Are mouflon Ovis gmelini musimon really grazers? A review of variation in diet composition

Was the steppe bison a grazing beast in Pleistocene landscapes?

The history and palaeoecology of the steppe bison (Bison priscus) remain incompletely understood despite its widespread distribution. Using dental microwear textural analysis (DMTA) and vegetation modelling, we reconstructed the diet and assessed the habitat of steppe bison inhabiting Eurasia and Alaska since the Middle Pleistocene. During the Late Pleistocene, steppe bison occupied a variety of biome types: from the mosaic of temperate summergreen forest and steppe/temperate grassland (Serbia) to the tundra biomes (Siberia and Alaska). Despite the differences in the identified biome types, the diet of steppe bison did not differ significantly among populations in Eurasia. DMTA classified it as a mixed forager in all populations studied. The DMTA of Bb1 bison-a recently identified genetically extinct sister-clade of Bison bonasus-was typical of a highly grazing bovid species and differed from all B. priscus populations. The results of the study temper the common perception that steppe bison were grazers in steppe habitats. The dietary plasticity of the steppe bison was lower when compared with modern European bison and may have played an important role in its extinction, even in the stable tundra biome of eastern Siberia, where it has survived the longest in all of Eurasia.

Epipalaeolithic animal tending to Neolithic herding at Abu Hureyra, Syria (12,800–7,800 calBP): Deciphering dung spherulites

Excavations at Abu Hureyra, Syria, during the 1970s exposed a long sequence of occupation spanning the transition from hunting-and-gathering to agriculture. Dung spherulites preserved within curated flotation samples from Epipalaeolithic (ca. 13,300–11,400 calBP) and Neolithic (ca. 10,600–7,800 calBP) occupations are examined here alongside archaeological, archaeobotanical, and zooarchaeological data to consider animal management, fuel selection, and various uses of dung. Spherulites were present throughout the entire sequence in varying concentrations. Using a new method to quantify spherulites, exclusion criteria were developed to eliminate samples possibly contaminated with modern dung, strengthening observations of ancient human behavior. Darkened spherulites within an Epipalaeolithic 1B firepit (12,800–12,300 calBP) indicate burning between 500–700°C, documenting early use of dung fuel by hunter-gatherers as a supplement to wood, coeval with a dramatic shift to rectilinear architecture, increasing proportions of wild sheep and aurochsen, reduced emphasis on small game, and elevated dung concentrations immediately outside the 1B dwelling. Combined, these observations suggest that small numbers of live animals (possibly wild sheep) were tended on-site by Epipalaeolithic hunter-gatherers to supplement gazelle hunting, raising the question of whether early experiments in animal management emerged contemporaneously with, or pre-date, cultivation. Dung was used to prepare plaster floors during the Neolithic and continued to be burned as a supplemental fuel, indicating that spherulites were deposited via multiple human- and animal-related pathways. This has important implications for interpretations of archaeobotanical assemblages across the region. Spherulite concentrations dropped abruptly during Neolithic 2B (9,300–8,000 calBP) and 2C (8,000–7,800 calBP), when sheep/goat herding surpassed gazelle hunting, possibly corresponding with movement of animals away from the site as herd sizes increased. As hunter-gatherers at Abu Hureyra began interacting with wild taxa in different ways, they set in motion a remarkable transformation in the ways people interacted with animals, plants, and their environment.

Livestock displace European mouflon from optimal foraging sites

The conflict between free-ranging livestock and wildlife is a serious conservation concern across rural communities worldwide. Livestock may affect wild herbivores via direct competition for resources due to spatial and diet overlap or via behavioural interference. It is imperative that we disentangle the effects of livestock on wildlife behaviour to obtain an empirical basis able to stir management and conservation decisions. Here, we studied the effect of livestock presence on the habitat selection in a free-ranging European mouflon (Ovis aries musimon) population in Sardinia, where the species is under strict protection. We collected spatial data on mouflon and livestock during two consecutive years to investigate whether the mouflon selection of key feeding grassland sites was negatively impacted by the livestock presence. We found that mouflon preferably selected grassland, and its selection significantly increased when grass was of better quality (greener). We showed that livestock presence led to the displacement of mouflon from such preferred feeding sites, an effect clearly exacerbated by livestock proximity. We indeed found that the selection of grassland by mouflon dropped significantly when the distance between livestock and mouflon was below ~ 650 m, providing a useful management threshold indication. Livestock presence in close proximity displaced mouflon to sub-optimal habitat, and its effects may have negative impact on the population dynamic of this species which is already characterized by low female productivity within harsh Mediterranean environment. Our results give clear management indications aimed at better managing livestock grazing within natural areas to ultimately improve wildlife conservation.

