M. Elizabeth Rogers

Gorilla diet in the Lope Reserve, Gabon: A nutritional analysis

SummaryThe results of an analysis of gorilla diet in the Lopé Reserve, Gabon are presented. Samples were assayed for nutrients and plant secondary compounds (total phenols, condensed tannins and alkaloids) in an attempt to explain gorilla food choice. The diet is the most diverse so far analysed for gorillas; it seems to be a balance between sugary fruit, proteinaceous leaves, and relatively fibrous stems. Most fruits and herbaceous stems are succulent, but some drier, fibrous fruit and bark is also consumed. Seeds are another component of the diet, including unripe ones. Fruit, seeds, leaves and bark may all contain very high levels of total phenols and condensed tannins; but all herbaceous stems assayed contain low levels of these compounds. Alkaloids are not apparently a significant component of gorilla foods, and may be avoided. Gorillas at Lopé tend to avoid fatty fruit, and select leaves which are high in protein and low in fibre compared to the general vegetation. When fruit and preferred young leaves are scarce, proteinaceous barks and mature leaves, and sugary pith, are important sources of nutrients. We conclude that gorillas exploit the broad frugivore niche in West African lowland forests, and are part of the frugivore community there. What distinguishes them is their ability to eat large fibrous fruit, mature leaves and stems, and to overcome high levels of phenolics (we use “phenolics” as an umbrella term for both total phenols and condensed tannins). Gorilla diet at Lopé overlaps greatly with that of sympatric, frugivorous, primates, and resembles more closely that of chimpanzees than it does gorilla diet studied elsewhere in Africa.

Snow leopard Panthera uncia predation of livestock: An assessment of local perceptions in the Annapurna Conservation Area, Nepal

Abstract Public attitudes towards snow leopard Panthera uncia predation of domestic livestock were investigated by a questionnaire survey of four villages in snow leopard habitat within the Annapurna Conservation Area, Nepal. Most local inhabitants were subsistence farmers, many dependent upon yaks, oxen, horses and goats, with an average livestock holding of 26.6 animals per household. Reported losses to snow leopards averaged 0.6 and 0.7 animals per household in two years of study, constituting 2.6% of total stockholding but representing in monetary terms almost a quarter of the average annual Nepali national per capita income. Local people held strongly negative attitudes towards snow leopards and most suggested that total extermination of leopards was the only acceptable solution to the predation problem. Snow leopards were reported to be killed by herdsmen in defence of their livestock. The long-term success of snow leopard conservation programmes may depend upon the satisfactory resolution of the predation conflict. Some possible ways of reducing predation losses are also discussed.

A case study of a plant-animal relationship: Cola lizae and lowland gorillas in the Lope Reserve, Gabon

The fiuits of Cola lizae, an endemic tree with a limited geographical distribution, have been a major food source for lowland gorillas in the Lope Reserve during part of each year over a six-year period. Faecal analysis indicated that 11,000-18,000 Cola seeds km-2 were deposited by gorillas during the 4-month season in 1989. Gorillas are the only important dispersers of this species: other primates consume the succulent mesocarp, but do not swallow the large seed; elephants do not eat Cola fruits. Observations of Cola seeds in gorilla faeces showed a very high germination rate and, despite initial high mortality, 18%/ of seedlings still survived six months after deposition. Survival of seedlings was significantly better in faeces left at nest-sites than in other areas of the forest: 40% of seedlings were viable at nest-sites six months after deposition. This suggests that the open areas of forest, preferred by gorillas as nest-sites, are advantageous to the propagation of this species.

Ten days in the life of a Mandrill horde in the Lopé reserve, Gabon

Mandrills have long been known to form large aggregations in the wild, but it has proved difficult to obtain detailed information on the socioecology of these groups. An unusually large (>600) horde of mandrills was followed for ten days during the 1995 dry season in Central Gabon, and data were collected on group composition and ecology while the mandrills were in an area of forest‐savanna mosaic habitat in the north of the Lopé Reserve. Three separate counts of most of the group showed that fully coloured “fatted” adult males were present throughout the horde at a mean ratio to other individuals of 1:21. Paler “non‐fatted” adult and sub‐adult males were also distributed throughout. Mandrill diet over the ten days consisted mainly of insects, seeds from forest trees, and leaves or stems of understory herbaceous plants. Feeding was extremely selective, with most food items consumed in a much higher proportion than would be predicted from their relative availability. Ranging data also showed that the mandrills foraged preferentially in certain forest types within the forest‐savanna mosaic, namely in Marantaceae and Rocky Forest. It is suggested that one reason why mandrills pass through gallery forests and forest‐savanna mosaic in the dry season in the Lopé Reserve is because they find fruit there from preferred species, which are no longer fruiting in the main forest block, thus allowing them to maintain the fruit component of their diet at a time of fruit shortage.

