Intestinal parasites and bacteria of mountain gorillas (Gorilla beringei beringei) in Bwindi Impenetrable National Park, Uganda

A survey in 1994 examined intestinal helminths and bacterial flora of mountain gorillas (Gorilla beringei beringei) in Bwindi Impenetrable National Park, Uganda. Parasites and bacteria were identified to genus in the feces of two groups of tourist-habituated and one group of non-tourist-habituated mountain gorillas. Eggs were identified as those of an anoplocephalid cestode, and nematode eggs representative of the genera: Trichuris, Ascaris, Oesophagostomum, Strongyloides, and Trichostrongylus. This is the first report of Ascaris lumbricoides-like eggs in mountain gorillas. Fecal samples (n=76) from all groups contained helminth eggs, with strongyle eggs and anoplocephalid eggs being the most common. Salmonella and Campylobacter were found in both gorilla groups. Regular long-term non-invasive fecal monitoring of the populations of mountain gorillas is essential for the prevention and identification of potential health threats by intestinal parasites and bacteria in this highly endangered subspecies.This revised version was published online in April 2005 with corrections to the cover date of the issue.     

Natural regeneration and ecological recovery in Bwindi Impenetrable National Park, Uganda

This study tests the justification for displacement and compensation of persons in a previously settled land for natural ecological recovery, and helps in the understanding of patch dynamics in a semi‐mountain tropical rain forest environment. The study area comprised parts of the Mbwa River Tract in Bwindi Impenetrable National Park in Uganda that had been settled and cultivated for at least 20 years prior to park reclassification. The extent, state and speed of regeneration of the cleared forest (CF) after resettlement were not known. There was therefore need for a baseline study as prerequisite for future ecological monitoring of forest recovery. Strip‐plots at 200 m intervals running across the tract were therefore established for this study. 1.17 km² of forest had been cleared for cultivation in the tract and regeneration in adjacent forest (MF) was better than in the CF, based on the abundance of seedlings. The CF was more diverse in species composition than the MF, and with predominantly pioneer tree species growing. The CF was ecologically important as a water catchment area and a habitat for several animal species, and there were indications that it was heading for ecological recovery.     

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.     

Home Range and Frugivory Patterns of Mountain Gorillas in Bwindi Impenetrable National Park,Uganda

Mountain, western, and Grauer's gorillas exhibit broad differences in ecological patterns with western gorillas eating more fruit and having larger home ranges than their largely folivorous counterparts in the Virunga Volcanoes. We studied the home range and frugivory patterns of one group of Gorilla beringei beringei in the little-studied population of Bwindi Impenetrable National Park, Uganda, to compare with other populations and to investigate whether there was any relationship between patterns of frugivory and home range size. During the 3-year study, the gorillas ate 16 species of fruit on 27% of observation days. There was high variability in frugivory among the 3 years and no consistent seasonal pattern. Annual home range size was ca. 21 km² for Years 1 and 2, and it increased dramatically to 40 km² in Year 3. Home range size varied considerable between months and seasons, but there is no clear relationship between occurrence of fruit-eating and home range size. The group exhibited more fruit-eating and a larger home range size those ofthe gorillas in the Virunga Volcanoes. Their home range size is comparable to that of western gorillas, though Bwindi gorillas consumed less fruit. Home range size and utilization by all gorillas probably depends on a complex relationship between the distribution and abundance of both fruit and herbaceous vegetation and social factors such as male mating tactics.     

Behavioral Ecology of Sympatric Chimpanzees and Gorillas in Bwindi Impenetrable National Park,Uganda: Diet

Via a field study of chimpanzees (Pan troglodytes schweinfurthii) and gorillas (Gorilla gorilla beringei) in Bwindi Impenetrable National Park, Uganda, we found that their diets are seasonally similar, but diverge during lean seasons. Bwindi chimpanzees fed heavily on fruits of Ficus sp., which were largely ignored by the gorillas. Bwindi gorilla diet was overall more folivorous than chimpanzee diet, but was markedly more frugivorous than that of gorillas in the nearby Virunga Volcanoes. During 4 mo of the year Bwindi gorilla diet included more food species than that of the chimpanzees. Three factors in particular—seasonal consumption of fibrous foods by gorillas, interspecific differences in preferred fruit species, and meat consumption by chimpanzees—contributed to dietary divergence between the two species. When feeding on fruits, gorillas ate Myrianthus holstii more frequently than chimpanzees did, while chimpanzees included more figs in their annual diet. Chimpanzee diet included meat of duikers and monkeys; gorilla frequently consumed decaying wood.     

