Joint effects of weather and interspecific competition on foraging behavior and survival of a mountain herbivore

Ferretti, Francesco; Lovari, Sandro; Stephens, Philip A.

doi:10.1093/cz/zoy032

Cited by 19 publications

(29 citation statements)

References 77 publications

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“…High-quality, cold-adapted forb patches domi-nated by Trifolium thalii and other legumes are the most nutritious food resources for chamois (Ferrari et al, 1988;Lovari et al, 2014), as well as the most selected ones (Ferrari et al, 1988;Ferretti et al, 2014). Forb-dominated patches are more abundant in area R (24.5% of cover) than in areas P1 and P2 (~15% of cover), whereas patches dominated by unpal-atable B. genuense are widespread in areas P1 and P2 (~11-25%) but very rare in area R (~1%) (Ferretti et al, 2015).…”

Section: Study Areas and Populationsmentioning

confidence: 99%

“…Pasture depletion resulted in a high winter mortality of kids, for the 'vul-nerable' [sensu International Union for Conservation of Nature (IUCN); Herrero et al, 2008] Apennine chamois, in the core of its historical distribution (Lovari et al, 2014;Ferretti et al, 2015;Scornavacca et al, 2016). The negative effects of changes in weather phenology on vegetation grazed by chamois (Ferretti et al, 2018), the spread of unpalatable tall grasses in secondary meadows (Lovari et al, 2014;Corazza et al, 2016) and increased resource exploitation by red deer, Cervus elaphus (Lovari et al, 2014;Ferretti et al, 2015), have been suggested as factors underlying pasture depletion, with subsequent negative effects on population dynamics.…”

Section: Introductionmentioning

confidence: 99%

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Being “hangry”: food depletion and its cascading effects on social behaviour

Fattorini

Brunetti

Baruzzi

et al. 2018

Biological Journal of the Linnean Society

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Evolutionary theory suggests two alternative ways in which competitive interactions could vary in response to different levels of food abundance. Competition theory suggests that aggression should be greater when resource availability is lower, as an evolutionary stable strategy to access food. Alternatively, energy allocated to aggressive interactions should increase when the available spectrum of food resources is wider, in turn allowing a greater selec-tion. We tested these hypotheses on a group-living herbivore, the Apennine chamois, Rupicapra pyrenaica ornata. We compared social, aggressive and vigilance behaviour and relevant endocrine correlates across three areas: two 'poorer' areas, i.e. with a lower availability of nutritious pasture, and a 'richer' one. In the richer area, we observed: (1) the largest group size/greatest proportion of young individuals in groups; (2) the lowest rate/intensity of aggression between individuals, at feeding; (3) the lowest duration of vigilance and proportion of 'costly' vigilance, i.e. postures performed without chewing food; and (4) the lowest levels of testosterone and cortisol metabolites, suggesting a lower endogenous aggressiveness/stress response. Our findings agree with the competition theory, suggesting a role of food depletion in increasing aggression between foraging individuals, as an evolutionary stable strategy, with cascading effects on group phenology, vigilance and stress.

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Section: Study Areas and Populationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Being “hangry”: food depletion and its cascading effects on social behaviour

Fattorini

Brunetti

Baruzzi

et al. 2018

Biological Journal of the Linnean Society

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“…For example, red deer may trigger habitat segregation in chamois (Anderwald et al ., ). Furthermore, negative effects of the use of grasslands by red deer at high density on the demography of the closely related Apennine chamois Rupicapra pyrenaica ornata were observed (Ferretti et al ., ). In addition, none of the alternative hypotheses – namely that the chamois numeric decline would favour the increase in red deer, and that growth rates of both populations are independent from the population size of the other species – was consistent with the observed patterns.…”

Section: Discussionmentioning

confidence: 97%

“…This pattern is suggestive of a negative impact of red deer on chamois (cf. Ferretti, Lovari & Stephens, 2019). The need to consider alternative explanatory hypotheses, however, is crucial to causal inference (Rutter, 2007).…”

Section: Introductionmentioning

confidence: 99%

“…density, climate), and evaluate the consistency of alternatives causal structures that may explain the contrasting population dynamics. Available knowledge on chamois-red deer relationships (Lovari et al, 2014;Anderwald et al, 2015;Ferretti et al, 2015Ferretti et al, , 2019Anderwald, Haller & Filli, 2016) suggests that H1 should be supported over H3, with H2 being the least plausible hypothesis.…”

Section: Introductionmentioning

confidence: 99%

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Long‐term dynamics of Alpine ungulates suggest interspecific competition

et al. 2019

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Studies identifying interspecific competition require the investigation of negative long‐term effects between sympatric species showing overlap in resource use. A potential for competition exists between red deer Cervus elaphus and chamois Rupicapra spp., as revealed by the high dietary overlap observed throughout the range where the species co‐occur. Furthermore, some studies have recently reported negative demographic consequences on chamois populations living in sympatry with red deer. Using time series of counts spanning 35 years between 1984 and 2018 in the Stelvio National Park (Central Italian Alps), we tested for density dependence using state‐space models and explored the evidence of competitive interaction through Ricker‐like models on the growth rate of both species. We contrasted alternative hypotheses for the processes explaining the trends of (decreasing) chamois and (increasing) red deer populations. We expected chamois dynamics to be negatively affected by increasing deer abundance, while deer dynamics should be primarily affected by climate forcing and density dependence. We found evidence that resources were limiting for both species. In particular, growth rates were negatively affected by the synergistic effect of winter weather conditions and density dependence. The most important variable limiting the chamois population, however, was the increase in red deer numbers. The dynamics of this species was unaffected by chamois numbers. While causality cannot be inferred from the data, these results are consistent with the hypothesis of a negative effect of red deer on chamois dynamics, thus supporting the occurrence of interference or exploitation competition between sympatric mountain‐dwelling ungulates. Understanding the processes underlying temporal dynamics is pivotal for informed management of wildlife. Consequences of interspecific competition should be carefully evaluated where the populations of the weaker competitor are of conservation concern, especially in the light of the negative effects of anthropogenic environmental change on animal populations.

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Disentangling demographic effects of red deer on chamois population dynamics

Donini

Pedrotti

Ferretti

et al. 2021

Ecology and Evolution

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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.

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Joint effects of weather and interspecific competition on foraging behavior and survival of a mountain herbivore

Cited by 19 publications

References 77 publications

Being “hangry”: food depletion and its cascading effects on social behaviour

Being “hangry”: food depletion and its cascading effects on social behaviour

Long‐term dynamics of Alpine ungulates suggest interspecific competition

Disentangling demographic effects of red deer on chamois population dynamics

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