Diet selection of the southern vizcacha (<Emphasis Type="Italic">Lagidium viscacia</Emphasis>): a rock specialist in north western Patagonian steppe,Argentina

The southern vizcacha (Lagidium viscacia) is a rock specialist that inhabits small colonies in isolated rocky outcrops of northwestern Patagonia. This study analyzes its diet selection in relation to food availability, establishes the degree of dietary specialization, and discusses the potential competition with exotic herbivores. Diet composition and food availability were determined in summer and winter in eight rocky outcrops by microhistological analysis of fecal pellets, and food availability was estimated by the Braun Blanquet cover abundance scale. Vegetation cover differences were detected by using a random analysis of variance (ANOVA) factorial block design, and dietary preferences were determined by the confidence interval of Bonferroni. The southern vizcacha showed a specialized feeding behavior despite the consumption of a wide variety of items. Their diet was concentrated on a few types of food, mainly grasses, and the trophic niche was narrow and without seasonal variations. In winter, when food was scarce and of lower quality than summer, diet was dominated by Stipa speciosa, suggesting a selection according to the selective quality hypothesis. Our results (narrow trophic niche, restricted activity near rocky outcrops, and a diet with high proportions of low-quality grasses) showed that the vizcacha is an obligatory dietary specialist, and these characteristics made it highly vulnerable to changes in food availability. In this scenario, overgrazing caused by alien species with similar diets, as the European hare and livestock, could negatively affect their colonies.     

Graminivory and Fallback Foods: Annual Diet Profile of Geladas (<Emphasis Type="Italic">Theropithecus gelada</Emphasis>) Living in the Simien Mountains National Park,Ethiopia

All primates show some dietary flexibility, particularly during food shortages. Foods consumed during times of scarcity (i.e., fallback foods) strongly influence the ecology and evolution of a species. Geladas (Theropithecus gelada) eat primarily graminoid leaves (i.e., grasses and sedges), but also consume other diet items (e.g., underground storage organs), especially in the dry season. We investigated the feeding ecology of wild geladas in the Sankaber region of the Simien Mountains National Park, Ethiopia across 12 mo. We asked how the gelada diet in this region, which is disturbed by livestock and agriculture, correlated with food availability and whether underground foods are fallback foods. We quantified the monthly diets of adults from eight reproductive units using instantaneous scan sampling, and seasonal aboveground and underground food availability using point-intercept transects and soil core sampling. Geladas primarily consumed graminoid leaves year-round (76.3% of the annual diet, 36.2–93.2% of the monthly diet) but spent considerable time consuming underground foods in the dry season (14.0% of the annual diet, 11.1–49.7% of the diet across dry season months). Graminoid consumption increased with graminoid availability, and underground food consumption decreased with graminoid availability. Underground food availability did not vary significantly between the dry and wet season sampling months, supporting the hypothesis that underground foods are fallback foods for geladas. We then compiled data from gelada feeding studies and found that underground foods are an important dry season diet item across study sites, but geladas rely more heavily on underground foods in habitats more heavily influenced by humans. Understanding the range and effects of primate dietary flexibility in human-modified habitats will contribute to a better understanding of how changing environments shape primate ecology and evolution.     

Diet selection by European hares (Lepus europaeus) in the alpine zone of the Snowy Mountains, Australia

European hares (Lepus europaeus) are grazers and open grassland specialists that are replaced in mountain areas of their natural range in the northern hemisphere by browsing/intermediate feeding mountain hares (Lepus timidus), but in their introduced range in the southern hemisphere, occupy the alpine zone. We used micro-histological identification of plant fragments and germination of seeds in faecal pellets of L. europaeus from the Snowy Mountains, Australia, to determine diet. We asked whether diet shifted and/or diet breadth expanded in response to seasonally reduced food availability, particularly during winter. If so, did the constraints of food availability in the alpine zone lead to the diet mirroring that of L. timidus in its native alpine habitat. The diet of L. europaeus was dominated by grasses, herbs and shrubs. The main diet items in summer were grasses (70 %) and herbs (28 %). Grasses declined in the diet between summer and autumn when herbs increased to co-dominance, with a further change after establishment of the winter snowpack to a greater preponderance of shrubs (43 % compared with a maximum of 3 % in snow-free months). L. europaeus selected a wider range of plants in winter (59 species compared with 39 in summer) and diet was significantly more variable in winter than in autumn or summer (and in autumn than summer). We concluded that the persistence of L. europaeus in alpine areas of the southern hemisphere is testament to their ability to expand their dietary breadth to occupy mountain climatic zones normally occupied by L. timidus.     