Medical Survey of the Local Human Population to Determine Possible Health Risks to the Mountain Gorillas of Bwindi Impenetrable Forest National Park,Uganda

There has been increasing contact between mountain gorillas (Gorilla gorilla beringei) and the human population surrounding Bwindi Impenetrable Forest National Park (BIFNP) in Uganda. Due to the close taxonomic relationship between humans and gorillas there is potential for disease transmission between them. Preventing the introduction or spread of transmissible diseases to the gorillas is essential to protect them. We interviewed 301 villagers living in close proximity to BIFNP with a medical questionnaire in July, 2000. We collected information on demographics, vaccination and health history, and human/gorilla interaction. Our objectives were to estimate the prevalence of several diseases in the human population and to evaluate the risk of anthropozoonotic transmission from humans to gorillas. We found a high prevalence of disease symptoms such as coughing (72.1%) and fever (56.1%) compatible with acute infectious diseases; over half of the respondents (59.1%) had a specific disease diagnosis within the 6 mo preceding the study. We compared villagers who had visual contact with gorillas in the 6 mo preceding the study (53.5%) to villagers who had no visual contact (46.5%). Men were 2.3 times more likely than women to have visual contact with gorillas. In general, the frequency of disease history and symptoms was similar for people with and without contact. The high prevalence of acute infectious diseases in the population surrounding BIFNP and the high rate of contact with gorillas creates the potential for anthropozoonotic disease transmission.     

Intrapopulation differences in ant eating in the mountain gorillas of Bwindi Impenetrable National Park, Uganda

Variability in ant eating has been observed in several populations of eastern and western gorillas. We investigated the occurrence of ant (Dorylus sp.) eating in two groups of mountain gorillas (Gorilla beringei beringei) with overlapping home ranges within Bwindi Impenetrable National Park, Uganda from September 2001 to August 2002. We calculated the frequency of ant eating by an indirect method of analyzing fecal samples from silverbacks, adult females, and juveniles. One group consumed ants significantly more often than the other (3.3 vs 17.6% of days sampled). Furthermore, the group that consumed ants more often also consumed them on a seasonal basis (September–February monthly range: 0–8%; March–August monthly range: 30–42.9%). Finally, females and juveniles of this group consumed ants significantly more often than did the silverback (total samples containing ants: silverback, 2.1%; adult female, 13.2%; juvenile, 11.2%). Differences in ant eating between groups are likely due to variability in use of habitats where ants occur (particularly secondary forests). Surveys of ant densities in differing habitats, nutritional analysis of ants, and quantification of the amount of ants in their diets are necessary to understand if ant consumption is due to availability, nutritional value, group traditions, or taste preference.     

Lianas and Livelihoods: The Role of Fibrous Forest Plants in Food Security and Society around Bwindi Impenetrable National Park,Uganda

Lianas and Livelihoods: The Role of Fibrous Forest Plants in Food Security and Society around Bwindi Impenetrable National Park, Uganda This paper documents the role that fibrous plants play in rural economies of farming communities in southwestern Uganda. Thirty-five plant species from 20 plant families are used to weave baskets, stretchers, granaries, and protective coverings for clay pots. These products play a crucial role in local culture, the local economy, and social institutions as well as in food security due to their use in carrying, processing, or storing crops. Lianas (Loeseneriella apocynoides, Smilax anceps, and to a lesser extent, Cyphostemma bambuseti, Flabellaria paniculata, Hippocratea odongensis, Salacia elegans, and Urera hypselodendron) are the most important plant life-forms used, followed by bamboo (Sinarundinaria alpina). The extent of use of plant species for granaries varied significantly with altitude, vegetation type, and land-cover across the wide altitudinal range of the study area (1,440–2,600 m asl). Granaries used by farmers at lower altitudes used a higher diversity of species compared to those at a higher altitude, where 82% of granaries were constructed from bamboo (Sinarundinaria alpina). Tightly woven, durable granaries are important for food storage and therefore to the food security and sustainable livelihoods of subsistence farmers. Where length, strength, and durability of weaving fibers were required, such as for stretchers (engozi) used as local “ambulances,” only two liana species were favored. The most commonly used species was the forest liana Loeseneriella apocynoides (Celastraceae), used for up to 77% of engozi stretchers and 83% of tea-picking baskets. While most species are abundant and can be sustainably harvested, L. apocynoides is overexploited, posing problems for local people and the national park.     

