Food habits of giraffe in Tsavo National Park, Kenya

In the context of a broader ecological investigation, food habits of giraffe were studied in Tsavo National Park (East). The only method employed was direct observation of feeding animals in the field. Each instance in which one animal fed on one individual plant was counted as one food record for this plant species; 4025 records are analysed. A total of sixty-six plant species was found to be eaten, the great majority being trees and shrubs, with a few creepers and vines. There were marked seasonal differences in the diet of giraffe, deciduous trees, shrubs and vines being dominant in the green season, evergreen plants (partly in riverine forest) in the dry season. All the trees and larger shrubs common in the study area were eaten by giraffe, while few records for very small shrubs and none for herbs and grasses were obtained. An analysis of the available vegetation was made in part of the dry-season habitat, and for twenty species the frequency in the habitat was compared with the frequency in the giraffe's diet, revealing selection for or against certain species. Giraffe utilized the upper vegetation layers, where available, but overall c. 50% of all browsing was below 2 m above ground, i.e. within reach of smaller browsers. Results of this study are compared with what is known on food habits of giraffe in other areas. Possible competition of giraffe with other browsers and the relationship between giraffe and their habitat are discussed. Continued survival of giraffe, and other browsers, in Tsavo National Park depends primarily on (1) adequate control of fire, and (2) the impact of future vegetation changes on the amount and variety of available browse plants.     

Working with mahouts to explore the diet of work elephants in Myanmar (Burma)

At an elephant camp in central Myanmar (Burma), we interviewed mahouts and veterinarians to describe the diet of Asian elephants (Elephas maximus) in a mixed-deciduous forest. Elephants showed a broad dietary breadth (103 plant species from 42 families); consumed mostly browse (94% of plant species); and were very selective about plant parts [e.g., many trees were eaten exclusively for their bark (22%) or fruits (14%)]. The fruits from 29 plant species were recorded to be eaten by elephants. Several of these were found as fruit remains, seeds, or seedlings in elephant dung, suggesting a role of Asian elephants in seed dispersal. Work elephants and their mahouts prove to be a rich source of information to understand wild elephant ecology.     

ELEPHANT ECOLOGY IN THE QUEEN ELIZABETH NATIONAL PARK, UGANDA

1. Aerial and ground counts in the Queen Elizabeth National Park from 1963 to 1969 indicate that the number of elephants has more than doubled. The increase appears to be the result of immigration rather than reproduction. 2. Elephant food habits were studied for 10 months in two areas of the Park. In the short-grass/thicket area, browse intake rose markedly whenever the rainfall fell below 50 mm/month. In the tall-grass area without thicket, herbs were eaten frequently during the rains and Cymbopogon grass bases in the dry season. 3. Food availability had an important influence on the diet of elephants. Sometimes, however, elephant were very selective, e.g. for Panicum maximum, Azima tetracantha, Securinega virosa, and Tribulus terrestris. Certain grass inflorescences were selected during the rains, and bases in the dry season. 4. Most browse was consumed in the thicket area during the dry season and most grass was eaten in the tall-grass area of the Park. 5. Stomach and faecal samples gave a similar result and indicated that the diet in the tall-grass area was comparable to that of elephant in Murchison Falls National Park. 6. Analyses of important plant species showed that, in general, tall-grass had a lower crude protein content than short-grass, herbs and browse. Browse leaves had a relatively high crude-protein content in the dry season. Differences were less marked in the rains. 7. Ether extract, or fat content, was high in browse leaves and in Cymbopogon, in particular its bases. These may have been selected in the dry season for this reason. 8. Grass and browse stems were very fibrous and this may have contributed to their being avoided. 9. High carbohydrate levels probably enhanced the palatability of grass bases and browse leaves. 10. Grasses were very siliceous, in particular their bases when contaminated with soil. Elephant took considerable trouble to remove soil. Browse leaves had little silica but were rich in other minerals, and this may have contributed to their greater palatability. 11. Studies of woodland dynamics show a decline in large trees which corresponds to the increase in elephants. In some cases trees have been almost eliminated. Damage to trees indicates that a most important factor in their decline is the elephant. There is some evidence that the trees are eliminated selectively. 12. In the tall-grass area there has been an increase of 46.3% in elephant numbers, but a decline of 80.3 % in buffalo, over the past 15 years. An overall decline in combined biomass of 36.9 % is calculated. Estimates of energy utilization of the annual vegetation production by elephant and buffalo indicates a decline from 6.1 % to 3.9% over this period.     

