Do the sexes tend to segregate in roe deer in agricultural environments? An analysis of group composition

Villerette, Nicolas; Marchal, Carole; Pays, Olivier; Delorme, Daniel; Gerard, Jean-François

doi:10.1139/z06-052

Cited by 10 publications

(4 citation statements)

References 28 publications

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“…135 In roe deer, home ranges of adult males and females overlap all year 136 and mixed-sex groups can be common all year, particularly outside of the period when some males establish breeding territories. 136,137 In huemul (Hippocamelus bisulcus), adult males and females can overlap all year, [138][139][140] but single-sex groups are common. Males were commonly seen alone, or as groups averaging 2.5 individuals, while female groups averaged 2.9 individuals.…”

Section: Variation In Social Organisation and Behaviour Sexual And Somentioning

confidence: 99%

Intraspecific variation in biology and ecology of deer: magnitude and causation

Putman¹,

Flueck

2011

Anim. Prod. Sci.

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It has been noted that the search for patterns in biology to assist our understanding, often leads to over-simplification. That is, we are satisfied with statements that ‘the species as a rule does this’ or, ‘males of this species do that’. But within such generalisations are masked what are often important variations from that supposed norm and in practice there is tremendous variation in morphology, physiology, social organisation and behaviour of any one species. The focus on a supposedly mean optimal phenotype has diverted attention away from variation around that mean, which is regularly regarded as a kind of ‘noise’ stemming merely from stochastic effects, and thus irrelevant to evolution. Yet it is becoming increasingly clear that this variation is by converse extremely significant and of tremendous importance both to evolutionary biologists and to managers. Such intraspecific variation (IV) may be directly due to underlying genetic differences between individuals or populations within a species, but equally may include a degree of phenotypic plasticity whether as ‘non-labile’, traits which are expressed once in an individual’s lifetime, as fixed characteristics inherited from the parents or as more labile traits which are expressed repeatedly and reversibly in a mature individual according to prevailing conditions. Recognition of the extraordinary degree of IV which may be recorded within species has important consequences for management of cervids and conservation of threatened species. We review the extent of IV in diet, in morphology, mature bodyweight, reproductive physiology, in population demography and structure (sex ratio, fecundity, frequency of reproduction) before also reviewing the striking variation to be observed in behaviour: differences between individuals or populations in ranging behaviour, migratory tendency, differences in social and sexual organisation. In each case we explore the factors which may underlie the variation observed, considering the extent to which variation described has a primarily genetic basis or is a more plastic response to more immediate social and ecological cues.

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Section: Variation In Social Organisation and Behaviour Sexual And Somentioning

confidence: 99%

Intraspecific variation in biology and ecology of deer: magnitude and causation

Putman¹,

Flueck

2011

Anim. Prod. Sci.

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“…As is usually reported for European roe deer, group size was greatest in winter, when adult males are not territorial and the young of the year are fully mobile [49]. Winter groupings were larger than generally reported in forested landscapes, as is typically the case in open cultivated plains [50]–[52].…”

Section: Methodsmentioning

confidence: 85%

Group Dynamics and Landscape Features Constrain the Exploration of Herds in Fusion-Fission Societies: The Case of European Roe Deer

et al. 2012

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Despite the large number of movement studies, the constraints that grouping imposes on movement decisions remain essentially unexplored, even for highly social species. Such constraints could be key, however, to understanding the dynamics and spatial organisation of species living in group fusion-fission systems. We investigated the winter movements (speed and diffusion coefficient) of groups of free-ranging roe deer ( Capreolus capreolus ), in an agricultural landscape characterised by a mosaic of food and foodless patches. Most groups were short-lived units that merged and split up frequently during the course of a day. Deer groups decreased their speed and diffusion rate in areas where food patches were abundant, as well as when travelling close to main roads and crest lines and far from forests. While accounting for these behavioural adjustments to habitat features, our study revealed some constraints imposed by group foraging: large groups reached the limit of their diffusion rate faster than small groups. The ability of individuals to move rapidly to new foraging locations following patch depression thus decreases with group size. Our results highlight the importance of considering both habitat heterogeneity and group dynamics when predicting the movements of individuals in group fusion-fission societies. Further, we provide empirical evidence that group cohesion can restrain movement and, therefore, the speed at which group members can explore their environment. When maintaining cohesion reduces foraging gains because of movement constraints, leaving the group may become a fitness-rewarding decision, especially when individuals can join other groups located nearby, which would tend to maintain highly dynamical group fusion-fission systems. Our findings also provide the basis for new hypotheses explaining a broad range of ecological patterns, such as the broader diet and longer residency time reported for larger herbivore groups.

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“…Although the roe deer is a rather solitary forest-dwelling herbivore, individuals become gregarious foragers in open habitats during winter, forming non-permanent groups with short lifetimes, such that an individual generally experiences multiple fission-fusion events within a single day [38]. In winter, mixed-sex groups are generally over-represented, as adult males are no longer territorial [39]. We assessed the immediate changes in exploration capacity (i.e., extensive search mode characteristics) through variations in mean group speed (MGS) and an index of net displacement rate (NDR) over the two moves that preceded and followed fission events.…”

Section: Introductionmentioning

confidence: 99%

Increased Exploration Capacity Promotes Group Fission in Gregarious Foraging Herbivores

Lardy¹,

Fortin²,

Pays³

2016

PLoS ONE

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Many gregarious species display rapid fission-fusion dynamics with individuals frequently leaving their groups to reunite or to form new ones soon after. The adaptive value of such ephemeral associations might reflect a frequent tilt in the balance between the costs and benefits of maintaining group cohesion. The lack of information on the short-term advantages of group fission, however, hampers our understanding of group dynamics. We investigated the effect of group fission on area-restricted search, a search tactic that is commonly used when food distribution is spatially autocorrelated. Specifically, we determine if roe deer (Capreolus capreolus) improve key aspects of their extensive search mode immediately after fission. We found that groups indeed moved faster and farther over time immediately after than before fission. This gain was highest for the smallest group that resulted from fission, which was more likely to include the fission’s initiator. Sex of group members further mediated the immediate gain in search capacity, as post-fission groups moved away at farthest rate when they were only comprised of males. Our study suggests that social conflicts during the extensive search mode can promote group fission and, as such, can be a key determinant of group fission-fusion dynamics that are commonly observed in gregarious herbivores.

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Do the sexes tend to segregate in roe deer in agricultural environments? An analysis of group composition

Cited by 10 publications

References 28 publications

Intraspecific variation in biology and ecology of deer: magnitude and causation

Intraspecific variation in biology and ecology of deer: magnitude and causation

Group Dynamics and Landscape Features Constrain the Exploration of Herds in Fusion-Fission Societies: The Case of European Roe Deer

Increased Exploration Capacity Promotes Group Fission in Gregarious Foraging Herbivores

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