Observations on the breeding behaviour of the Stripe‐breasted tit (Parus fasciiventer) in Bwindi Impenetrable National Park,Uganda

The motivation of this study was to investigate some hitherto unknown information on the breeding ecology of the Stripe‐breasted Tit (Parus fasciiventer) in Bwindi Impenetrable National Park, south‐western Uganda. Parus fasciiventer is one of the least studied and endemic bird species restricted to the montane forests of the Albertine Rift. Regionally, it is classified as near‐threatened. The study was carried out around the Institute of Tropical Forest Conservation Ruhija camp and the period of study was from January to June 2003. Data were generated through direct observation at the nest box sites of three active nests. Each of the nest boxes was monitored from the time of nest building to the time the chicks fledged. Results and comparative assessments from this study demonstrate that P. fasciiventer, compared with its temperate congeners like Great Tits (Parus major), Marsh Tits (Parus palustris), Crested Tits (Parus cristatus), Coal Tits (Parus ater) and Blue Tits (Parus caeruleus), raised small broods and had longer nestling period. The findings further revealed that the species is capable of raising more than one brood in a single breeding season and provide further evidence that it is a cooperative breeder. Parents participated equally in raising the young, an indication of pure parenting in the species.     

Cryptosporidium sp. and Giardia sp. infections in mountain gorillas (Gorilla gorilla beringei) of the Bwindi Impenetrable National Park, Uganda

For conservation purposes and because of growing ecotourism, some mountain gorilla (Gorilla gorilla beringei) populations have been habituated to humans. Fecal specimens (n = 100) of nonhabituated and human-habituated gorillas (5 populations; 6 age classes) were tested for Cryptosporidium sp. oocysts and Giardia sp. cysts by conventional staining and immunofluorescent antibody (IFA). Cryptosporidium sp. infections (prevalence 11%) were not restricted to very young gorillas but were observed in 3-yr-old to >12-yr-old gorillas; most of the infections (73%) occurred in human-habituated gorillas. The prevalence of Giardia sp. infections was 2%; 1 nonhabituated gorilla was concomitantly infected. Oocysts of Cryptosporidium sp. in the gorilla stools were morphologically, morphometrically, and immunologically undistinguishable from a bovine isolate of Cryptosporidium parvum oocysts. Mean concentration of Cryptosporidium sp. oocysts and Giardia sp. cysts in gorilla stools was 9.39x10(4)/g, and 2.49x10(4)/g, respectively. There was no apparent relationship between oocyst concentration and gorilla age, sex, or habituation status. Most Cryptosporidium sp. infections found in gorillas with closest proximity to people may be a result of the habituation process and ecotourism. This study constitutes the first report of Cryptosporidium sp. infections in the family Pongidae, in the free-ranging great apes, and in the species of gorilla.     

Local environment,not local adaptation,drives leaf‐out phenology in common gardens along an elevational gradient in Acadia National Park,Maine

Premise of the Study

Climate‐driven changes in phenology are substantially affecting ecological relationships and ecosystem processes. The role of variation among species has received particular attention; for example, variation among species’ phenological responses to climate can disrupt trophic interactions and can influence plant performance. Variation within species in phenological responses to climate, however, has received much less attention, despite its potential role in ecological interactions and local adaptation to climate change.

Methods

We constructed three common gardens across an elevation gradient on Cadillac Mountain in Acadia National Park, Maine, to test population‐level responses in leaf‐out phenology in a reciprocal transplant experiment. The experiment included three native species: low bush blueberry (Vaccinium angustifolium), sheep's laurel (Kalmia angustifolia), and three‐toothed cinquefoil (Sibbaldiopsis tridentata).