Ecological separation among browsing ungulates in Tsavo East National Park,Kenya

Summary Data on food habits and habitat preferences of four browsing herbivores (black rhinoceros, giraffe, gerenuk and lesser kudu) were analyzed to assess niche width for each species and niche overlap between pairs of species. All four species depended heavily on woody plants as food, and overlap in the utilization of different plant types (trees and shrubs, herbs, grasses, etc.) was very great in three of six species paris. When individual plant species were considered, markedly less overlap was apparent. Three of the four ungulate species preferred the most densely wooded vegetation type. Overlap in habitat preferences tended to be least in those pairs of species with the greates dietary overlap, which resulted in some degree of ecological separation. This was further increased by differences in browsing level. Seasonal variations in the browsing level of the giraffe had the effect of reducing overlap with the other species in the dry season, when food was in relatively short supply. Whether or not actual competition existed among the four ungulate species could not be established; in any event, it would probably be less important than possible competition exerted by the elephant, the dominant herbivore by far in the ecosystem. The ecological separation evident among the four browsing species probably permitted them to coexist in the area before the elephant reached its present dominant position and started altering the original vegetation.Formerly Tsavo East Research Station, Voi, Kenya     

Seasonal diet preferences of black rhinoceros in three arid South African National Parks

Black rhinoceros diet and browse availability was investigated in Augrabies Falls (AFNP), Karoo (KRNP) and Vaalbos National Parks (VNP) in South Africa. Rhino tracks were followed and 18,804 standard bite volumes recorded. Browse availability of each plant species was recorded by measuring 14,800 plants and calculating reachable browse volume. The diet comprised 51, 53 and 41 plant species in AFNP, KRNP and VNP, respectively, but three species accounted for more than 65% of the diet in each park, making diet less diverse than available browse in AFNP and KRNP. Browse availability explained 14%, 15% and 52% of diet selection in AFNP, KRNP and VNP, with consumption of most plant species significantly different from availability. A few plant species were so highly preferred that browsing intensities were unsustainable, while some common species were totally rejected. Pressure on the eaten browse averaged 4.4%, 14.5% and 1.3% annually of the volume in AFNP, KRNP and VNP. In the dry season, there was a two to sevenfold increase in browsing pressure on species with actively photosynthesizing tissues. A few key species, including Monechma and Zygophyllum species, were identified as potential early warning indicators of black rhino browsing impact.     

Sex and size related differences in the dry season feeding patterns of elephants in Chobe National Park, Botswana

Differences in feeding patterns of the African elephant were examined by sex and age during the dry season in a dystrophic savanna-woodland ecosystem in northern Botswana. Adult males had the least diverse diet in terms of woody plant species, but they consumed more plant parts than family units. The diameter of stems of food plants broken or bitten off was also greater for adult males than for females and subadult males. Adult males spent more time foraging on each woody plant than did females. The number of woody plant species and individuals present were higher at feeding sites of family units than at feeding sites of adult males, indicating that family units positioned themselves at feeding sites with higher species diversity than those of males. We argue that the most likely explanation for these differences is related to the pronounced sexual size dimorphism exhibited by elephants, resulting in sex differences in browsing patterns due to the allometric relationships that govern the tolerance of herbivores for variation in diet quality. From our results this Body Size Hypothesis is accepted rather than the alternative Scramble Competition Hypothesis, which predicts that adult male elephants consume lower quality browse because they are displaced from preferred browse as an outcome of scramble competition with adult females and their offspring. If the feeding patterns of adult male elephants were affected by intersexual scramble competition, we would expect adult males to browse at a higher level in the canopy than the smaller-bodied females and their offspring. No evidence was found for this, although adult females were found to browse at a higher level in the canopy when feeding in close proximity to subadults and juveniles than when feeding alone. Sex differences in elephant browsing patterns are, we propose, of relevance to understanding and managing elephant impacts on African woodlands.     