Physical characteristics of forestomach contents from two nondomestic small ruminants, the blackbuck (Antilope cervicapra) and the Arabian sand gazelle (Gazella subgutturosa marica)

Rumen content stratification and the degree of dissociation of particle and fluid retention in the reticulorumen differ between 'moose-type' and 'cattle-type' ruminant species. These differences are not strictly linked to diet, except for a seeming limitation of 'moose-type' ruminants to a browsing niche. Nevertheless, these differences can be plausibly linked to other observed differences in ruminants, such as the intraruminal papillation pattern, or the size of the omasum. However, many of the corresponding measures are still only available for a restricted number of species. Here, we investigated the dry matter (i.e., the inverse of the moisture) concentration in forestomach contents of 10 blackbuck (Antilope cervicapra) and 7 Arabian sand gazelle (Gazella subgutturosa marica), and quantified the rumen papillation pattern. The blackbucks had distinct rumen contents stratification, with more moisture in ventral than in dorsal contents (difference 3.6% units, P < 0.001), whereas this difference was much less pronounced in the sand gazelles (0.6% units, P = 0.227). While reticulum contents were particularly moist in both species, omasum contents were particularly dry in sand gazelles, but did not differ in moisture from rumen contents in the blackbuck. This species is an outlier among ruminants due to its extremely small omasum. The intraruminal papillation pattern did not differ between blackbucks and sand gazelles and showed a surface enlargement factor (SEF) in the dorsal rumen of 27-28% of the SEF in the Atrium ruminis. Compared to data on digesta retention in the same species, the findings are in line with the overall concept of a high fluid throughput causing a distinct stratification of rumen contents and intraruminal papillation, and necessitating a large omasum for fluid re-absorption. However, the data also show that individual species may not correspond to all the assumptions of the concept, suggesting taxon-specific differences between species. Reasons for these differences cannot be linked to a dietary grass-browse spectrum, but may lie in evolutionary contingency.

A multi-kingdom metabarcoding study on cattle grazing Alpine pastures discloses intra-seasonal shifts in plant selection and faecal microbiota

Diet selection by grazing livestock may affect animal performance as well as the biodiversity of grazed areas. Recent DNA barcoding techniques allow to assess dietary plant composition in faecal samples, which may be additionally integrated by the description of gut microbiota. In this high throughput metabarcoding study, we investigated the diversity of plant, fungal and bacterial taxa in faecal samples of lactating cows of two breeds grazing an Alpine semi-natural grassland during summer. The estimated plant composition of the diet comprised 67 genera and 39 species, which varied remarkably during summer, suggesting a decline of the diet forage value with the advancing of the vegetative season. The fungal community included Neocallimastigomycota gut symbionts, but also Ascomycota and Basidiomycota plant parasite and coprophilous taxa, likely ingested during grazing. The proportion of ingested fungi was remarkably higher than in other studies, and varied during summer, although less than that observed for plants. Some variation related to breed was also detected. The gut bacterial taxa remained stable through the summer but displayed a breed-specific composition. The study provided insights in the reciprocal organisms' interactions affecting, and being affected by, the foraging behaviour: plants showed a high temporal variation, fungi a smaller one, while bacteria had practically none; conversely, the same kingdoms showed the opposite gradient of variation as respect to the animal host breed, as bacteria revealed to be the group mostly characterized by host-specificity.

