Family Effects on Growth and Survival of Juvenile Roe Deer

Abstract

This paper reports evidence for family effects (i.e., nonindependence between siblings) on components of juvenile fitness in two high‐performance populations of roe deer (Capreolus capreolus). In Trois Fontaines (eastern France), 51 sets of twins were ear‐tagged as newborns and then intensively monitored until adulthood (to ≥4 yr of age). On the island of Storfosna (central western Norway), 79 sets of twins and 40 sets of triplets were radiotracked from birth to ≥1 mo of age. In both populations, family effects were observed for measures of early body development and winter body mass. Measurements for sibling fawns were more similar than the same measures for nonsiblings. During unfavorable years (i.e., poor deer survival in summer or high population density), sibling fawns survived or died together much more often than expected by chance. Conversely, during favorable years (i.e., high fawn survival or low density), there was no evidence for family effects on survival of either twins or triplets. These results demonstrate that family effects on juvenile fitness of roe deer are pervasive, and that family effects on early survival differ among years. To assess the consequences of family effects on population dynamics, we tested the model of . This model proposes that family effects should cause increased variance in recruitment among females. Consistent with this model, family effects led to a threefold increase in the variance of total reproductive success over 5 yr of 37 females in Trois Fontaines. Data from Storfosna (11 females monitored for 3 yr) also supported Crow and Morton’s model. Ultimately, family effects in polytocous species could reduce the intensity of sexual selection and modify the genetic structure of populations.

Spatial patterns and density dependence in the dynamics of a roe deer (Capreolus capreolus) population in central Italy

“…In our case the choice to analyse Collinaccia and Monti data separately was quite natural due to the topography of the study area. Gaillard et al (1998a) showed that there are differences of growth and survival at the family level, i.e. at a scale of "one home range", while the differences described by this work referred to a larger spatial scale of "several home ranges".…”

“…Despite the fact that in roe deer a sex-biased fawn survival was not observed (Gaillard et al 1998c), the impact of fox predation seems to be larger on male than on female fawns (Aanes and Andersen 1996). Since in our study area both wolves and foxes are widely present, we expect first, that fawn survival should be lower than in other populations without large predators such as Chizé in France (Gaillard et al 1993, Storfosna in Norway (Gaillard et al 1998a) or in the Swabian mountains in Germany (Thor 1994) and second, that males should suffer lower survival when compared with female fawns. So we specifically tested whether, for fawns, male survival was lower than female survival.…”

Fitness consequences of environmental conditions at different life stages in a long-lived vertebrate

“…We considered reproductive and survival characteristics of prime-aged females (2-8 years) before senescence; these parameters do not vary with age in prime-aged females [36,37]. We divided annual reproductive success into three categories: (i) 'no offspring weaned', (ii) 'one offspring weaned' and (iii) 'two or three offspring weaned' [38].…”

Survival rates and causes of mortality of roe deer Capreolus capreolus in a rural landscape, eastern Poland

“…Therefore, human harvest is an important mortality factor in managed deer populations (Langvatn and Loison 1999). In addition to hunting, natural causes of mortality such as predation (Okarma et al 1995;Aanes and Andersen 1996;Melis et al 2009), climatic factors (Gaillard et al 1993;Gaillard et al 1998), male-male interaction and diseases (Aguirre et al 1999) occur and vary between age classes and sexes . These factors may act differently at various levels of deer population densities and resource availability (Pettorelli et al 2003).…”