Seasonal diet changes in elephant and impala in mopane woodland

Elephant and impala as intermediate feeders, having a mixed diet of grass and browse, respond to seasonal fluctuations of forage quality by changing their diet composition. We tested the hypotheses that (1) the decrease in forage quality is accompanied by a change in diet from more monocots in the wet season to more dicots in the dry season and that that change is more pronounced and faster in impala than in elephant; (2) mopane (Colophospermum mopane), the most abundant dicot species, is the most important species in the elephant diet in mopane woodland, whereas impala feed relatively less on mopane due to the high condensed tannin concentration; and (3) impala on nutrient-rich soils have a diet consisting of more grass and change later to diet of more browse than impala on nutrient-poor soils. The phosphorus content and in vitro digestibility of monocots decreased and the NDF content increased significantly towards the end of the wet season, whereas in dicots no significant trend could be detected. We argue that this decreasing monocot quality caused elephant and impala to consume more dicots in the dry season. Elephant changed their diet gradually over a 16-week period from 70% to 25% monocots, whereas impala changed diets rapidly (2?C4?weeks) from 95% to 70% monocots. For both elephants and impala, there was a positive correlation between percentage of monocots and dicots in the diet and the in vitro digestibility of these forage items. Mopane was the most important dicot species in the elephant diet and its contribution to the diet increased significantly in the dry season, whereas impala selected other dicot species. On nutrient-rich gabbroic soils, impala ate significantly more monocots than impala from nutrient-poor granitic soils, which was related to the higher in vitro digestibility of the monocots on gabbroic soil. Digestibility of food items appears to be an important determinant of diet change from the wet to the dry season in impala and elephants.     

The food habits of wild ungulates in Uganda by analyses of stomach contents

Food eaten by six species of ungulates was studied by analysing stomach contents, using the method developed for faecal analyses. Frequency analyses showed that some herbivore species tend to be selective in their feeding. This suggested that availability and growth form of plants may be important in this respect. The observations agreed with those of other workers, which shows that feeding habits are consistent over large areas. In general, herbivores were classified in three groups with regard to preferences; namely pigs, certain antelope, and buffalo and waterbuck. Comparison of the proportions of epidermal fragments of particular grass species present in stomachs in wet and dry seasons showed that significant seasonal differences exist in the diet of most herbivores. Annuals and most members of the Andropogoneae were present in stomachs in larger proportions during the rains for reasons of availability and palatability. Chloris gayana and Sporobolus pyramidalis were usually present in greater proportions in dry seasons. Differences in the proportions of epidermal fragments of particular plant species present within wet or dry seasons were usually insignificant. A few herbivores, however, showed significant differences within seasons. This indicates that they are sensitive to small changes in plants and that they may have a feeding cycle involving a gradual and regular alternation of plant species. A comparison of the proportions of fragments of the same plant species in different herbivores showed that animal species usually avoided competition by their specialized food habits. There was greater separation in the longer dry season, but competition may have occurred when food supplies were reduced by large herbivores such as buffalo and hippopotamus.     

Diet composition and habitat selection of eland in semi-arid shrubland

This study investigated the diet composition and habitat selection of eland in semi-arid shrubland, dominated by microphyllous and leptophyllous browse species offering low leaf: stem ratios. Browse (succulent, forb and woody species) contributed 94% to the annual diet of eland. The annual proportion of grass in eland diet was low (6%), even though palatable grass species were abundant in habitats favoured by eland. Most grass was eaten in the early wet season when grasses offered young green foliage. Woody species comprising dwarf shrubs and shrubs made up the bulk of the food eaten by eland. In each season, favoured woody species contributed substantial proportions to the diet of eland. Eland used the plateau habitats in the early wet season, but valleys and slopes in the late wet and dry seasons. Habitats favoured by eland contained high abundances of plants of woody species favoured by eland. Chemical analysis indicated that woody species favoured by eland offered lower total fibre contents than other woody species available to eland. The results of the study indicated that eland are browsers that select browse of low fibre content.     

