Search

Objectives: The critically endangered Grauer's gorilla (Gorilla beringei graueri) has experienced an estimated 77% population decline within a single generation. Although crucial for informed conservation decisions, there is no clear understanding about population structure and distribution of genetic diversity across the species' highly fragmented range. We fill this gap by studying several core and peripheral Grauer's gorilla populations throughout their distribution range. Materials and Methods: We generated genetic profiles for a sampling of an unstudied population of Grauer's gorillas from within the species' core range at 13 autosomal microsatellite loci and combined them with previously published and newly generated data from four other Grauer's gorilla populations, two mountain gorilla populations, and one western lowland gorilla population. Results: In agreement with previous studies, the genetic diversity of Grauer's gorillas is intermediate, falling between western lowland and mountain gorillas. Among Grauer's gorilla populations, we observe lower genetic diversity and high differentiation in peripheral compared with central populations, indicating a strong effect of genetic drift and limited gene flow among small, isolated forest fragments. Discussion: Although genetically less diverse, peripheral populations are frequently essential for the long-term persistence of a species and migration between peripheral and core populations may significantly enrich the overall species genetic diversity. Thus, in addition to central Grauer's gorilla populations from the core of the distribution range that clearly deserve conservation attention, we argue that conservation strategies aiming to ensure long-term species viability should include preserving peripheral populations and enhancing habitat connectivity. [ABSTRACT FROM AUTHOR]

In 2007, we detected human herpes simplex virus type 1, which caused stomatitis, in a juvenile confiscated eastern lowland gorilla (Gorilla beringei graueri) that had a high degree of direct contact with human caretakers. Our findings confirm that pathogens can transfer between nonhuman primate hosts and humans. [ABSTRACT FROM AUTHOR]

Molecular studies have demonstrated a deep lineage split between the two gorilla species, as well as divisions within these taxa; estimates place this divergence in the mid-Pleistocene, with gene flow continuing until approximately 80,000 years ago. Here, we present analyses of skeletal data indicating the presence of substantial recent gene flow among gorillas at all taxonomic levels: between populations, subspecies, and species. Complementary analyses of DNA sequence variation suggest that low-level migration occurred primarily in a westerly-to-easterly direction. In western gorillas, the locations of hybrid phenotypes map closely to expectations based on population refugia and riverine barrier hypotheses, supporting the presence of significant vicariance-driven structuring and occasional admixture within this taxon. In eastern lowland gorillas, the high frequency of hybrid phenotypes is surprising, suggesting that this region represents a zone of introgression between eastern gorillas and migrants from the west, and underscoring the conservation priority of this critically endangered group. These results highlight the complex nature of evolutionary divergence in this genus, indicate that historical gene flow has played a major role in structuring gorilla diversity, and demonstrate that our understanding of the evolutionary processes responsible for shaping biodiversity can benefit immensely from consideration of morphological and molecular data in conjunction. [ABSTRACT FROM AUTHOR]

We describe the diet of a semihabituated group of Grauer's gorillas (Gorilla beringei graueri) inhabiting the montane forest of Kahuzi-Biega National Park, Democratic Republic of Congo, based on direct observations, feeding remains in their fresh trails, and fecal samples collected over 9 yr. We examined fruit availability in their habitat; consumption of fruit, vegetative, and animal food; and daily intake of vegetative plant food using a transect, fruit monitoring trails, fecal analysis, and tracing of the animal's daily trails between consecutive nest sites. The fruit food repertoire of Kahuzi gorillas resembles that of western and eastern lowland gorillas inhabiting lowland tropical forests, while their vegetative food repertoire resembles that of mountain gorillas inhabiting montane forests. Among 236 plant foods (116 species), leaves, pith, and barks constitute the major parts (70.2%), with fruit making up the minor part (19.7%). About half (53.2%) of the total fecal samples included fruit remains. The gorillas used leaves, stems and other vegetative plant parts as staples. Their fruit intake was similar to that reported for mountain gorillas in Bwindi. They ate animal foods, including earthworms, on rare occasions. Variation in fruit consumption was positively associated with variation in fruit production. The gorillas ate fig fruits frequently; fig intake is positively correlated with that of other fruits, and figs were not fallback foods. They relied heavily on bamboo shoots on a seasonal basis; however, no bamboo shoots were available for several years after a major flowering event. Our results support the argument that variation in gorilla diets mostly reflects variation in vegetational composition of their habitats. [ABSTRACT FROM AUTHOR]

