References of "Petre, Charles-Albert"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailIs western lowland gorilla a good gardener? Effect of fecal matrix and deposition at nest sites on seedling growth
Haurez, Barbara ULg; Brostaux, Yves ULg; Petre, Charles-Albert ULg et al

Conference (2015, June 25)

The Western lowland gorilla is a key dispersal agent, which disperses viable seeds of various size. In consequence of its nesting behavior, gorilla deposits half of its feces, and therefore about half of ... [more ▼]

The Western lowland gorilla is a key dispersal agent, which disperses viable seeds of various size. In consequence of its nesting behavior, gorilla deposits half of its feces, and therefore about half of dispersed seeds, at nest sites. This study was conducted in a logging concession of southeast Gabon where 78 % of the observed nest sites (n=183) were installed in open canopy terra firma forest. The aim of this research was to assess if seed deposition by gorillas (i) in fecal matrix and (ii) at nest sites is advantageous for seedling growth. To assess the effect of fecal matrix, seeds of Santiria trimera (Burseraceae), Chrysophyllum lacourtianum (Sapotaceae) and Plagiostyles africana (Euphorbiaceae) collected in gorilla feces were sown with and without fecal matrix in a nursery at the study site. The impact of seed deposition at nest sites on seedling growth was evaluated in situ. Seedlings of Santiria trimera and Dacryodes normandii (Burseraceae) were installed at nest sites and at closed canopy terra firma forest sites. For both type of trials, seedling growth was monitored. [less ▲]

Detailed reference viewed: 23 (6 ULg)
Full Text
Peer Reviewed
See detailThe role of great apes in seed dispersal of the tropical forest tree species Dacryodes normandii (Burseraceae) in Gabon
Haurez, Barbara ULg; Daïnou, Kasso ULg; Tagg, Nikki et al

in Journal of Tropical Ecology (2015), 31(05), 395-402

The identification of seed dispersers and predators is essential to understand the effect of anthropogenic disturbances, and the associated defaunation process, on tropical forest dynamics in Central ... [more ▼]

The identification of seed dispersers and predators is essential to understand the effect of anthropogenic disturbances, and the associated defaunation process, on tropical forest dynamics in Central Africa. In this study, the animals involved in seed predation and dispersal of Dacryodes normandii (Burseraceae), an endozoochorously dispersed tree species endemic to Gabonese forests, were identified in a site in south-east Gabon using two complementary methods: direct observation and camera-trap monitoring of fruit piles. The combined sampling effort (172 h of direct observations and 796 d of camera trapping) led to the identification of six disperser and eight predator species of D. normandii seeds. With high frequency of consumption (88% and 57% of their visits, respectively) and long visit duration (83 and 23 min, respectively), the western lowland gorilla and central chimpanzee were identified as the main dispersers of this species. Seeds passed through the gorilla gut exhibited high germination success (68%). Rodents were identified as predators of D. normandii seeds, potentially displaying rare secondary dispersal through scatter-hoarding. The results of this study highlight the importance of great apes in the seed dispersal of this tree species. [less ▲]

Detailed reference viewed: 45 (6 ULg)
Full Text
Peer Reviewed
See detailWestern lowland gorilla seed dispersal: Are seeds adapted to long gut retention times?
Petre, Charles-Albert ULg; Tagg, Nikki; Beudels-Jamar, Roseline et al

in Acta Oecologica: International Journal of Ecology (2015)

Detailed reference viewed: 28 (4 ULg)
Full Text
Peer Reviewed
See detailQuantity and spatial distribution of seeds dispersed by a western lowland gorilla population in south-east Cameroon
Petre, Charles-Albert ULg; Tagg, Nikki; Beudels-Jamar et al

in Journal of Tropical Ecology (2015)

Detailed reference viewed: 36 (12 ULg)
Full Text
Peer Reviewed
See detailDifferences in dung beetle activity at western gorilla defecation sites in south-east Cameroon: implications for establishment of Uapaca spp. seedlings
Petre, Charles-Albert ULg; Zinque, Marie-Hélène; Tagg, Nikki et al

in Journal of Tropical Ecology (2015)

Detailed reference viewed: 17 (7 ULg)
Full Text
Peer Reviewed
See detailConservation research presence protects: a case study of great ape abundance in the Dja region, Cameroon
Tagg, Nikki; Willie, Jacob; Duarte, Jesus et al

in Animal Conservation (2015)

Detailed reference viewed: 13 (2 ULg)
Full Text
See detailSeed dispersal by western lowland gorillas: what about gut passage effect?
Haurez, Barbara ULg; Petre, Charles-Albert ULg; Doucet, Jean-Louis ULg

