Legislative hurdles to using traditional domestic livestock in rewilding programmes in Europe.

Rewilding is a restoration strategy that aims to return anthropogenic ecosystems to a "self-organized" state, by reinstating trophic complexity through disturbance (e.g. predation, herbivory), dispersal and connectivity. In depopulated areas of Europe, lite versions of rewilding, that maintain but minimize the management of rewilding species (e.g. predators, large herbivores) is gaining support. Livestock rewilding (LR) is a form of rewilding-lite, that uses livestock landraces as keystone species in the restoration of herbivory (the functional integrity of ecosystems) offering ecosystem services, such as ecotourism and the sale of livestock population surpluses, that can mitigate the economic and social effects of rural depopulation. Many challenges remain to implementing LR, including (i) more empirical evidence is required of the feasibility of LR across a variety of habitats and conditions, and (ii) understanding the hurdles that legislation poses for LR, the latter being the aim of this study. To accomplish this, we reviewed the EU legislation on environmental protection, animal health and welfare, identification and traceability, and ownership and civil responsibility, to assess how this might apply to LR. Although there is no specific EU legislation prohibiting LR, the review indicates that it is not clear what legislation applies to LR, as LR's status lies between that of livestock and wild species. As such the existing legislation can be a serious impediment to the development of LR programmes. We highlight the needs for a legal definition, and status of LR species and their ownership. We propose ways to adapt this legislation to support the application of LR programmes in abandoned areas of EU, for example, by using legal exceptions intended for livestock under extensive animal farming systems.

The impact of past introductions on an iconic and economically important species, the red deer of Scotland.

The red deer (Cervus elaphus) is an iconic species in Scotland and, due to its value as a game species, an important element of the Scottish rural economy. The native status of this species is sometimes questioned because of many recorded introductions of nonnative deer in the past that were an attempt to improve trophy size. In this study, we assessed the impact of past introductions on the genetic makeup of Scottish red deer by genotyping at 15 microsatellite loci a large number of samples (n = 1152), including mainland and island Scottish red deer and individuals from several putative external source populations used in introductions to improve trophy size. Population structure and introgression assessment analyses revealed that the impact of introductions was weak in Highland red deer populations but more prominent on the islands, especially on those where current red deer populations are mostly or entirely derived from introductions (Harris & Lewis, Arran, and Rum). Frequent imports of Central-Eastern European red deer into English deer parks were reflected in the higher genetic introgression values found in some of the individuals collected in parks.

Evidence for coevolution of sociality and relative brain size in three orders of mammals.

As the brain is responsible for managing an individual's behavioral response to its environment, we should expect that large relative brain size is an evolutionary response to cognitively challenging behaviors. The "social brain hypothesis" argues that maintaining group cohesion is cognitively demanding as individuals living in groups need to be able to resolve conflicts that impact on their ability to meet resource requirements. If sociality does impose cognitive demands, we expect changes in relative brain size and sociality to be coupled over evolutionary time. In this study, we analyze data on sociality and relative brain size for 206 species of ungulates, carnivores, and primates and provide, for the first time, evidence that changes in sociality and relative brain size are closely correlated over evolutionary time for all three mammalian orders. This suggests a process of coevolution and provides support for the social brain theory. However, differences between taxonomic orders in the stability of the transition between small-brained/nonsocial and large-brained/social imply that, although sociality is cognitively demanding, sociality and relative brain size can become decoupled in some cases. Carnivores seem to have been especially prone to this.

Sexual selection and senescence: male size-dimorphic ungulates evolved relatively smaller molars than females.

As a general rule, males of sexually dimorphic ungulate species have evolved larger body size than females but shorter reproductive life spans as elements of their strategy for intrasexual competition for mating opportunities. Evolutionary theories of senescence predict that the durability of somatic structures should relate to the length of reproductive life span. This prediction has recently been tested for red deer (Cervus elaphus): molariform teeth of males are smaller and less durable than those of females, which corresponds with sex differences in reproductive life span. However, general evidence that male teeth are smaller than expected by allometric rules as a consequence of sexual selection for increasing male body mass requires an interspecific comparison between dimorphic and nondimorphic ungulates. Here we investigate the relationship between cheek-teeth size (occlusal surface area; OSA) and body mass in 123 species of extant ungulates. We found lower slopes for dimorphic species compared with nondimorphic ones and smaller OSA, relative to body mass, in males of dimorphic species compared with females of dimorphic species. Rates of evolution of OSA relative to rates of evolution of body mass were greater in females than in males and also greater in nondimorphic than in dimorphic species. Our results are consistent with the hypothesis that sexual selection in polygynous male ungulates favors body size more than tooth size, with possible consequences in male senescence via early depletion of male teeth compared to females.

