Animal home range use is a central focus of ecological research. However, how and why home range size varies between individuals is not well studied or understood for most species. We develop a hierarchical analytical approach--using generalized linear mixed-effects modeling of time series of home range sizes--that allows variance in home range size to be decomposed into components due to variation in temporal, spatial, and individual-level processes, also facilitating intra- and interspecific comparative analyses. We applied the approach to data from a roe deer population radiotracked in central Italy. Over multiple timescales, temporal variation is explained by photoperiod and climate and spatial variation by the distribution of habitat types and spatial variance in radiotracking error. Differences between individuals explained a substantial amount of variance in home range size, but only a relatively minor part was explained by the individual attributes of sex and age. We conclude that the choice of temporal scale at which data are collected and the definition of home range can significantly influence biological inference. We suggest that the appropriate choice of scale and definition requires a good understanding of the ecology and life history of the study species. Our findings contrast with several common assumptions about roe deer behavior.

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Wildlife management systems face growing challenges to cope with increasingly complex interactions between wildlife populations, the environment and human activities. In this position statement, we address the most important issues characterising current ungulate conservation and management in Europe. We present some key points arising from ecological research that may be critical for a reassessment of ungulate management in the future.

Reintroductions are commonly used to restore the local biological diversity and/or save threatened taxa. In human-altered landscapes, we may expect that reintroduced species affect taxa already present. In Abruzzo, Lazio and Molise National Park (central Apennines, Italy), a 30% decline in the abundance of 'vulnerable' Apennine chamois (2005: c. 650 individuals, 2010: c. 450 individuals) has been recorded, whereas red deer (reintroduced in 1972-1987: 81 individuals) have greatly increased (2010: > 2500 individuals). We investigated space and diet overlaps between red deer and Apennine chamois, and their effects on foraging behaviour of the latter. We also compared the composition of grasslands with that recorded when the former were absent. In 2010-2011, we found out: (1) a great space (> 75%) and diet (> 90%) overlap between deer and chamois; (2) a significant increase of unpalatable plant species and a decreasing trend of the nutritious, most grazed species by chamois, in respect to when deer were absent; (3) irrespective from vegetation type, a significantly reduced bite rate of adult female chamois in patches used also by deer, compared with areas without deer. Our results suggest a negative effect of red deer on the availability of nutritious plant species in summer-autumn, possibly because of grazing and physical damage on the grassland caused by trampling. Environmental conditions and access to high-quality forage in the warm season influence the winter survival of offspring of mountain ungulates. Our results indicate that interspecific overlap in resource use with an increasing, reintroduced population can threaten rare taxa. Reintroductions of potentially competing species should be avoided in areas where populations of threatened taxa exist.Competition between reintroduced red deer and Apennine chamois S. Lovari et al. Supporting informationAdditional Supporting Information may be found in the online version of this article at the publisher's web-site:Appendix S1. Supplementary online material.Competition between reintroduced red deer and Apennine chamois S. Lovari et al.

Interference is expected to occur at feeding areas between species with a similar diet, but few studies have tested this idea for wild ungulates. We analysed interactions between fallow deer, European roe deer and wild boar, in three sites, in a Mediterranean area. We expected that interference should be greater between deer than between them and wild boar. We documented the negative effects of behavioural interference by fallow on foraging behaviour of roe deer, under field conditions. Deer species built up 90% interference interactions, with fallow always dominant on roe, also through direct aggression. Although roe deer decreased feeding and increased vigilance levels in proximity (< 50 m) of either fallow deer or wild boar, they were displaced significantly more often by the former than by the latter. Fallow deer were neither displaced nor alarmed by roe and rarely by wild boar. No deer species displaced wild boar. Interference was significantly greater on solitary roe deer, especially females, in spring and roe left the feeding ground most often in the smallest site (13 ha). Roe deer avoided areas where the local density of fallow deer was the highest. During our 4-year-study, roe deer density decreased whereas fallow deer numbers increased. Behavioural interference may explain how fallow deer outcompete roe deer through spatial exclusion from feeding sites and avoidance of areas with high densities of the former. Fallow deer evolved in semi-arid, relatively poor habitats of Asia Minor: interspecific defence of crucial resources could have developed as a beneficial tactic for its survival