Pasture Quality Affects Juvenile Survival through Reduced Maternal Care in a Mountain‐Dwelling Ungulate

Abstract

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

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

“…All of this emphasizes why we would expect the bite rate to be lower in the deer-present site than in the deer-free one. Overall, the quantity and intensity of maternal care provided to offspring would be affected, decreasing the winter survival of chamois kids ( Scornavacca et al. 2016 ).…”

“…Food depletion and/or reduced access to high-quality forage during nursing/weaning will limit maternal investment; this can lead to short-term negative effects on offspring growth and survival (e.g., Festa-Bianchet and Jorgenson 1997 ; Therrien et al. 2008 ; Scornavacca et al. 2016 ), and/or long-term reductions in body size, phenotypic quality, and reproductive success ( Festa-Bianchet et al.…”

Different effects of alpine woody plant expansion on domestic and wild ungulates

“…However, the phenotypic capacity of chamois could allow them to consume more woody plants than observed in our study area but further studies would be necessary to assess the effect of these dietary adaptations on the performance of this species. At the same time, this study focussed on summer and autumn diets of chamois because there are key for the reproduction and survival of the species (Garel et al, ; Scornavacca et al, ). Food availability during winter may also determine chamois survival, but there is no information on that process.…”

Horn size and nutrition in mountain sheep: Can ewe handle the truth?

“…In seasonal and unpredictable environments, where food availability can fluctuate, females should ensure that they retain sufficient body reserves to survive food‐limited periods by reducing reproductive output accordingly (Therrien et al , Bårdsen et al ). When maternal nutrition is compromised, young are smaller at birth (Keech et al , Monteith et al ), nursing and maternal care decline (Rachlow and Bowyer , Therrien et al , Scornavacca et al ), growth of young is suppressed (Festa‐Bianchet and Jorgenson , Martin and Festa‐Bianchet , Tollefson et al ), and mortality of young increases (Therrien et al , Monteith et al , Scornavacca et al ). This conservative life‐history strategy transfers the costs of reproduction from females to their young (Festa‐Bianchet and Jorgenson , Martin and Festa‐Bianchet , Monteith et al ).…”