Contrasting patterns of sexually selected traits in Mediterranean and continental populations of European mouflon

The expression of sexually selected traits in highly dimorphic ungulates may be influenced by environmental quality. Variations in habitat conditions can impose different constraints on the allocation of energy resources to male life-history traits, and possibly alter the female preferences for specific features. Here, we compared the horn growth patterns in male European mouflon Ovis aries musimon living in different habitats (Mediterranean vs. continental) but sharing a common genetic origin. We hypothesized that the expression of sexually selected traits such as horn development should be promoted in more favorable habitat conditions (i.e., Mediterranean). Using linear mixed models on data retrieved from individuals harvested under the same hunting regime, we found longer horns and greater individual variance in horn segment length in the Mediterranean population than in the continental one. Furthermore, Mediterranean rams showed no evidence of compensatory horn growth, as opposed to the continental rams. Unexpectedly, horn base circumference was greater in the continental habitat than in the Mediterranean one. The overall results suggest different patterns of investment in horns in the two populations, with seemingly stronger pressure and consequences of sexual selection on mouflon rams living in more favorable environments. Although the role of hunters' selectivity cannot be excluded a priori, our data suggest that the differences in the expression of sexually selected traits in our study populations may be influenced by environmental conditions. Because sexual selection can impose substantial fitness costs on individuals, further investigations on the trade-offs between reproduction and survival would improve our understanding of the dynamics of mouflon populations living in different environmental conditions.

Response of roe deer (Capreolus capreolus) to seasonal and local changes in dietary energy content and quality

Context In terms of their nutritional physiology, roe deer have been called ‘concentrate selectors’. This implies that they select proteins in their diet and are not able to digest fibre. It is, thus, suggested that in an agricultural landscape, they are unable to digest the high fibre content of arable crops and, thus, suffer and need to be given supplementary feed. Aims Our aim was to determine the nutrient composition and energy content of the roe deer diet in an agricultural habitat compared with that in a natural forest habitat. Methods Rumen contents of 245 roe deer were collected to represent each month of the year for 3 years, weighed, and analysed by standard methods for nutrient and fibre content. Key results Roe deer in the agricultural habitat had rumen contents with significantly higher metabolisable energy (ME) concentrations, with a median of 6.2 MJ ME/kg DM, than did roe deer in the forest habitat, where the median was 5.4 MJ ME/kg DM. The mass of rumen contents in the forest habitat was, on average, 240 g higher than that in the agricultural habitat. Roe deer in the forest habitat compensate for the lower energy concentration in their natural diet by increasing their food intake. The concentration in the agricultural habitat is a result of the higher proportion of easily digestible carbohydrates in the diet. The concentration of crude protein in the rumen contents did not differ statistically between the two areas. In both habitats, the mean crude fibre concentration varied between 24% DM and 34% DM, and was significantly higher in the forest. The concentration of crude fibre selected by the roe deer is similar to the concentration of crude fibre known to be selected by red deer and fallow deer (intermediate feeders) and mouflon (a grazer) (Hofmann 1989). Conclusions The term ‘concentrate selector’ should be replaced by ‘selector’ to avoid misinterpretations. Energy shortfalls were not observed in either of the populations during the study period. Implications Supplemental feeding was not necessary to maintain the population.

Dietary overlap and co-existence of sympatric wild yak, Tibetan wild ass and Tibetan antelope in Arjin Shan National Nature Reserve, Xinjiang Province, China

Context Wild yak (Bos grunniens), Tibetan wild ass (Equus kiang, also known as kiang) and Tibetan antelope (Pantholops hodgsoni, also known as chiru) have been sympatric on the Tibetan Plateau for numerous generations. There is concern over potential dietary competition among them, particularly in winter when their forage resources are scarcer, but little is known about their dietary interactions. Aim We aimed to determine diet composition and dietary overlap of the three ungulate species, and to assess the extent of potential dietary competition among them in order to enhance our understanding of mechanisms underlying their co-existence. We predicted that the three species would widen their choice of forages in winter (December) compared with summer (June–July), and that there would be diet segregation among them, particularly in winter when food resources were scarcer. Methods We collected fresh faecal samples of the three species and reference forage samples from the field during our transect line surveys in the summers of 2012 and 2013, and winter of 2012 in Arjin Shan National Nature Reserve (ANNR) of Xinjiang Province, China. Slides of faecal samples were prepared for microhistological analysis, and plant fragments in faecal samples were identified under microscope. Relative percentage frequency of diet plant species, diet breadth and dietary overlap were calculated. Key results The three species consumed similar forage plants, but varied greatly in their percentage use of the available forages. Wild yak mainly fed on sedges in summer and graminoids in winter, supplemented with forbs. Kiang consumed mainly forbs in summer and browse in winter, and chiru mainly fed on graminoids and forbs in summer. Wild yak had the widest choice of forages, and kiang had the narrowest one in summer, but both wild yak and kiang became less selective in their food choice in winter, resulting in higher diet breadth. The dietary overlaps among them, as represented by Pianka’s index, were generally low, ranging from 0.26 between chiru and kiang to 0.51 between wild yak and kiang. The dietary overlap between wild yak and kiang decreased from summer (0.51) to winter (0.35), suggesting an increased dietary divergence. Key conclusion Our study reveals that the three species are ‘opportunistic feeders’, able to cope with coarse forage resources. There is dietary segregation among them as indicated by low dietary overlap, suggesting risk of potential competition for diets. We suggest that competition may have shaped their dietary divergence, contributing to their co-existence in ANNR. Implication Although there is dietary segregation among the three species in ANNR, it is not possible to make definitive conclusions about interspecific competition from these results. Further studies are needed to investigate if there is spatial and habitat segregation among them, which may facilitate their dietary divergence and thus contribute further to their co-existence in ANNR. Continued efforts are also needed to monitor their population dynamics and status of forage resources in order to prevent overgrazing.