Landscape-scale feeding patterns of African elephant inferred from carbon isotope analysis of feces

The African elephant (Loxodonta africana) is a large-bodied, generalist herbivore that eats both browse and grass. The proportions of browse and grass consumed are largely expected to reflect the relative availability of these resources. We investigated variations in browse (C(3) biomass) and grass (C(4)) intake of the African elephant across seasons and habitats by stable carbon isotope analysis of elephant feces collected from Kruger National Park, South Africa. The results reflect a shift in diet from higher C(4) grass intake during wet season months to more C(3) browse-dominated diets in the dry season. Seasonal trends were correlated with changes in rainfall and with nitrogen (%N) content of available grasses, supporting predictions that grass is favored when its availability and nutritional value increase. However, switches to dry season browsing were significantly smaller in woodland and grassland habitats where tree communities are dominated by mopane (Colophospermum mopane), suggesting that grasses were favored here even in the dry season. Regional differences in diet did not reflect differences in grass biomass, tree density, or canopy cover. There was a consistent relationship between %C(4) intake and tree species diversity, implying that extensive browsing is avoided in habitats characterized by low tree species diversity and strong dominance patterns, i.e., mopane-dominated habitats. Although mopane is known to be a preferred species, maintaining dietary diversity appears to be a constraint to elephants, which they can overcome by supplementing their diets with less abundant resources (dry season grass). Such variations in feeding behavior likely influence the degree of impact on plant communities and can therefore provide key information for managing elephants over large, spatially diverse, areas.     

Diet and distribution of elephant in the Maputo Elephant Reserve, Mozambique

The distribution and diet of the elephants of the Maputo Elephant Reserve were studied using dung counts, satellite tracking and faecal analysis. The results were compared with earlier data from before the civil war in Mozambique. The elephant population decreased during the civil war, but 180 animals still remain. Earlier studies described the elephants as preferring the grass plains. Currently, the elephants prefer the dense forest patches over the high quality forage found in the grass plains. Water salinity affected distribution; elephant dung piles were found closer to fresh water in the dry season. A total of 95 different plant species were identified in the faeces. The percentage of grass was relatively low compared with other studies, increasing at the beginning of the rainy season. At the end of the dry season, elephants concentrated on the few available browse species with young leaves, but generally preferred grass species to browse species. Diet composition was mainly affected by season and less by habitat. The elephants have changed their habitat preference in reaction to poaching, and probably increased the contribution of browse species in the diet. The presence of forest patches has been vital for the survival of the elephants.     

Feeding patterns of sitatunga (Tragelaphus Speki) in the Rushebeya‐Kanyabaha wetland,south western Uganda

Feeding patterns and habits of sitatunga were assessed in Rushebeya‐Kanyabaha wetland between June 2006 and July 2007. Sixty transects were cut at intervals of 250 m along which sitatunga dung piles, habitats used and diet were identified from feeding signs or plant damage. Household interviews were also conducted in villages adjacent to the wetland to understand plants and crops known to be fed on by sitatunga, type of damage, frequency of sitatunga farm visits and their methods to control crop raiding. Sitatunga mostly fed on leaves (60%) and in the wetland edge (WE) habitat (49%). Forty plant species were recorded to be eaten with herbs as majority (33%) and of crops sweet potatoes were most raided. Sitatungas are basically solitary species with 73% of the sightings being of a single individual. They had mornings and late evenings as their movement peaks and preferred to feed on broad leaved plants. There were significant relationships between both habitat use and food preferences with seasons. We predict that because of seasonal food variations, crop raiding would increase and may result into more negative attitudes by farmers to sitatunga. More research on farmers’ sensitization, population census, behaviours and ecotourism are necessary for this species conservation.     

Baboon diet: a five-year study of stability and variability in the plant feeding and habitat of the yellow baboons (Papio cynocephalus) of Mikumi National Park, Tanzania