Abstract The mitochondrial DNA D-Loop region was sequenced, analyzed and used as a molecular marker for populations of chimpanzee (Pan troglodytes), bonobo (P. paniscus) and gorilla (Gorilla gorilla and G. beringei), and also compared with data previously reported for these taxa. In Gorilla, a main disjunction between western (G. gorilla) and eastern (G. beringei, including G. b. graueri) species was observed, as well as high mitochondrial diversity within the western species. The genetic distance values within G. gorilla (0.14) were higher than those between subspecies (eastern lowland and mountain 0.12). Likewise, values of genetic diversity within this species (0.05) were higher than those between species (western and eastern lowland gorilla 0.04). Similarly, in genus Pan a main differentiation between western (P. t. verus) and central forms (P. t. troglodytes and P. t. schweinfurthii) was observed. The obtained values of genetic distance and genetic diversity revealed that the central subspecies are closer to each other than either of them is to the western one, while bonobos composed a distinct clade that expresses a well-defined specific identity. The current distribution, phylogeny and levels of genetic diversity in African great ape populations are consistent with the hypothesis that Pleistocene climatic events led to cyclical periods of isolation in forest refugia followed by expansion and dispersal. The implications of this high level of genetic diversity for taxonomic classification, wildlife management and conservation are discussed. [ABSTRACT FROM AUTHOR]

Methods for the identification of the sex and species of individuals from samples non-invasively taken from humans and gorillas were established. Amplification of a segment of amelogenin (AMG), which is an X–Y homologous gene, using two pairs of primers from human AMG, revealed both X- and Y-specific bands. The possibility of sex identification was examined by typing the AMG gene using hair and fecal samples from captive western lowland gorillas ( Gorilla gorilla gorilla) in Japan and hair samples from wild eastern lowland gorillas ( Gorilla beringei graueri) in the Kahuzi-Biega National Park, Democratic Republic of Congo, which were sexed by direct observation. Species-specific bands of AMG in gorillas and humans were identified by restriction fragment length polymorphisms analysis. These tests could be used for sexing unidentified individuals of wild western and eastern lowland gorillas, and screening contamination of human DNA from non-invasively acquired samples. [ABSTRACT FROM AUTHOR]

Kahuzi-Biega National Park, located in eastern Democratic Republic of Congo, harbours an abundance of endemic species and maintains important populations of Grauer's gorilla (Gorilla gorilla graueri) and elephants (Loxodonta africana). This paper reports on the status of large mammals within the mountain sector of the park in 1996, 2 years after the arrival of half a million Rwandan refugees in the area immediately adjacent to the sector. Large mammal surveys found that gorilla populations had remained stable and that elephants were concentrated within a subsector of the area. However, although chimpanzees (Pan troglodytes), blue monkeys (Cercopithecus mitis), and owl-faced monkeys (C. hamlyni) were abundant and widespread, most terrestrial mammal species were found in very low densities and had been subjected to poaching. Nevertheless, important mammal populations remained and complemented the biodiversity conservation value of the park. [ABSTRACT FROM AUTHOR]

In 1996, the first major biological surveys in the Itombwe Massif in over 30 years revealed that significant areas of natural habitat and remnant faunal populations remain, but that these are subject to ongoing degradation and over-exploitation. At least 10 areas of gorilla Gorilla gorilla graueri occurrence, including eight of 17 areas identified during the first survey of the species in the massif in 1959, were found. Seventy-nine gorilla nest sites were recorded and at least 860 gorillas were estimated to occupy the massif. Fifty-six species of mammals were recorded. Itombwe supports the highest representation, of any area, of bird species endemic to the Albertine Rift highlands. Twenty-two of these species were recorded during the surveys, including the Congo bay owl Phodilus prigoginei, which was previously known from a single specimen collected in Itombwe nearly 50 years ago. No part of Itombwe is officially protected and conservation initiatives are needed urgently. Given the remoteness and continuing political instability of the region, conservation initiatives must collaborate with traditional authorities based in the massif, and should focus at the outset on protecting the gorillas and limiting further degradation of key areas. [ABSTRACT FROM AUTHOR]