Diet of the brown hare (Lepus europaeus) and food availability in northern Patagonia (Mendoza, Argentina)

The brown hare, a Leporid widespread in the world, is now dispersed across Argentina after its introduction at the end of the 19th century. Studies on hare feeding ecology are important to evaluate a potential competition with domestic and native wild herbivores. This study analyses the brown hare diet in relation to food availability, and dietary overlaps with several herbivores in northern Patagonia. Food availability was estimated by point-quadrat transects, and hare diet by microhistological analysis of faeces, carried out in five habitats in five seasonal samplings. Significant differences were detected by Kruskall–Wallis ANOVA with multiple comparisons by Tukey test. Feeding selection was detected by χ² test, and dietary preferences by the confidence interval of Bailey. Grasses and chamaephytes were the most available plant categories, with Stipa, Panicum and Acantholippia as main species. Grasses and phanerophytes were the main dietary categories, including Poa, Panicum, Bromus, Adesmia and Prosopidastrum. The phanerophytes Prosopidastrum and Ephedra were more eaten in winter, when the main food item (Poa) presented lower availability. A higher dietary proportion of the chamaephyte Acantholippia occurred in rocky habitats, where the coarse dominant grasses were always avoided. Hares shared most food items with several wild and domestic herbivores in northern Patagonia. The lack of preference for forbs differentiates brown hares from other herbivores. However, hares exhibited important dietary similarities with plain and mountain vizcachas, goats and horses, and an interspecific competition for food is highly probable.     

Trophic interactions between two medium-sized mammals: the case of the native Dolichotis patagonum and the exotic Lepus europaeus in a hyper-arid ecosystem

As medium-sized herbivores, the exotic Lepus europaeus (European hare) and the native Dolichotis patagonum (mara) have been considered ecological equivalents. These species coexist in Ischigualasto Provincial Park, a hyper-arid ecosystem with scarce food resources. Our objective was to evaluate diet composition, relationship between diets and food availability, and trophic relationships between both herbivores. Collection of feces and vegetation sampling were made in the Mesquite woodland community. Diet composition was analyzed by microhistological analysis of feces. In both seasons, shrub species represented the most abundant cover type in the area, and annual forbs and grasses appeared in the wet season. Herbivores showed similar dietary ecology: shrubs were the main food items along the year, showing a higher plasticity compared to their diets in other ecosystems, where they selected mostly grasses. The mara selected shrubs such as Atriplex sp. and Prosopis torquata, whereas the European hare selected Cyclolepis genistoides, Atriplex sp., and Bulnesia retama. During the wet season, both herbivores supplemented their diets with grasses and annual forbs. In the dry season, there was increased consumption of cacti, such as Tephrocactus sp. The mara and the European hare are likely close ecological equivalents, in terms of dietary similarity, and they showed strong dietary overlap across the dry season (over 60 %). Thus, we can assume the existence of a potential trophic competition between mara and European hare, especially during the season when food resources are scarce. These results can be important for the management of drylands in South America, where populations of threatened herbivorous species, such as the mara, coexist with exotic animals, sharing spatial and trophic resources even in protected areas.     

Summer feeding strategy of Spanish ibexCapra pyrenaica and domestic sheepOvis aries in south-eastern Spain

The feeding strategies of the Spanish ibexCapra pyrenaica Schinz, 1838 and sheepOvis aries Linnaeus, 1758 during summer in the alpine area of Sierra Nevada in south-eastern Spain were compared. The degree of vegetation use by the two ungulates, food availability, diet composition, species selection indices and the effect of plant availability and chemical composition on diet selection were analysed. The available biomass of herbaceous and woody resources was 87 and 13%, respectively. The degree of use was 15% for herbaceous vegetation and 10.3% for woody vegetation. The most used species were those with moderate amounts in diet composition of both ruminants. The main plant groups consumed by Spanish ibex were graminoids (57.5%), shrubs (20.5%) and chamaephytes (14.3%). Sheep consumed graminoids (41.6%), forbs (32.3%) and chamaephytes (20.9%). There was a significant correlation between the two diets, with an overlap of 56.3%. The highest indices of selection were found in items with moderate-low availability and which comprised moderate levels in the diet composition of the two species. Spanish ibex mainly selected diet according to availability, while sheep selection depended on protein content. The ibex consumed cell wall-rich resources such as grasses and shrubs, while the sheep consumed higher quality feed and includes more forbs in its diet.     

