirmed the occurrence of a decline in female breeding success, which is most noticeable from 9 years of age onward. Using an age-reverse approach, we showed that senescence in female breeding success occurs at the same age, since only very old individuals (older than 16 years) showed a decline in breeding success in the years preceding death. Interestingly, we also found evidence that 'success comes from success', as females that gave birth in a given year were more likely to procreate again in the following year. Moreover, results showed that discrepancies between successful and unsuccessful individuals tend to become more relevant in the oldest age classes. There was no evidence of a terminal allocation. These results emphasize the importance of age-dependent effects and individual quality in shaping reproductive senescence in a wild long-lived ungulate.
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In large mammals, regulations or hunter preference often lead to selective harvest of non‐lactating females, with unknown impacts upon population growth. Because female survival has very high elasticity effects on population growth, an assessment of the magnitude and selectivity of female harvest is crucial to understand population dynamics of sport‐hunted ungulates. Hunting accounts for most mortality of adult chamois Rupicapra rupicapra and regulations typically discourage the harvest of lactating females as orphaned kids have reduced survival rates. We used an individual‐based model, produced from empirical data, to explore the effects of selective removal of non‐lactating females on chamois population dynamics. Harvest intensity had much stronger effects on female population dynamics than selectivity for reproductive status. Selective harvest of non‐lactating females had very weak effects on population size and then only at a high harvest rate and under strong selectivity. Assuming no difference in winter survival between orphaned and non‐orphaned kids, harvest of non‐lactating females decreased population size at equilibrium compared to a random female harvest, whereas the opposite was true when assuming 50% lower survival of orphaned kids. Selective harvest of non‐lactating females may avoid the negative effects of orphaning on juvenile survival, but increases mortality of pre‐reproductive females that normally enjoy high survival and have high reproductive value. Synthesis and applications . The impact of selective harvest of non‐lactating females upon population dynamics is likely to be more affected by the age structure of lactating and non‐lactating females rather than by the survival of orphan and non‐orphan juveniles. High harvest of pre‐reproductive females has undesirable effects on population dynamics, which must be considered alongside any cultural preferences of hunters when developing hunting regulations or policies.
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In temperate environments, early-born ungulates may enjoy a longer growth period before winter, and so attain a higher body mass and an increased probability of survival compared to late-born ones. We assessed the effects of maternal characteristics, forage quality and population density on kid birthdate, mass and survival in a population of marked mountain goats (Oreamnos americanus) in Alberta. The duration and timing of the birth season were similar in all years. Births were highly synchronised: 80% of kids were born within 2 weeks of the first birth. Maternal age, maternal social rank and density did not affect kid birthdate or mass. Previous breeding experience was not related to kid birthdate, but kids born to pluriparous mothers were heavier during summer than kids born to primiparous mothers. Male and female kids had similar mass and accumulated mass linearly during summer. Early-born kids were heavier than late-born kids. Faecal crude protein (FCP) in late spring and maternal mass were positively related to kid mass. Survival to weaning appeared higher for males (90%) than for females (78%), but survival to 1 year was 65% for both sexes. FCP in late spring, density, birthdate and mass did not affect kid survival to weaning in either sex. Survival to 1 year increased with FCP in late spring for females, but not for males. Survival to 1 year was independent of birthdate for both sexes, but heavy females survived better than light ones. Multiple logistic regression revealed a positive effect of mass on survival to 1 year when the sexes were pooled. Our results suggest that mountain goats are constrained to give birth in a short birth season synchronised with forage productivity.
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.
Mammalian Biology j o u r n a l h o m e p a g e : w w w . e l s e v i e r . d e / m a m b i o a b s t r a c t 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 grow-ing 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.
Bioeconomic models are increasingly used to provide benchmarks for harvest levels in wildlife and natural resource management, yet uncertainties related to model structure are underexplored. We investigate the importance of a range of uncertainties with a focus on model structure and life histories when estimating bioeconomic target reference point ( TRP s) and assess the policy implications of ignoring these uncertainties. We use three contrasting case studies to investigate the interactions between model, observational and process errors related to life‐history parameters: the short‐lived Japanese common squid Todarodes pacificus and Pacific saury Cololabis saira , and the slow‐growing Patagonian toothfish Dissostichus eleginoides . We developed a simulation framework to test the harvest strategies resulting from bioeconomic TRP s under various assumptions about model structures and parameters. We found the relative importance of different types of uncertainties affecting precision and accuracy of the model outputs varied according to the life‐history traits. Little difference in TRP estimates was found between simple vs. complex population models for saury, while large differences were found for toothfish. The assumptions made about stock structure for squid not only resulted in different TRP estimates (generally, smaller for the multistock models), but also different economic outcomes depending on the balance of effort allocation between stocks. Synthesis and applications . We use models similar to those used in the actual management of three case study species to explore the effects of interacting uncertainties on the management advice. We show that the interactions between structural elements of the models lead to very different management advice, depending on the life history of the species concerned. For the long‐lived toothfish, life‐history and gear selectivity parameters interacted strongly. For the short‐lived squid which is managed as two stocks, spatial fishing effort allocation, correlation of environmental drivers between stocks and differential stock productivity interacted, producing very poor economic performance if assumptions about stock structure are incorrect. The key message for model‐based natural resource management is that it is vital to investigate the major uncertainties related to model structure, process and estimation errors simultaneously, because they interact to produce non‐intuitive results.