We describe the distribution and estimate densities of Grauer's gorillas (Gorilla gorilla graueri) and eastern chimpanzees (Pan troglodytes schweinfurthi) in a 12,770-km2area of lowland forest between the Lowa, Luka, Lugulu, and Oku rivers in eastern Democratic Republic of Congo, the site of the largest continuous population of Grauer's gorillas. The survey included a total of 480 km of transects completed within seven sampling zones in the Kahuzi-Biega National Park lowland sector and adjacent Kasese region and approximately 1100 km of footpath and forest reconnaissance. We estimate total populations of 7670 (4180–10,830) weaned gorillas within the Kahuzi-Biega lowland sector and 3350 (1420–5950) individuals in the Kasese survey areas. Within the same area, we estimate a population of 2600 (1620–4500) chimpanzees. Ape nest site densities are significantly higher within the Kahuzi-Biega lowland sector than in the more remote Kasese survey area in spite of a significantly higher encounter rate of human sign within the lowland sector of the park. Comparison of our data with information obtained by Emlen and Schaller during the first rangewide survey of Grauer's gorillas in 1959 suggests that gorilla populations have remained stable in protected areas but declined in adjacent forest. These findings underscore the key role played by national parks in protecting biological resources in spite of the recent political and economic turmoil in the region. We also show that forest reconnaissance is a reliable and cost-effective method to assess gorilla densities in remote forested areas. [ABSTRACT FROM AUTHOR]

This report updates the distribution and provides abundance estimates for Grauer's gorilla Gorilla gorilla graueri across its 90,000-sq-km range. The authors divide the range of Grauer's gorilla into four regions within which they identify 11 populations and estimate a total of c. 16,900 individuals. Gorillas found in the Kahuzi-Biega lowland–Kasese region represent 86 per cent of the subspecies's total population. Further, approximately 67 per cent of known Grauer's gorillas inhabit Kahuzi-Biega, Maiko and Virunga National Parks. The eastern region of the Democratic Republic of Congo (formerly Zaire) has an extremely high human population growth rate indicating that deforestation and wildlife use trends will continue to increase. Thus, in spite of the encouraging results of surveys to identify populations and characterize abundance, no Grauer's gorilla population should be considered safe from extirpation. [ABSTRACT FROM AUTHOR]

Presents a study on the mitochondrial deoxyribonucleic acid (mtDNA) variability in lowland gorillas (Gorilla gorilla graueri) found at the Kahuzi-Biega National Park in the Democratic Republic of Congo. Details on three species of these gorillas; Sequencing of an internal region of the mtDNA cytochrome oxidase subunit II region; Statistical supporting data.

Focuses on the wild-life expedition in Zaire, organized by the Wildlife Conservation Society (WCS) and the Institut Zairois pour la Conservation de la Nature as part of WCS's Gorilla Conservation Campaign to understand and protect three types of gorillas. Determination of the status, distribution and abundance of the Grauer's gorilla; Development of standardized techniques for surveying gorillas.

Although the vast majority of critically endangered Grauer's gorillas (Gorilla beringei graueri) inhabit low-elevation rain forests, current insights into this ape's life history and ecology stem predominantly from 2 small populations ranging in highland habitats. Here, we provide an initial and non-exhaustive overview of food items of Grauer's gorillas in the Nkuba Conservation Area (NCA), a lower-elevation (500-1,500 m) forest located between Kahuzi-Biega National Park and Maiko National Park in the Democratic Republic of the Congo. Community-based conservation efforts at the NCA aim to protect a population of unhabituated Grauer's gorillas, which we have studied since 2014. Between 2014 and 2020, we simultaneously tracked 1-3 gorilla groups and recorded a total of 10,514 feeding signs on at least 100 plant species, ants, termites, and fungi. Vegetative plant parts (plant stems, leaves, pith, bark, and roots), especially of Marantaceae and Fabaceae, made up close to 90% of recorded feeding signs, with fruit accounting for most of the remainder and a small (<1%) number of feeding signs on invertebrates and fungi. We found that the most frequently recorded food items were consumed year-round, though fruit intake seems to peak in the September-December wet season, possibly reflecting patterns in fruit phenology. The diet of Grauer's gorillas in the NCA differed from that of Grauer's gorillas in highland habitat and instead showed similarities with Grauer's gorillas at the lowland forest of Itebero and with western lowland gorillas (G. gorilla), which live under ecologically comparable conditions., (© 2021 S. Karger AG, Basel.)