Conference (2014, July 21)

Animal-mediated seed dispersal is an essential ecological process in the tropics. Among African primates, the critically endangered western lowland gorilla (WLG) seems to fulfill many characteristics of ... [more ▼]

Animal-mediated seed dispersal is an essential ecological process in the tropics. Among African primates, the critically endangered western lowland gorilla (WLG) seems to fulfill many characteristics of an effective seed disperser. WLG preferentially disperses species of various seed-size into open canopy habitats suitable for seedling growth. However, few studies have addressed the effects of the passage through the digestive tract on germination. Thus, the effectiveness of WLG in ecological processes governing forest dynamics and regeneration is still poorly known. Seed dispersal by WLG was studied in Central Gabon and Southeast Cameroon. Dispersed seed were identified from fresh fecal samples. Comparative germination trials based on 5 treatments (seeds from fresh fruits, seeds from fresh fruits surrounded by pulp, seeds from fresh fruits with fecal matrix, seeds from feces and seeds from feces with fecal matrix) were realized for 13 species. We recorded germination success for all species and germination delay for 6 species. Our results suggest a neutral gut passage effect for 54% and positive effect for 40% of tested species. Germination success enhancement was linked to another factor than pulp suppression. For two species, pulp suppression enhanced germination success, but not gut passage. The presence of pulp or fecal matrix surrounding the seed seemed to longer germination delay, while gut passage would not fasten germination. Globally, we conclude that WLG dispersed seeds are not damaged by gut passage. Consequently, WLG is thought to provide effective ecological services that could be essential to the maintenance and the recovery of forest ecosystems. [less ▲]

Detailed reference viewed: 34 (5 ULg)
Full Text
See detailWestern lowland gorilla in a logging concession: comparison of density and nesting behavior before and after logging
Haurez, Barbara ULg; Petre, Charles-Albert ULg; Doucet, Jean-Louis ULg

Conference (2014, May 22)

Timber exploitation is rapidly expanding throughout the Congo Basin. In Gabon, timber industry is currently the second working sector and logging concessions cover 45% of the country forest area, largely ... [more ▼]

Timber exploitation is rapidly expanding throughout the Congo Basin. In Gabon, timber industry is currently the second working sector and logging concessions cover 45% of the country forest area, largely overlapping with the range of western lowland gorilla (Gorilla gorilla gorilla WLG). Logging may negatively impact gorilla because of an increase in hunting pressure linked to human concentration and easier access to forest. On the other hand, WLG might benefit from forest opening and the associated growth in Terrestrial Herbaceous Vegetation, following timber felling and roads/trails implementation. In the present study, gorilla density and nesting behavior were studied in a 617,000-ha logging concession located in Central Gabon. A Standing Crop Nest Count census was realized 25 years after the first timber harvesting cycle, consisting in the assessment of the potentiality of logged forest to hold viable WLG populations. A second census was undertaken four to six months after the second logging wave. Comparing nesting behavior and estimated gorilla density between the two census allows to highlight the short-term effects of logging on gorilla populations. A relatively high WLG density was observed during the first census (2.1 weaned gorillas/km²). This figure dropped down to 1.0 weaned gorillas/km² after the second felling cycle. Both density values fall within the range of documented WLG densities documented at other sites. Gorillas consistently nested preferentially in open terra firme forest and built the majority of their nests using herbs of the Marantaceae and Zingiberaceae families. Both these observations underline the importance of Terrestrial Herbaceous Vegetation for nesting. The results of this study suggest that timber exploitation and WLG conservation are not mutually exclusive. The initial high density might traduce an effective anti-poaching strategy for now. The decline in gorilla density observed directly in the second census is probably linked with the avoidance of the disturbance of logging operations. Monitoring the evolution of WLG density would be important in order to control if the figure will rise over time to reach its initial value, but also to assess if a positive effect of Terrestrial Herbaceous Vegetation growth will be observed. [less ▲]

Detailed reference viewed: 45 (6 ULg)
Full Text
Peer Reviewed
See detailProtected Areas in Tropical Africa: Assessing Threats and Conservation Activities
Tranquilli, Sandra; Abedi-Lartey, Michael; Abernethy, Katharine et al

in PLoS ONE (2014)

Detailed reference viewed: 30 (10 ULg)
Full Text
Peer Reviewed
See detailPlant selection for nest building by western lowland gorillas in Cameroon
Willie, Jacob; Tagg, Nikki; Petre, Charles-Albert ULg et al

in Primates : Journal of Primatology (2014)