Dietary classification of extant kangaroos and their relatives (Marsupialia: Macropodoidea)

Kangaroos and kin (superfamily Macropodoidea) are the principal endemic herbivores of Australia and the most diverse radiation of marsupial herbivores ever to have evolved. As is typical of other herbivore groups (e.g. bovids), dietary niches span fruit, fungi, dicot leaves and monocot grasses in both specialists and generalists, but to date dietary classification has been largely ad hoc and poorly tied to actual dietary ecological data. Here we provide a simple dietary classification of the Macropodoidea based on an extensive literature survey. Intake of four major dietary items – grasses, dicot leaves, fruits and seeds, and fungi – was assessed using proportional intake for 19 species and categorical (ranked intake) data for 37 species. Statistical comparisons with cluster and principal components analyses aligned species into four dietary groups. Members of the first group have diets that primarily consist of fungi and fruits. Relative proportions of grasses to dicot leaves separate the remaining species into browser (more than 70% dicots), grazer (more than 70% grasses) and mixed feeder groups. Comparison of our diet‐based classification with a prevailing scheme based on dental morphology suggests that most species with what has traditionally been viewed as a ‘browser‐grade dentition’ are actually mixed feeders. This suggests that either morphology and diet are not tightly linked or that morphological differences between the dentitions of browsers and mixed feeders are subtle and have been overlooked. A positive correlation was found between body mass and average proportional intake of grass in the diet of macropodoids. This parallels the situation found in bovids, as well as the percentage cut‐off between dietary groups. These trends suggest that some underlying ecophysiological constraints may influence food choice in mammalian herbivores providing useful pointers to the diets of extinct taxa.     

植食性小哺乳类营养生态学的研究：高原鼠兔的食物选择模式与食物质量

本文报道了高原鼠兔(Ochotona curzoniae)的食物模式,食物选择指数及食物项目的营养成分,并探讨食物质量与食物选择的关系。高原鼠兔主要选食双子叶植物叶片。食物组成与饲料可利用量的比较分析,揭示出高原鼠兔对各种食物项目的选择程度。在排除其它营养因子的作用后,复回归分析的结果表明,食物百分率与磷含量之间具有显著的正相关。各种食物项目不同营养成分与食物百分率之间相关关系不一致。从而进一步验证了食物选择决定于饲料可利用量和食物质量的假设。     

Black-backed jackal diet at Mokolodi Nature Reserve, Botswana

We examined the feeding habits of black‐backed jackals at Mokolodi Nature Reserve, Botswana, by analysing 237 scats collected between November 1995 and February 1997. Jackal dietary habits reflected the availability of a wide variety of food items and the differential vulnerability of prey. Potential animal and plant food available to jackals varies throughout the year because of its seasonal character. Seasonality of prey occurrence in scats was pronounced for small mammals, miscellaneous fruits and invertebrates. Across all seasons, mammals were the most common food resource (32.4%, n = 168), followed by anthropogenic items (14.8%), fruits (12.9%), invertebrates (10.8%), birds (8.5%), unidentified items (3.5%) and reptiles (1.4%). The presence of domestic mammals and poultry remains in scats reveals their importance in the diet of jackals and the tendency of jackals to frequent human settlements in search of food. Some ecological implications of jackal dietary habits are also explored.     