Twenty-five specimens of lowland gorilla, including 24 specimens of the western lowland gorilla (Gorilla gorilla gorilla) and 1 specimen of the eastern lowland gorilla (G. gorilla graueri), were investigated by fluorescence in situ hybridization with a human-derived 18S + 28S rDNA probe. Specific hybridization was constitutively seen on the short arms of gorilla acrocentric chromosome pairs 22 and 23, corresponding to human pairs 21 and 22. Only one specimen of western lowland gorilla investigated showed an additional hybridization site at the telomeric short arm of one chromosome 1. From our own results and those in the literature, it is clear that the additional rDNA site on chromosome 1 must be regarded as a rare polymorphism in the subspecies of western lowland gorilla, possibly going back to a founder translocation event. [ABSTRACT FROM AUTHOR]

Summary Many endangered species have experienced severe population declines within the last centuries [ 1, 2 ]. However, despite concerns about negative fitness effects resulting from increased genetic drift and inbreeding, there is a lack of empirical data on genomic changes in conjunction with such declines [ 3–7 ]. Here, we use whole genomes recovered from century-old historical museum specimens to quantify the genomic consequences of small population size in the critically endangered Grauer's and endangered mountain gorillas. We find a reduction of genetic diversity and increase in inbreeding and genetic load in the Grauer's gorilla, which experienced severe population declines in recent decades. In contrast, the small but relatively stable mountain gorilla population has experienced little genomic change during the last century. These results suggest that species histories as well as the rate of demographic change may influence how population declines affect genome diversity. Highlights • Gorilla genomes from museum samples enabled measurement of temporal genomic erosion • Genetic diversity declined and inbreeding increased in Grauer's gorillas • The frequency of deleterious mutations increased significantly in Grauer's gorillas • No temporal changes in genomic parameters were observed in the mountain gorilla Van der Valk et al. investigate the genomic consequences of recent population decline using 100-year-old museum specimens. They find a reduction in genetic diversity, increase in inbreeding, and increase in deleterious mutations in the critically endangered Grauer's gorillas. [ABSTRACT FROM AUTHOR]

In this study, we determined the complete mitochondrial (mt) genome of eastern lowland gorilla,Gorilla beringei grauerifor the first time. The total genome was 16,416 bp in length. It contained a total of 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes and 1 control region (D-loop region). The base composition was A (30.88%), G (13.10%), C (30.89%) and T (25.13%), indicating that the percentage of A+T (56.01%) was higher than G+C (43.99%). Comparisons with the other publicly availableGorillamitogenome showed the conservation of gene order and base compositions but a bunch of nucleotide diversity. This complete mitochondrial genome sequence will provide valuable genetic information for further studies on conservation genetics of eastern lowland gorilla. [ABSTRACT FROM AUTHOR]

Statistics are given regarding Science including the number of survival days of a heart transplant from a pig to a baboon, the percentage of decrease in minutes of coverage of climate news from 2014 to 2015 and the percentage of population of Grauer's gorilla.

The article reports on a survey of largest ape Grauer's gorilla Gorilla beringei graueri in the east of the Democratic Republic of Congo conducted by the Wildlife Conservation Society, Fauna & Flora International Inc. and Institut Congolais pour la Conservation de la Nature from 2011 to 2015.

The article presents the abstract of the paper "Using GIS and Remote Sensing Technologies to Monitor Critical Grauer's Gorilla (Gorilla Gorilla Graueri) Habitat in Eastern Democratic Republic of Congo," by B. Mulley and colleagues to be presented at the 21st Congress of the International Primatological Society, scheduled in Entebbe, Uganda from June 25-30, 2006.

The article presents the abstract of the paper "Landscape-Wide Conservation Status and Distribution of Grauer's Gorilla (Gorilla Beringei Graueri) in Eastern Democratic Republic of Congo (DRC)," by S.C. Nixon and colleagues to be presented at the 21st Congress of the International Primatological Society in Entebbe, Uganda from June 20-25, 2006.

Focuses on the potential increase in the number of endangered Grauer's gorillas in rain forests in Democratic Republic of Congo in 2005. Number of gorillas living in the mountain highlands of Kahuzi-Biega National Park; Population of the gorilla in 1996; Factors that make conservation work dangerous in the Kahuzi-Biega area.

Presents updates on environmental protection worldwide as of June 2004. Population of the endangered eastern lowland gorilla in the Democratic Republic of Congo; Start of the government-approved seal hunt in Canada; Number and size of oxygen-deprived "dead zones" in the world's oceans and seas.