Deplacements Saisonniers Et Competition Vitale Entre Mouflons, Chamois Et Bouquetins Dans La Reserve Du Mercantour (Alpes Maritimes)

Pfeffer, Pierre; Settimo, Riccardo

doi:10.1515/mamm.1973.37.2.203

Cited by 9 publications

(6 citation statements)

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“…After that year, however, chamois stayed approximately constant, while ibex started to decrease. Therefore, testing whether competition between the two species (documented in Pfeffer & Settimo 1973) might be responsible for the decrease of ibex is worth exploring.…”

Section: Discussionmentioning

confidence: 99%

Sex‐ and age‐structured models for Alpine ibex Capra ibex ibex population dynamics

et al. 2012

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Past analysis has shown that the population dynamics of Alpine ibex Capra ibex ibex are regulated by both population density and winter snow accumulation. However, recent time series of the ibex counts in the Gran Paradiso National Park, Italy, show interesting trends in comparison with historical snow data: while the winter snow depth has steadily decreased since the beginning of the 1980s, the ibex population experienced rapid growth during the 1980s and the early 1990s, followed by a strong decrease. To explain these dynamics, we built novel age-structured population models in which demographic parameters depended on density and snow depth. They included a non-monotonic effect of snow depth and density on the vital rates, the age and sex structure of the population, and spatial segregation between females and males. Using information criteria (AIC c , BIC and SRM), we selected the best models and found that: 1) snow and density interacted in determining the demography of all population sex and age classes, thus confirming that unfavourable climatic conditions intensified the density dependence of the population, 2) the effect of snow was non-monotonic on weaning success and rate of demographic variation of kids, which were maximal for intermediate snow depths, and 3) accounting for spatial segregation between sexes improved the fitting of the models, which suggests that the different use of space made by males and females influenced intraspecific competition. When the selected models were recalibrated using past data and used to simulate recent trends, they underestimated both the rapid growth of the 1980s-1990s and the recent decline of the population. Using the novel sex-and age-structured models, we found that the underestimation of the peak was mainly due to deficiencies of adult demography models, while the overestimation of the recent population abundance was caused by shortcomings in the models of recruitment.

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Section: Discussionmentioning

confidence: 99%

Sex‐ and age‐structured models for Alpine ibex Capra ibex ibex population dynamics

et al. 2012

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“…the Alpine ibex (LATHAM 1999), but no apparent competition has been assessed between these species so far (PFEFFER & SETTIMO 1973;TOSI et al 1986). …”

Section: Discussionmentioning

confidence: 99%

Ranging behaviour and habitat selection of Alpine chamois

Nesti

Posillico

Lovari

2010

Ethology Ecology & Evolution

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Ranging behaviour and habitat selection of 23 male and 6 female adult (5-10 years old) Alpine chamois Rupicapra rupicapra (Linnaeus 1758) were monitored from February 2000 to December 2002, in an area of the Western Alps. The chamois were radio-located for a minimum of 4 and a maximum of 35 months, until failure of radio transmitters. A mean number of 13 locations/individual/month was recorded for a total of 7902 fixes. Adult males were divided in 19 residents (territorial males, with overlapping or adjacent warm and cold month ranges) and four migrants (with non-overlapping warm and cold month ranges, as well as attending higher altitude areas in the warm months). Home range and core area (kernel 95 and 50%, respectively) sizes of each individual were significantly greater in the warm (June-November) than in the cold (December-May) periods. During the warm period, home range and core area sizes significantly differed between resident (median home range: 49 ha; Q 1 -Q 3 : 31-110 ha) and migrant males (median home range: 749 ha; Q 1 -Q 3 : 539-850 ha), as well as between females (median home range: 711 ha; Q 1 -Q 3 : 388-1842 ha) and resident males. No significant difference was observed in the cold period. Home range size was not correlated to the presence of snow cover (≥ 70%). Throughout the year, nearly all chamois used south-to southeast-facing slopes. Resident males strongly preferred pastures and meadows, but four of them used alder shrublands on the north-east slope more than expected, in the warm months. Females kept nearly always at altitudes greater than those used by resident males and inhabited higher-quality areas.

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“…To warrant a homogeneity in the probability to detect the individuals of the 2 species, we separated observations in open areas from that performed in forests. Because most chamois and mouflon occupy open areas during the study period (Pfeffer and Settimo 1973, observations from GPS data, Loison et al unpubl. ), the mechanisms of coexistence occur probably mainly in the open pastures.…”

Section: Methodsmentioning

confidence: 99%

“…We then examined whether patterns of habitat selection by chamois and mouflon differed and determined the axes of their niche on which they overlap and segregate. We expect: 1) overlap in geographical space, reflecting the 2 species tracking the green‐up in spring (Pfeffer and Settimo 1973); 2) overlap on axes of the ecological niche correlated to productivity or resource quality (rich plant communities); 3) avoidance of chamois by mouflon and of mouflon by chamois due to possible competition, as the 2 populations are likely to be food limited (chamois population experience density‐dependence, exemplified by a decrease in offspring body mass, Garel et al pers. comm.…”

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confidence: 99%

Spatial distribution and habitat selection in coexisting species of mountain ungulates

et al. 2012

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One of the main objectives of community ecology is to understand the conditions allowing species to coexist, which requires identifying how co‐occurring species use and share space and resources. Species of the same trophic level, such as large herbivores, are of fundamental interest in that context because competition for resources is likely. Segregation in space or on some axes of the ecological niche are processes allowing coexistence, yet, both are seldom studied jointly. Based on annual spring censuses collected for 11 yr, we analysed the degree of overlap in spatial distribution among chamois Rupicapra rupicapra and mouflon Ovis gmelini musimon, 2 species of similar size that coexist on the same alpine pastures. We further investigated whether they differed in terms of habitat selection processes, and identified which environmental factors led to species being aggregated or segregated. The areas of intensive use for 2 species were more spatially aggregated than expected by chance. Habitat selection was studied using multivariate methods based on the niche concept, considering the presence of 1 species as an environmental variable for the other. Despite a large overlap in niches (88%), segregation was significant as chamois preferred meadows dominated by Sesleria and Carex sempervirens while mouflon selected meadows dominated by Carex ferruginea and avoided being close to areas affected by human activities. Importantly, habitat selection within each species was not affected by the presence of the other species. Coexistence between these 2 species and spatial overlap may be permitted because resource partitioning occurs at a fine temporal and/or spatial scale. We underscore that joint approaches of spatial and ecological processes are necessary to disclose the type of interaction (neutral, facilitation or competition) at play within a community.

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Deplacements Saisonniers Et Competition Vitale Entre Mouflons, Chamois Et Bouquetins Dans La Reserve Du Mercantour (Alpes Maritimes)

Cited by 9 publications

References 0 publications

Sex‐ and age‐structured models for Alpine ibex Capra ibex ibex population dynamics

Sex‐ and age‐structured models for Alpine ibex Capra ibex ibex population dynamics

Ranging behaviour and habitat selection of Alpine chamois

Spatial distribution and habitat selection in coexisting species of mountain ungulates

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