Diet of Hoffmann’s two-toed sloth (Choloepus hoffmanni) in Andean forest

The Hoffmann’s two-toed sloth (Choloepus hoffmanni) is a species which could potentially be evaluated as threatened, but data on its natural history in wild conditions are still insufficient. The diet in wildlife of C. hoffmanni was studied through of microhistological analysis of indigestible fragments of leaves found in 43 feces samples collected of the 47 samples found in an Andean forest reserve south of Bogotá, Colombia. Four samples were highly decomposed and were not collected. A reference collection was made of 29 tree species where the feces were found or two-toed sloth were observed, to compare with the plant fragments found in the feces. Seventeen species and six fragments of foliar epidermis of undetermined species were identified in sloth diet. Based on this analysis, C. hoffmanni is a generalist folivore, ingesting a wide variety of plant leaves. Based on frequency of occurrence, relative frequency, and percent cover by volume, Brunellia sibundoya, Cordia cylindrostachya, Citharexylum sp., Quercus humboldtii, and Clethra fagifolia made up most (74%) of the diet of C. hoffmanni in an Andean forest. Comparing the plant species found in the feces with the reference collection, C. hoffmanni appears to deposit feces at the base of the trees that it consumes.

First quantitative data on the feeding ecology of an arid zone rodent, the Common gundi (Ctenodactylus gundi)

One species of the family Ctenodactylidae, the Common gundi, Ctenodactylus gundi, occupies a restricted area between the Saharan and Mediterranean domains where annual rainfall is between 50 and 400 mm. Its presence seems also conditioned by the vegetation, so its feeding ecology was investigated by the microhistological analysis of faeces collected in two stations (Baniane and Bazem) of the Aurès massif (Eastern Algeria) during two years from June 2015 to May 2017, and by the evaluation of the available food. The diet included a total of 34 plant species, 16 in Baniane and 20 in Bazem. Results show that in Baniane, Asteraceae were predominant with Artemisia herba-alba (relative abundance, A% = 33.13%), followed by Fabaceae with Argyrolobium uniflorum (A% = 20.32%) and Poaceae with Aristida sp. (A% = 14.95%). In Bazem, the most consumed plant species were Lamiaceae with Thymus ciliatus (A% = 42.77%) and Poaceae with Lolium rigidum (A% = 13.19%). Overall, C. gundi fed on a large number of plant species, and its diet appeared to be influenced more by the diversity than by the availability of vegetation. Seasonal variations in diet indicate that this rodent eats perennial vegetation throughout the year and opportunistically consumes annual plants to a lesser extent in the spring, with a certain time shifting between the two stations probably due to rainfall and temperature differences.

Spring diet differs among age-sex classes in Atlas Barbary sheep (Ammotragus lervia lervia) in a fenced nature reserve, Morocco

Atlas Barbary sheep, Ammotragus lervia lervia, are the only wild caprinid of Northwest Africa. Some studies have investigated their feeding ecology, but there is no information on intraspecific dietary variation. Therefore, we determined the spring diet and its variation between age-sex classes in Atlas Barbary sheep within a fenced nature reserve in the Western High Atlas mountain range, Morocco. We used faecal microhistological analysis to assess diet composition based on a reference epidermis catalogue. The habitat was a highly diversified open mixed forest with 61 identified species (55 genera; 24 families). The herbaceous layer was dominated by grasses, mainly Stipa capensis. Atlas Barbary sheep revealed to be opportunistic grazers, consuming 44 forage species; grasses and forbs constituted 87% of the overall diet. There were significant intraspecific dietary differences. Rams showed a more diverse (42 species) and distinct diet compared to those of ewes (22 species) and juveniles (lambs + yearlings) (only 10 species). All sex-age classes were mostly grazers, adults feeding on grasses and forbs in similar proportions, whereas juveniles feeding basically on grasses (more than 70% of their diet) and almost no forbs. Ewes and juveniles feed on browse at a higher proportion than rams do. Our findings would be useful for the restoration and management of the habitat and food resources within the reserve.

Molecular dietary analyses of western capercaillies (Tetrao urogallus) reveal a diverse diet

ABSTRACTConservation strategies centred around species habitat protection rely on species’ dietary information. One species at the focal point of conservation efforts is the herbivorous grouse, the western capercaillie (Tetrao urogallus). Traditional microhistological analysis of crop contents or faeces and/or direct observations are time-consuming and at low taxonomic resolution. Thus, limited knowledge on diet is hampering conservation efforts. Here we use non-invasive environmental DNA (eDNA) metabarcoding on DNA extracted from faeces to present the first large-scale molecular dietary analysis of capercaillies. Faecal samples were collected from seven populations located in Norway (Finnmark, Troms, Trøndelag, Innlandet) and France (Vosges, Jura, Pyrenees) (n=172). We detected 122 plant taxa belonging to 46 plant families of which 37.7% of the detected taxa could be identified at species level. The average dietary richness of each sample was 7 ± 5 SD taxa. The most frequently occurring plant groups with the highest relative read abundance (RRA) were trees and dwarf shrubs, in particular, Pinus and Vaccinium myrtillus, respectively. There was a difference in dietary composition (RRA) between samples collected from the different locations (adonis F5,86= 11.01, p <0.05) and seasons (adonis F2,03= 0.64, p <0.05). Dietary composition also differed between sexes at each location (adonis F1,47 = 2.77, p <0.05), although not significant for all data combined. In total, 35 taxa (36.84% of taxa recorded) were new capercaillie food items compared to existing knowledge. The non-invasive molecular dietary analysis applied in this study provides new ecological understanding of capercaillies’ diet which can have real conservation implications. The broad variety of diet items indicates that vegetation does not limit food intake. This plasticity in diet suggests that other factors including disturbed mating grounds and not diet could be the main threat to their survival.

