Feeding ecology of alpine chamois living in sympatry with other ruminant species

Abstract

The populations of Alpine chamois Rupicapra rupicapra rupicapra are currently not at risk of extinction, but local population declines have been observed in some areas. Competition with other herbivore species may be one of the causes for this decline. The present research aims at describing the autumnal diet and preferences of Alpine chamois living in sympatry with red deer Cervus elaphus and roe deer Capreolus capreolus in central Italian Alps and to verify the presence of spatial and diet overlap among these herbivore species. We analyzed the rumen content of 35 samples collected during the hunting season from animals culled in Val Fontana. The results were integrated by data previously collected on rumen content of red deer and roe deer and on space use of the three herbivore species in the same study area. We identified 26 species and 15 genera belonging to 21 plant families of the 51 available in the study area. Monocotyledon families were the most frequently represented in chamois diet composition (78.11%), followed by Ericaceae (5.30%), Betulaceae (4.32%) and Cupressaceae (3.37%). All results showed similar diet between genders. Chamois diet was more similar to red deer than to roe deer diet. The diet selection index (W) showed that on the east-facing side of the valley some species (Calluna vulgaris: W m  5.27; Juniperus communis: W m  4.24; Loiseleuria procumbens: W m  4.82) were selected above their availability, perhaps as a consequence of the higher spatial overlap on this side between chamois and red deer, which make similar use of vegetal resources. Although competition among species is unlikely, due to the low population densities, over-exploitation of food resources and food niche overlap may be future limiting factors for local chamois population, and they should be taken into account for the proper management and control of wild and domestic ruminants.

Seasonal diet composition of Pyrenean chamois is mainly shaped by primary production waves

“…The detection of 39 different plants in the chamois diet is within the range of other studies using the same methodology [27,29,38,71,72]. A study using DNA barcoding [30], on the other hand, showed that chamois can consume up to 110 different species.…”

“…Except from May to August, this perennial dwarf-shrub is the plant most consumed by Pyrenean chamois in our area. The consumption of this plant is not new as it has been detected in the diet of chamois from the Cantabrian Mountains to the Italian central Alps [29,30,85]. In other areas, it even provides a permanent food source for red grouse [86] and red deer [87].…”

“…Winter diets, on the other hand, compensate for the high locomotion and thermoregulation costs in snowy landscapes [24,25]. Considerable research effort has been directed towards summer [26–28] and autumn diets [29,30], whereas information on the spring and winter feeding behaviours of chamois is practically non-existent.…”

Long‐term dynamics of Alpine ungulates suggest interspecific competition

“…These include clear evidence of habitat overlap, diet overlap, and limiting shared dietary resources (de Boer & Prins, ). Although our study does not provide direct evidence for dietary overlap in the study area, red deer and chamois are both intermediate feeders (Hofmann, ), and several studies found strong dietary overlap throughout the range where the two species co‐occur (Czech Republic: Homolka & Heroldová, ; Western Italian Alps: Bertolino et al ., ; French Alps: Redjadj et al ., ; Central Italian Alps: Andreoli et al ., ). Furthermore, our analysis showed that density dependence played a key role in regulating population size of red deer and chamois in our study area, providing evidence that resources are limiting in these populations.…”

“…In mountainous areas where they live in sympatry, red deer Cervus elaphus and chamois Rupicapra spp. show strong dietary overlap, indicating the potential for competition (Homolka & Heroldov a, 2001;Bertolino, Di Montezemolo & Bassano, 2009;Lovari et al, 2014;Redjadj et al, 2014;Andreoli et al, 2016). The long-term monitoring of the coupled dynamics of red deer and Alpine chamois Rupicapra rupicapra rupicapra within the Stelvio National Park (Central Italian Alps) offers the rare opportunity to investigate the demographic effects of sympatry between these species.…”