Key Results

Evidence for local adaptation of phenological response to temperature varied among the species, but was weak for all three. Rather, variation in phenological response to temperature appeared to be driven by local microclimate at each garden site and year‐to‐year variation in temperature.

Conclusions

Population‐level adaptations in leaf‐out phenology appear to be relatively unimportant for these species in Acadia National Park, perhaps a reflection of strong genetic mixing across elevations, or weak differences in selection on phenological response to spring temperatures at different elevations. These results concur with other observational data in Acadia and highlight the utility of experimental approaches to understand the importance of annual and local site variation in affecting phenology both among and within plant species.     

Forest gap formation and closure along an altitudinal gradient in Tongariro National Park,New Zealand

24 treefall gaps accumulated over a 10 year period along an altitudinal transectcovering 4.6ha on Mt. Hauhungatahi, Tongariro National Park, New Zealand were described quantitatively in terms of the area of damage (‘expanded gap’), the canopy opening (‘Tight-gap’) and the size of the root mound. Tree mortality and branch loss following cyclone Bola, 1988, were recorded. In each gap saplings were ranked by species according to their vigour. Pre-gap and post-gap vertical and horizontal branch growth rates were calculated. Effects in the subalpine forest (> 1050 m) were compared with those in the montane zone. Tree mortality was highly episodic, associated with major storms, and patchy. Falling canopy trees destroyed, on average, 1.3 additional trees (> 10 cm diameter at 1 m). About half the trees were uprooted and the remainder broken off. Uprooted angiosperm (canopy) trees frequently resprouted from their bases, gymnosperms rarely. Expanded gap area averaged 56 m² in the sub-alpine forest and 88 m² in the montane zone. Median expanded gap areas were about twice those of light gaps. Gap size frequency distribution was highly skewed. The largest gap was formed by a single Dacrydium cupressinum which destroyed six other trees creating a gap of ca. 0.03 ha. Expanded gaps, light gaps, and root mounds comprised 4.5, 2.8 and 0.1 % of the forest area in the sub-alpine zone, and 3.8, 2.5 and 0.06 % in the montane forest. These values represent 10 years of accumulation, and imply light gap ‘return times’ of 360 years for the sub-alpine and 400 years for the montane forest. These periods are in agreement with the known longevities of the canopy and emergent trees. Vertical shoot growth rate was about twice that in the horizontal plane, and both increased following gap formation. The relative increase was greatest in the subalpine forest. Using the measured growth rates it is estimated that gaps of median dimensions are filled by lateral extension growth in 31–44 yr. Saplings require longer to reach the mean canopy height and consequently require large (multiple tree) gaps or sequential gap events.     

Variations in sexual and asexual reproduction of Scirpus mariqueter along an elevational gradient

In order to assess the importance of sexual and asexual reproduction during the life history of Scirpus mariqueter, its reproductive and growth characters were concurrently examined along an elevational gradient (from low elevation to high elevation). The proportions of flowering shoot and inflorescence mass, seed : flower ratio and seed weight were used to quantify the investment in sexual reproduction. The proportions of current-year shoot and rhizome mass were used to quantify the investment in asexual reproduction, and the proportion of corm mass was used for growth, respectively. It was found that vegetative propagation predominated at low elevation, whereas sexual reproduction predominated at high elevation; and that sexual reproduction increased with declining asexual reproduction along the gradient. The results suggest that asexual reproduction is relatively favored in the early life stage, whereas sexual reproduction is favored when the population becomes mature and aged, probably because of the functional differentiation between the two reproductive types. Sexual productive characters (i.e. the proportions of flowering shoot and inflorescence mass) were negatively correlated to both growth and asexual reproductive characters along the gradient, indicating there might exist some trade-offs among growth, sexual and asexual reproduction during the life history. However, no obvious pattern was found between asexual reproductive characters and growth characters along the elevational gradient, possibly because of the varied relationships between them at different life stages. The variations in sexual and asexual reproduction in the species and the relationship between them are thought to be of great significance for local population growth, species persistence and evolution.