The habitat and plant feeding of 64 well-habituated, individually identified adult male and female yellow baboons was studied for 5 years at Mikumi National Park, Tanzania. Variation across the years showed that a study of only one or two years would have been incomplete and misleading. The list of baboon food species obtained from Mikumi is considerably larger and more diverse than any previously reported. One to six plant parts were eaten from each of more than 180 species. The 25 most common tree genera all contained species used for food. Of the 50 most common grass, shrub and herb genera, 93% included plant foods. Using months in which a species was eaten during at least one year of the study, 21 staple species were eaten during a mean of 8.86 months and 7 were eaten in all 12 months. Although many foods were from commonly available plant species, 15 such species were only rarely eaten. The number of parts of a species eaten per month and an estimate of the amounts eaten per month both varied with temperature and rainfall, being lowest near the end of the cool, dry season. There were substantial differences from year to year in the timing and amount of food production of many species; nevertheless, the same broad feeding pattern was repeated in each of the 5 years of the study. Despite yearly variation in food availability, 14 or more staples and other common foods were eaten in any given month. If crops of many of these foods were to fail, a large number of less commonly eaten species could be substituted. Baboons are eclectic feeders that appear to be optimizing their diet by selective feeding from among a wide array of available foods in an ever-changing floristic environment.     

Feeding ecology and nutrition of an eastern gorilla group in the Mt. Kahuzi Region (République du Za?re).

An eastern gorilla group of the Mt. Kahuzi region (République du Za?re) was studied over 15 months. Its migration route was determined, and the various biotopes it visited are described. A record was made of its main food plants, and of the plant parts eaten. For nine important food plants the protein content, the concentration of the individual amino acids and the water content were measured for the plant parts eaten and for those not eaten. For some of these plant parts the Na, K, Ca and Mg content were also determined. No general correlation between food selection and one or several of these factors could be found. The development and value of a traditionally determined mixed diet is discussed.     

Analyses of African elephant (Loxodonta africana) diet with various browse and pellet inclusion levels

To more closely simulate the diet of free-ranging elephants, the diet of six (2.4) African elephants (Loxodonta africana) was altered to include more browse and less pelleted complete feed (5% total diet). Dietary proximate compounds, minerals, vitamins A (and carotenoids), D and E, and fatty acids were analyzed on pelleted diet items and forages including hay, grass, and browse. A total of 42 browse species were offered over 1 year with an average total diet inclusion of 5.2% (dry matter basis) per day. Dietary Na and Se were low while Fe and Mn were high compared to published intake levels for elephants. Analyzed nutrients within browse varied widely among seasons and species. Ingredient analyses were used to create predicted elephant nutrient intake for (a) the current diet, (b) a diet excluding pellets, and (c) a diet excluding pellets and providing browse at doubled levels. Formulated diets excluding pellets had lower mineral levels than the current diet and doubled browse did not alter mineral inclusions of concern. This study provides seasonal data on the nutrient levels of Southeastern browse species important for various pachyderm and herbivorous species. Predicted nutrient intake with new diet scenarios does not support the exclusion of pellets in the diets of African elephants without greater browse quantity availability, strict diet management, or additional supplements.     

PRELIMINARY OBSERVATIONS ON FOOD HAWITS OF GERENUK IN TSAVO NATIONAL PARK, KENYA

In the context of widespread vegetation changes in Tsavo National Park, food habits of gerenuk are being investigated; the present paper gives an account of the results obtained during the first year of the study. Feeding of free-ranging gerenuk was observed from a landrover in two study areas with different vegetation types. Plant species eaten were determined in the field or collected for identification. Gerenuk feed almost exclusively on leaves, shoots, flowers, and a few fruits of trees and shrubs, as well as some climbers and vines, the latter mainly during the rainy seasons. No small herbs or grass were found to be eaten. The composition of the diet differed considerably between the two study areas, largely as a result of differences in the available vegetation. Seasonal variations in the diet are brought about mainly by variations in the availability of different food plants, notably the ratio between deciduous and evergreen species at different seasons. On the basis of a preliminary quantitative survey of the vegetation in the study areas, actual preferences have been evaluated. Some common plant species were found to be rejected altogether, although they are eaten by other browsing animals. A total of 68 plant species has so far been recorded as food plants, indicating that gerenuk are able to utilize a wide range of plants. In view of this adaptability, and of the abundance of preferred food plants in the study areas, the vegetation changes in Tsavo National Park do not, at present, appear to endanger the continued existence of the gerenuk.     

Foraging ecologies of giraffe (Giraffa camelopardalis reticulata) and camels (Camelus dromedarius) in northern Kenya: effects of habitat structure and possibilities for competition?