Tandem integration of complete and defective SV40 genomes in mouse-human somatic cell hybrids

We have analyzed the arrangement of SV40 DNA sequences integrated in human chromosome 7 in two lines of mouse-human somatic cell hybrids: one containing only one human chromosome 7 per cell and the other containing an average of about three. We found that the integration site differs in both the viral and host sequences in the two clones. However, the sites of integration into the several copies of human chromosome 7 of one clone are identical. Each chromosome 7 in both clones carries approximately six viral genomes tandemly linked. Some of these genomes lack about 20% of the DNA from the late region, including the Eco RI site.

Gorillas and seed dispersal in the Lope Reserve, Gabon. I: Gorilla acquisition by trees

Recent studies have shown that western lowland gorillas (Gorilla gor- illa gorilla Savage & Wyman) are highly frugivorous and expel in their dung viable seeds of many fruit species they consume. As part of a wider study of their role as seed dispersers in tropical rain forest, the importance of gorillas as consumers of three species of tropical tree was investigated. The species studied were Ganophyl- lum giganteum (Sapindaceae), Cola lizae (Sterculiaceae) and Uapaca guineensis (Euphorbiaceae). Gorillas swallowed large quantites of seeds of these species whenever they were available, and removed a considerable proportion of the crop from trees they visited. The differences in abundance and distribution of these trees, and their varied dispersal strategies influenced the quantity of seeds that was removed by gorillas. Uapaca can be seen as having a generalist fruiting strat- egy, with a wide range of consumers, whereas the other species are more specialist, gorillas being the principal dispersers. Compared to other consumers, this study showed that gorillas provided potentially high quality dispersal because: (i) they were reliable visitors to trees of these species; (ii) they swallowed and dispersed large numbers of seeds; (iii) they treated seeds benignly and often deposited them in sites favourable for establishment.

Food Items Consumed by White-headed Langurs in Fusui, China

We studied the socioecology of white-headed langurs (Trachypithecus leucocephalus) from September 1997 to September 1998 in Fusui Precious Animal Reserve, SW Guangxi, China. We collected data on climate, phenology of food plant species, and foods consumed by langurs living in habitats with different levels of human disturbance. Feeding records showed that the most food is from less common plant species. Young leaves were the staple food item in all langur groups, and consumption correlates with availability. Consumption of mature leaves is not significantly correlated with their availability, but the langurs fed on them, and other food items such as fruits and seeds, when the availability of young leaves was low. Langurs in different areas had broadly similar diets, but they varied most in the proportion of supplementary items such as fruit. Groups in more disturbed habitat did not increase the overall proportion of mature leaves in their diet, but instead maintained their intake of young leaves from a greater diversity of species, and incorporated more immature fruit. Conservationists should direct efforts toward protection of rare plant species providing preferred food items, particularly supplementary foods at times when, and in areas where, preferred food items are less available.

Habitat quality and range use of white-headed langurs in Fusui, China.

The socioecology of white-headed langurs (Trachypithecus leucocephalus) was studied in Fusui Precious Animal Reserve, Guangxi, China, in 1997/1998. Habitat quality was classified according to the level of human disturbance. Plant species diversity increased with habitat quality. Important foods for the langurs occurred more in high-quality habitat. Home range size varied from 28 to 48 ha, and the home range area per individual decreased as habitat quality increased. Small polygynous langur groups had poorly defended ranges, but large groups defended their ranges intensively. Only harem males were involved in group defence, apparently competing for females by defending their habitat. High-quality habitat was more attractive to females; accordingly, group size increased significantly with habitat quality.

Are Limestone Hills a Refuge or Essential Habitat for White-Headed Langurs in Fusui, China?

AbstractWe studied the ecology of white-headed langurs (Trachypithecus leucocephalus) in Fusui Precious Animal Reserve, Guangxi, China, in 1997/1998 and conducted surveys of them in 1996–1997 and 2003. We collected data on vegetation fragments and the activities of white-headed langurs at different levels on limestone hills. The langurs selected less fragmented habitats with less human disturbance. They spent ca. 60% of the day at lower levels of the hills during maintenance activities, including feeding. When humans were absent, the langurs even came to the ground. The hills themselves were used as a refuge from human disturbance but were not otherwise essential habitat. Results of this study have implications for improving conservation management for the langurs.

Seasonal pattern in group size and population composition of blue sheep in Manang, Nepal

Blue sheep (Pseudois nayaur) are the principal prey of the endangered snow leopard (Panthera uncia) in the Himalayas and adjacent ranges. We studied group size and population composition of blue sheep in Manang District, Annapurna Conservation Area, Nepal. Overall mean group size was 15.6 (SE = 1.3), but it varied seasonally (P < 0.001), with significantly smaller groups in winter than in other seasons. Mixed groups were most numerous in all seasons, and there was no evidence of sexual segregation. Yearling sex ratio (93.7 M:100 F) did not vary seasonally, nor did the ratio deviate from parity. Adult sex ratio showed a seasonal pattern favoring males post-parturition but female-biased during the rut and pre-parturition. Seasonal variation in sex-specific mortality is offered as a plausible explanation for the observed pattern in adult sex ratio.