Intra- and interspecific differences in diet quality and composition in a large herbivore community

Species diversity in large herbivore communities is often explained by niche segregation allowed by differences in body mass and digestive morphophysiological features. Based on large number of gut samples in fall and winter, we analysed the temporal dynamics of diet composition, quality and interspecific overlap of 4 coexisting mountain herbivores. We tested whether the relative consumption of grass and browse differed among species of different rumen types (moose-type and intermediate-type), whether diet was of lower quality for the largest species, whether we could identify plant species which determined diet quality, and whether these plants, which could be “key-food-resources” were similar for all herbivores. Our analyses revealed that (1) body mass and rumen types were overall poor predictors of diet composition and quality, although the roe deer, a species with a moose-type rumen was confirmed as an “obligatory non grazer”, while red deer, the largest species, had the most lignified diet; (2) diet overlap among herbivores was well predicted by rumen type (high among species of intermediate types only), when measured over broad plant groups, (3) the relationship between diet composition and quality differed among herbivore species, and the actual plant species used during winter which determined the diet quality, was herbivore species-specific. Even if diets overlapped to a great extent, the species-specific relationships between diet composition and quality suggest that herbivores may select different plant species within similar plant group types, or different plant parts and that this, along with other behavioural mechanisms of ecological niche segregation, may contribute to the coexistence of large herbivores of relatively similar body mass, as observed in mountain ecosystems.

Human disturbances, habitat characteristics and social environment generate sex-specific responses in vigilance of Mediterranean mouflon

In prey species, vigilance is an important part of the decision making process related to predation risk effects. Therefore, understanding the mechanisms shaping vigilance behavior provides relevant insights on factors influencing individual fitness. We investigated the role of extrinsic and intrinsic factors on vigilance behavior in Mediterranean mouflon (Ovis gmelini musimon×Ovis sp.) in a study site spatially and temporally contrasted in human pressures. Both sexes were less vigilant in the wildlife reserve compared to surrounding unprotected areas, except for males during the hunting period. During this period, males tended to be less strictly restricted to the reserve than females what might lead to a pervasive effect of hunting within the protected area, resulting in an increase in male vigilance. It might also be a rutting effect that did not occur in unprotected areas because males vigilance was already maximal in response to human disturbances. In both sexes, yearlings were less vigilant than adults, probably because they traded off vigilance for learning and energy acquisition and/or because they relied on adult experience present in the group. Similarly, non-reproductive females benefited of the vigilance effort provided by reproductive females when belonging to the same group. However, in the absence of reproductive females, non-reproductive females were as vigilant as reproductive females. Increasing group size was only found to reduce vigilance in females (up to 17.5%), not in males. We also showed sex-specific responses to habitat characteristics. Females increased their vigilance when habitat visibility decreased (up to 13.8%) whereas males increased their vigilance when feeding on low quality sites, i.e., when concomitant increase in chewing time can be devoted to vigilance with limited costs. Our global approach was able to disentangle the sex-specific sources of variation in mouflon vigilance and stressed the importance of reserves in managing and conserving wild sheep populations.