The foraging ecologies of reticulated giraffe (Giraffa camelopardalis reticulata) and domestic camels (Camelus dromedarius) were examined in the Laikipia District of Kenya, where these species have recently become sympatric. Camels increased popularity in the region has lead to concerns about their environmental impacts and possible competition with wild giraffe for resources. We gathered foraging data on both species using 2‐min group scans that recorded feeding heights and plant food preferences. Transects sampled the vegetation in areas where foraging observations were recorded. Giraffe females feed at lower elevations than males, while female camels feed below both sexes of giraffe. There was very little observed overlap in food preferences between the species. However, habitat type has an effect on foraging ecologies of both giraffe sexes, but habitat did not influence camel foraging. Camel herder husbandry techniques also influence camel foraging dynamics. These findings have important implications in achieving the twin objectives of wildlife conservation and pastoralist livestock production in northern Kenya.     

Sighting frequency and food habits of the leopard tortoise, Geochelone pardalis, in northern Tanzania

Sighting frequency and food habits of the leopard tortoise (Geochelone pardalis) were studied in northern Tanzania from October 1993 to June 1996. Sighting frequency varied significantly between protected (0.22 mhr^?1) and unprotected sites (0.59 mhr^?1), and between Arusha (0.27 mhr^?1) and Serengeti sites (0.56 mhr^?1). The tortoise diet comprised mostly plants (97.8%) and rarely inorganic matter (2.2%). A total of 47 plant species from 21 families was eaten. Forbs made up 74.5% of the plant items and monocots the remainder. Succulents contributed 51.0% of the plant items eaten while grasses and legumes accounted for 16.8% and 13.5%, respectively. Some plant items were eaten more frequently than their occurrence in the habitats.     

蒙古野驴的秋季食性分析

2006 年9 月在新疆卡拉麦里山有蹄类野生动物保护区内采集了25 堆蒙古野驴粪便和10 科共29 种植物标本,采用粪便显微组织学分析方法分析了蒙古野驴的秋季食性,并初步探讨了其食性与周围环境的关系。结果表明,蒙古野驴秋季食性广, 共采食8 科26 种植物。这些植物按照其在食物组成中的比例可分为3 大类:主要食物为梭梭、针茅、驼绒藜, 共占食物组成的61.3% ;常采食植物为柽柳、角果藜、蒿、琵琶柴、芨芨草等11种,共占食物组成的33.3%; 少见采食的植物为盐爪爪、獐毛、顶羽菊、黑果枸杞、里海盐爪爪等12 种,共占食物组成的6.7% 。按科别而论,蒙古野驴采食最多的是藜科植物,其次是禾本科植物。从被采食植物的分布区域分析,其采食区域广阔,包括了保护区内所有的生境类型。      

云南思茅亚洲象对栖息地的选择与利用

以思茅市境内栖居的一个由5 头雌象(3 头成年体, 1 头亚成体, 1 头幼体) 组成的象群为研究对象, 利用痕迹追踪、样线调查和村庄调查等方法对野生亚洲象的栖息地选择和行为进行了初步研究。在栖息地中共记录到野生高等植物457 种, 组成5 种植被类型。旱季象群的活动区域面积是35.67 km² , 该活动区域中有3 个核心活动区, 面积分别是3.65 km² , 2.79 km² 和3.29 km² , 象群对此3 个活动核心区域循环利用; 在旱季亚洲象经常取食19种野生植物, 其中主要取食的有8 种, 还取食7 种农作物, 对农作物有一定依赖性, 这种依赖的程度随着农田周围森林中野生食物丰富程度的增加而降低; 在季雨林中亚洲象主要取食的植物种类最丰富。雨季象群的活动区域面积是18.42 km² , 该区域中只有1 个核心活动区, 面积9.08 km² 。雨季亚洲象只取食5 种野生植物, 另取食5 种农作物, 农作物为其雨季主要食物。研究结果表明, 思茅地区亚洲象栖息地中的野生食物可能不足, 人类活动对亚洲象的生存干扰较为严重, 亚洲象的行为表现出对栖息地内食物条件和人类干扰的适应。建议尽快遏止日益严重的栖息地片断化趋势, 恢复自然植被并为亚洲象提供充足的野生食物是保护该物种的关键。