Diet selection and habitat use by the mountain vizcacha (Lagidium viscacia) in the Southern Andean Precordillera (Argentina)

Lagidium viscacia is considered as a fragile species with patchy distribution, a strict habitat specialist and an obligatory diet specialist. The Southern Andean Precordillera constitutes an interesting environment to analyze the species’ presence across the altitudinal gradient. Diet selection and habitat use were studied in the summit plateau, characterized by rigorous conditions and vegetation representative of the Southern Puna. Pellet groups were counted in transects perpendicular to rock formations, and diet and vegetation were seasonally analyzed using microhistological analysis and point-quadrat transects. Vizcachas were strictly associated with rock formations at middle and high altitudes, with higher occurrence on the mountain summit where grasslands surrounded the rock formations. Vizcachas avoided shrubs associated with rock formations and preferred grasses on sandy soils. Phenological changes slightly affected the selective diet that involves a considerable search effort and risky feeding activity. Puna grasslands constituted attractive feeding places where L. viscacia’s activity decreased with distance from rock shelters as expected for a central-place forager. Habitat partitioning allows coexistence with Ctenomys mendocinus, despite the high dietary overlap between these central-place species. The high mobility and broad diet of Lama guanicoe reduce the competition risk. Lepus europaeus preferred shrubs and forbs, determining a discrete dietary overlap with vizcachas.

Comparative dietary analysis of the black-flanked rock-wallaby (Petrogale lateralis lateralis), the euro (Macropus robustus erubescens) and the feral goat (Capra hircus) from Cape Range National Park, Western Australia

The black-flanked rock-wallaby (Petrogale lateralis lateralis) is a threatened species, once widespread throughout Western Australia but now restricted to disjunct populations including those of Cape Range National Park. It is a herbivore with a foraging range restricted to rocky outcrops and, as such, may be impacted by competition for resources from other native or introduced herbivores. This study compared the diet of the black-flanked rock-wallaby with those of co-occurring species, the euro (Macropus robustus erubescens) and the feral goat (Capra hircus), from two gorges at Cape Range National Park, to determine whether there is overlap in dietary niches. Diet composition was determined using microhistological analysis of faecal pellets in comparison with reference plant material. The black-flanked rock-wallaby diet consisted predominately of browse/forbs with some variation across seasons (63% in summer months; 74% in winter months); this overlapped significantly with the diet of goats (Schoener Index: 0.79–0.88), but not euros (SI: 0.41–0.57), whose diet consisted predominantly of grasses (72–78%). There was, however, a significant overlap in the consumption of plants with stellate hairs for all three herbivores (SI: 0.89–0.98). Dietary overlap between rock-wallabies and goats may indicate a mechanism for competition, supporting continuing measures for reduction of goat numbers in Cape Range National Park.

Dietary resource use and competition between white-tailed deer and introduced sika deer

Content Native communities of herbivores have evolved fundamental dietary niches that avoid or minimise competition; the introduction of exotic species can change dietary niches, cause overlap in resource use, and result in competition for resources. Aims We compared niche breadth, overlap in diet, and quality of diet between introduced sika deer and native white-tailed deer in Maryland, USA. We investigated these changes in free-ranging populations where both species are allopatric as well as when they are sympatric. Methods We used microhistological analysis of faecal samples to determine the percentage of resources used by sika deer and white-tailed deer, as measured between geographical areas of similar habitat quality. We compared resource use specifically by controlling for harvest pressure and resource availability, which are known to alter resource use other than the presence of an additional deer species. Key results We observed a significant resource overlap (range 63–88%) between species. In the presence of sika deer, white-tailed deer displayed an increased niche breadth (108%) and a lower diet quality (17%). Sika deer consumed the same resources that comprised 78% of white-tailed deer diet. Unlike other native ungulates that have dietary overlap with white-tailed deer, sika deer is neither temporally nor geographically segregated in habitat use. Conclusions Resource overlap and changes in niche breadth and diet quality during sympatry strongly denote dietary competition between sika deer and white-tailed deer. This competition results in white-tailed deer altering the dietary selection, thereby consuming lower-quality forage. Implications White-tailed deer are concentrate selectors and require higher diet quality than do sika deer, which can tolerate diets higher in fibre, consistent with their classification as intermediate feeders. A decrease in the nutritional quality of resources used by white-tailed deer could contribute to the decline of white-tailed deer over time and allow the continued spread of sika deer.