Diet of the mara (Dolichotis patagonum), food availability and effects of an extended drought in Northern Patagonia (Mendoza,Argentina)

The mara is a near threatened Caviomorph, endemic to Argentina. Studies on feeding ecology allow assessment of the dietary adaptability of maras to habitat changes. The mara diet and food availability on two sampling sites, belonging to distinct landscapes of Northern Patagonia, were estimated using microhistological analysis and point-quadrat transects, over four seasons, and besides during an extended drought. Significant differences were detected by Kruskall-Wallis ANOVA, feeding selection by the χ² test, and dietary preferences by Bailey's confidence interval. Grasses dominated food availability, with Panicum and Poa as major species, followed by shrubs and scarce forbs. Plant cover and forbs increased in spring and summer. The drought caused a strong decrease in plant cover and proportion of grasses. Maras ate all grass species, most forbs and several shrubs. Grasses dominated the diet, with Poa and Panicum being the major species, supplemented by the shrubs Lycium and Prosopis. Maras ate more grasses and forbs in spring and summer, and shrubs in autumn and winter. More shrubs and forbs, and less grasses, were eaten during the drought. Plant categories were used selectively only in autumn and winter, and in the drought period, with preference for shrubs and avoidance of grasses. Bromus, Poa, Plantago and Prosopis were preferred, and Panicum avoided. The mara qualified as a grazer but shifted to a mixed feeder during the drought. Dolichotis patagonum shared habitats with several big and medium-sized herbivores and showed the highest dietary similarities with plain vizcachas, brown hares and horses. Protective measures for natural habitats are needed, given that increasing impacts on food resources and habitat quality could be threats to the survival of maras and other wild vertebrates in Northern Patagonia.     

Problems with measuring diet selection of terrestrial,mammalian herbivores

Abstract The validity of methods used to measure diet selection has often been overlooked. This paper examines problems associated with the scale of food availability, perception of food by animals, measures of dietary composition, measures of food availability and diet selection indices. Most problems can be reduced by the choice of techniques consistent with the objective and degree of accuracy required, both of which should be clearly stated. In particular, the measured sample of food utilized by the animal should be spatially and temporally matched to the scale of food availability under consideration. In the past, researchers have tended to overstate the accuracy of their results. We support the view that the most appropriate analysis of diet selection is ranking food items in order of selection according to the value of the selection index.     

The dietary overlap between red kangaroos (Macropus rufus) and sheep (Ovis aries) in the arid rangelands of Australia

Abstract The interaction between red kangaroos and sheep in the more arid areas of Australia was examined by means of a large-scale manipulative experiment. The diets of red kangaroos and sheep grazing together and separately in large paddocks were studied to assess whether competition for food might influence diet selection in these species. Diets and the amount of intra- and interspecific dietary overlap varied in accordance with pasture conditions. At pasture biomasses ranging from 50 to 200 g m^?2 (dry weight [wt]), the diets of red kangaroos and sheep overlapped by 58–73%, with forbs and grasses being the major items in the diets of both species. The diets of both sheep and red kangaroos under different experimental regimes were similar. In dry times (pasture biomass 40–50 g m^?2 (dry wt) more shrubs were eaten by both species and the amount of dietary overlap tended to be lower (52–66%). The diets of kangaroos were similar between paddocks. However, in paddocks containing both species sheep consumed proportionately more chenopodaceous shrubs and fewer grasses than those in ‘kangaroo-free’ paddocks.     

Dietary generalists and nutritional specialists: Feeding strategies of adult female blue monkeys (Cercopithecus mitis) in the Kakamega Forest,Kenya

Generalist primates eat many food types and shift their diet with changes in food availability. Variation in foods eaten may not, however, match variation in nutrient intake. We examined dietary variation in a generalist‐feeder, the blue monkey (Cercopithecus mitis), to see how dietary food intake related to variation in available food and nutrient intake. We used 371 all‐day focal follows from 24 adult females (three groups) in a wild rainforest population to quantify daily diet over 9 months. We measured food availability using vegetation surveys and phenology monitoring. We analyzed >700 food and fecal samples for macronutrient content. Subjects included 445 food items (species‐specific plant parts and insect morphotypes) in their diet. Variation in fruit consumption (percentage of diet and total kcal) tracked variation in availability, suggesting fruit was a preferred food type. Fruits also constituted the majority of the diet (by calories) and some fruit species were eaten more than expected based on relative availability. In contrast, few species of young leaves were eaten more than expected. Also, subjects ate fewer young leaves (based on calories consumed) when fruit or young leaves were more available, suggesting that young leaves served as fallback foods. Despite the broad range of foods in the diet, group differences in fiber digestibility, and variation that reflected food availability, subjects and groups converged on similar nutrient intakes (grand mean ± SD: 637.1 ± 104.7 kcal overall energy intake, 293.3 ± 46.9 kcal nonstructural carbohydrate, 147.8 ± 72.4 kcal lipid, 107.8 ± 12.9 kcal available protein, and 88.1 ± 17.5 kcal structural carbohydrate; N = 24 subjects). Thus, blue monkeys appear to be food composition generalists and nutrient intake specialists, using flexible feeding strategies to regulate nutrient intake. Findings highlight the importance of simultaneously examining dietary composition at both levels of foods and nutrients to understand primate feeding ecology.     