Detailed reference viewed: 28 (14 ULg)
Full Text
See detailLes concessions forestières peuvent-elles contribuer à la conservation du gorille des plaines de l'Ouest? Exemple d'une concession au Sud-Est du Gabon
Haurez, Barbara ULg; Petre, Charles-Albert ULg; Doucet, Jean-Louis ULg

Poster (2013, November)

Vingt pourcents des forêts du Bassin du Congo sont actuellement principalement affectées à la production de produits ligneux et non-ligneux [FAO-OIBT, 2011]. L'exploitation est un agent de perturbation de ... [more ▼]

Vingt pourcents des forêts du Bassin du Congo sont actuellement principalement affectées à la production de produits ligneux et non-ligneux [FAO-OIBT, 2011]. L'exploitation est un agent de perturbation de ces forêts [WILKIE ET AL., 2000]. Au vu de l’importance économique des industries d’extraction pour les pays de cette région, l’étendue des forêts exploitées pour leur bois ne devrait pas diminuer dans les années à venir, au contraire. La survie de nombreuses espèces animales de forêt dense humide dépend donc de leur capacité à survivre en milieu exploité [JOHNS, 1985]. A ce jour, les concessions forestières jouent potentiellement un rôle crucial pour la protection des différentes espèces de grands singes. En effet, plus de 50% de l'aire de distribution des grands singes d’Afrique de l'Ouest est localisée dans les concessions forestières [MORGAN & SANZ, 2007]. Or, la faune sauvage joue un rôle essentiel pour la durabilité de l'exploitation forestière car elle assure la dissémination des graines [WRIGHT, 2003], dont celles des espèces commerciales. En particulier, le gorille des plaines de l'Ouest (Gorilla gorilla gorilla Savage & Wyman, 1847), espèce en danger critique d'extinction (IUCN), semble jouer un rôle fondamental dans la dispersion des diaspores des espèces ligneuses [ROGERS ET AL., 1998 ; VOYSEY ET AL., 1999]. Cette étude vise à déterminer les interactions entre les gorilles des plaines de l'Ouest et l'exploitation forestière, afin d'évaluer dans quelle mesure ces deux acteurs peuvent être bénéfiques l'un envers l'autre. Plus particulièrement, la densité en gorilles a été estimée dans une zone exploitée 25 ans plus tôt. Le comportement nidificateur des gorilles dans cette zone a été décrit. D'autre part, le rôle potentiel joué par les gorilles dans la dynamique de régénération des forêts exploitées est abordé au travers de l'étude de la dispersion des graines (identification des graines dispersées, contrôle du pouvoir germinatif et détermination de l'impact du passage dans le tractus digestif sur la germination). La densité en gorilles observée au sein du site d'étude est relativement élevée (1,5 gorille/km²). Les gorilles établissent leurs sites de nidification préférentiellement au sein de forêts de terre ferme à canopée ouverte. Ils utilisent fréquemment les anciennes routes d'exploitation, densément couverte de végétation herbacée, pour l'alimentation et la nidification. Au bout de 10 mois de suivi, 45 espèces végétales ont été identifiées comme étant dispersées par les gorilles. Le potentiel germinatif a été évalué pour 36 taxons. Les taux de germination observés dépendent de l'espèce considérée, et varient de 0 à 100%. L'impact du tractus digestif sur la germination a actuellement été testé pour deux espèces, Santiria trimera (Burseraceae) et Chrysophyllum lacourtianum (Sapotaceae). Pour ces deux espèces, les graines passées dans le tractus digestif des gorilles présentent des taux de germination significativement plus élevé que les graines extraites de fruits frais (entourées de pulpe ou non). Les résultats préliminaires de cette étude suggèrent que les forêts exploitées peuvent supporter des densités en gorilles comparables à celles des aires protégées. En outre, via son rôle en tant que disperseur, le gorille pourrait avoir un rôle crucial dans la régénération des forêts post-exploitation. L'exploitation forestière et la conservation des gorilles des plaines de l'Ouest paraissent donc compatibles. [less ▲]

Detailed reference viewed: 66 (22 ULg)
Full Text
Peer Reviewed
See detailImpacts of WLG on the regeneration of logged forests: preliminary insights in a Gabonese logging concession
Haurez, Barbara ULg; Petre, Charles-Albert ULg; Doucet, Jean-Louis ULg

in Folia Primatologica : International Journal of Primatology = Internationale Zeitschrift für Primatologie = Journal international de Primatologie (2013, September), 84(3-5), 284-285

Detailed reference viewed: 50 (28 ULg)