Gregariousness increases brain size in ungulates.

The brain's main function is to organise the physiological and behavioural responses to environmental and social challenges in order to keep the organism alive. Here, we studied the effects that gregariousness (as a measurement of sociality), dietary habits, gestation length and sex have on brain size of extant ungulates. The analysis controlled for the effects of phylogeny and for random variability implicit in the data set. We tested the following groups of hypotheses: (1) Social brain hypothesis-gregarious species are more likely to have larger brains than non-gregarious species because the former are subjected to demanding and complex social interactions; (2) Ecological hypothesis-dietary habits impose challenging cognitive tasks associated with finding and manipulating food (foraging strategy); (3) Developmental hypotheses (a) energy strategy: selection for larger brains operates, primarily, on maternal metabolic turnover (i.e. gestation length) in relation to food quality because the majority of the brain's growth takes place in utero, and finally (b) sex hypothesis: females are expected to have larger brains than males, relative to body size, because of the differential growth rates of the soma and brain between the sexes. We found that, after adjusting for body mass, gregariousness and gestation length explained most of the variation in brain mass across the ungulate species studied. Larger species had larger brains; gregarious species and those with longer gestation lengths, relative to body mass, had larger brains than non-gregarious species and those with shorter gestation lengths. The effect of diet was negligible and subrogated by gestation length, and sex had no significant effect on brain size. The ultimate cause that could have triggered the co-evolution between gestation length and brain size remains unclear.

The effect of season, sex and feeding style on home range area versus body mass scaling in temperate ruminants.

Sex-specific estimates of the summer and winter home range area of 19 species of temperate ruminants were collated from the literature. It was predicted that there should be a shallower slope for the home range area against body mass relationship during winter than during summer, as large ruminants can meet more of their energy requirements from the fat reserves deposited during summer than small ruminants. Consequently, relatively large species do not need to range as widely during winter. There was a significant positive relationship between body mass and summer and winter home range area in both females and males. This relationship remained significant when analysed within feeding styles (browser, mixed feeder, grazer), except in mixed feeders in winter. As predicted, slope estimates were significantly lower during winter (b=0.59) than during summer (b=1.28), both before and after controlling for phylogeny. After controlling for phylogeny, browsers had a steeper slope (summer: b=1.48; winter: b=1.07) of the home range area against body mass relationship than did mixed feeders (summer: b=0.75; winter: b=-0.11) or grazers (summer: b=1.10; winter: b=0.34). There was no effect of sex after body mass was controlled for. The effect of season, sex and feeding style on the home range area versus body mass relationship in temperate ruminants is discussed.

The functional relationship between feeding type and jaw and cranial morphology in ungulates.

The relationship between jaw and skull morphology and feeding type (grazer, mixed feeder, browser, frugivorous, omnivorous) was analysed in 94 species of extant ungulates. A total of 21 morphological traits of the jaw and skull (17 and 4, respectively) were analysed using analysis of covariance, with body mass as covariate. To take into account the phylogenetic effect, simulations were generated under the Brownian motion model of character evolution. Analysis of covariance was applied to these simulations and the simulated F-ratios were used to assess the signification of the F-ratios for the real values of the traits. The feeding types had a weak effect on ungulate cranial and jaw morphology in comparison with the phylogenetic effect, since, before phylogeny correction, the analysis of covariance showed statistically significant differences associated with feeding type in 15 out of the 21 traits analysed. After controlling for phylogeny, only 2 significant traits remained, the length of the coronoid process and the occipital height. Omnivorous species had shorter coronoid processes than grazers or mixed feeders, and the occipital height was greater in the omnivorous species than in the grazers, mixed feeders or browsers. The coronoid process is involved in the generation of bite force, being the effective moment arm of the temporalis muscle, and occipital height is positively related to the force exerted by the temporalis muscle. This result matches the hypothesis that species with a toughness diet should show higher bite force ("toughness" describes the resistance of a material to being mechanically broken down). When the omnivorous species were excluded from the analysis, no differences in jaw and skull morphology were detected between the rest of the feeding types.

The relative roles of phylogeny, body size and feeding style on the activity time of temperate ruminants: a reanalysis.

In 1998, A. Mysterud analysed the relationships between a behavioural parameter (activity time, AT) and body mass and feeding style for 18 temperate ruminants. He found a negative allometric relationship between body mass and AT, and also found a significant effect of feeding style on AT after controlling for body mass. We reanalysed this data set taking into account the effect of phylogeny, and found that while body mass and AT were negatively related, feeding style did not have any effect on AT. We discuss the strong effect that phylogeny has on morphophysiological and behavioural features of ruminants that differ in feeding style, and the lack of evidence to support a feeding style effect.