Dry Season Diet of the Sloth Bear (Melursus ursinus) in Hadagarh Wildlife Sanctuary,Eastern India

Dry season food habit of sloth bear (Melursus ursinus) in Hadagarh Wildlife Sanctuary was characterized by scat analysis. Importance value index (IVI) of contribution of different food items in the diet of sloth bear was estimated from the undigested food remnants. Percentage of dry weight and IVI score of Ziziphus fruits was highest, termites were the most frequently occurring food item in the diet and percentage of frequency occurrence was equal for both fruits and insects. The present study, as compared to previous studies, suggests that the dietary preference of sloth bear varies according to availability of food and the habitat quality.     

Dietary breadth and resource use of François' langur in a seasonal and disturbed habitat

Previous studies of Trachypithecus species indicated that they were selective feeders that concentrated on relatively few food species/items. From January to December 2005, I quantified potential food availability and the food species/items eaten by five groups of François' langur (Trachypithecus francoisi) in the Mayanghe Nature Reserve (MNR), People's Republic of China. These langurs fed on 164 species, of which the top ten accounted for 51% of all feeding records. Langurs consumed more species (91) in the spring than in other seasons (73 summer, 75 autumn, and 67 winter), and only 38 species were consumed in all seasons. Nontree food species, such as bushes and lianas, accounted for 47% of the total feeding records and for a majority (68%) of the feeding records in winter. The annual diet consisted of leaves (64% of feeding records), fruit and seed (32%), and other nonfoliage items (4%); the langurs switched from being more folivorous in spring (93%) and summer (79%) to being more frugivorous in autumn (53%) and winter (56%). There was no correlation between the proportion of feeding records and the food availability in the most frequently consumed species, indicating that these langurs were selective feeders; there were significant correlations between consumption and abundance in both the entire set of 112 food species and the set of 86 infrequently consumed species, indicating that foods that are more available are eaten more frequently. It appeared that in the seasonal and disturbed habitat, feeding decisions and diet composition of the langur may be driven more by food availability, and less by animal's selectivity, than at other sites. The results indicate that François' langur copes with habitat alterations by broaden its dietary breadth; this has implications for the adaptive significance of dietary breadth, and has implications for future conservation strategies for species which exist in degraded habitats. Am. J. Primatol. 73:1176–1187, 2011. © 2011 Wiley Periodicals, Inc.     

Food of three upland game birds in Selengei Area, Kajiado District, Kenya

Foods taken by yellow-necked spurfowl, crested francolin and helmeted guinea-fowl were investigated over a 22-month period. Bulblets of sedge (Cyperus sp.) were the major plant item in the diet of all three species. Other foods were seeds and fruits of forbs, florets and fruits of grasses, leaves of forbs and grasses and insects. Insect use increased following the rains, as did the use of florets of the grasses. Except for Cyperus sp. there was little overlap of food items taken by the crested francolin and the guinea-fowl, but both were in competition with the yellow-necked spurfowl for some species of plants. This was probably due to size of food items, that is, there was a direct relationship between size of bird and size of foods taken. Forag ing habits also influence food intake.     

Estimation of food composition of Hodotermes mossambicus (Isoptera: Hodotermitidae) based on observations and stable carbon isotope ratios

Abstract The diet of the harvester termite Hodotermes mossambicus was investigated at two sites with distinct dietary components: C₄ grasses (δ¹³C isotope values, ?13.8‰ to ?14.0‰) and C₃ plants (δ¹³C isotope values, ?25.6‰ to ?27.1‰). By comparing observations of food items carried into the colony by the termites and carbon isotope ratios of whole termites (that determined assimilated carbon), the relative proportion of the C₃ and C₄ plant food components of the termite diet was estimated. There was agreement between the observational data and stable carbon isotopic data, with grass representing approximately 93% of the diet of H. mossambicus at two study sites (urban and rural) on the South African highveld. However, when correcting for mass of food items, that is, C₃ and C₄, carried by termites, the proportion of grass (C₄) in the diet may be underestimated.     

Dietary Variability of Mountain Gorillas in Bwindi Impenetrable National Park,Uganda

Data on intraspecific dietary variability has important implications for understanding flexibility in foraging behavior, habitat utilization, population dynamics, and social behavior and may also assist in conservation efforts. We compared food availability and diet of a group of mountain gorillas (Gorilla beringei beringei) at a high altitude site and 2 groups at a low altitude site in Bwindi Impenetrable National Park, Uganda, from September 2001 to August 2002. Plant species diversity was greater at the low altitude site than at the high altitude site. The two groups at the low elevation consumed more plant species (140 species vs. 62 species), and a greater number of fruit species per mo (7 vs. 3 species) and per yr (36 vs. 11 species) than the high altitude group did. Furthermore, each group shared <51% of important fibrous food items in their diet with the 2 other groups. There is no significant difference in the proportion of days fruit remains were found in the dung among groups. Finally, according to Ivlev's electivity index, all groups positively selected the majority of food items in their diets. We attribute a large proportion of dietary variation between locations to differences in fruit availability and plant species composition between sites. Differences between groups at the low altitude site may be due to variation in food profitability—more profitable foods available to choose in the same area—within their overlapping home range, or group traditions. A comparison of our results with the diets of gorillas of the Virunga Volcanoes in Rwanda and Kahuzi-Biega, DRC shows that eastern gorilla populations have highly variable dietary patterns with limited overlap in species consumed among groups and populations.     

Feeding ecology and diet of the southern geladas (Theropithecus gelada obscurus) in human‐modified landscape,Wollo, Ethiopia

Studying the dietary flexibility of primates that live in human‐modified environments is crucial for understanding their ecological adaptations as well as developing management and conservation plans. Southern gelada (Theropithecus gelada obscurus) is an endemic little‐known subspecies of gelada that inhabits human‐modified landscapes in the northern central highlands of Ethiopia. During an 18‐month period, we conducted this intensive study in an unprotected area of a human‐modified landscape at Kosheme in Wollo to investigate the feeding ecology of southern geladas and their dietary responses to seasonal variations. We quantified the monthly and seasonal diet data from a band of southern geladas using instantaneous scan sampling method at 15‐min intervals, and green grass phenology and availability using visual inspection from the randomly selected permanent plots. The overall average diet of southern geladas at Kosheme constituted grass blades 55.4%, grass undergrounds 13.2%, grass bulbs 5.6%, grass seeds 5.4%, herb leaves 4.0, fruits 7.3%, and cereal crops 5.6%. Grass blade consumption increased with increasing green grass availability, while underground food consumption increased with decreasing green grass availability, and vice versa. Southern geladas spent significantly more time feeding on the grass blades and herb leaves and significantly less time on bulbs during the wet season than the dry season. Underground grass items (rhizomes and corms) were not consumed during the wet season, but made up 22.3% of the dry season diet. Thus, although grass blades are staple diet items for geladas, underground diet items are important “fallback foods” at Kosheme. Our result shows insights into the dietary flexibility southern geladas adopt to cope with human‐modified landscapes of the north‐central Ethiopian Highlands. Thus, the study contributes to a better understanding of how changing environments shape primate ecology and evolution.     

The diet of the capped langur (Presbytis pileata) in a moist deciduous forest in Bangladesh

Capped langurs (Presbytis pileata) in Madhupur National Park in north-central Bangladesh have an annual diet that is comprised largely of mature leaves (42% of 20,460 total feeding records). Among colobine monkeys, only some populations of red colobus (Procolobus badius) have a diet richer in mature leaves. New leaves (11%) and fruit (24%) are the other annually important dietary items. Seasonal breakdown of this diet, however, revealed that during the monsoon months of May through September theP. pileata diet is approximately 50% fruit, including pulpy ripe fruit. This is also the period of maximum fruit availability. Data on diet and food availability indicate that while capped langurs subsist on mature leaves during the dry season (80% of diet from November to March), they select fruit and new leaves and switch to these foods whenever they are available. These data support the hypothesis that the colobine feeding strategy is adapted to cope with seasonal food scarcity.