References of "Haurez, Barbara"
     in
Bookmark and Share    
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: 42 (20 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: 42 (24 ULg)
Full Text
Peer Reviewed
See detailImpacts of logging and hunting on western lowland gorilla (Gorilla gorilla gorilla) populations and consequences for forest regeneration. A review
Haurez, Barbara ULg; Petre, Charles-Albert ULg; Doucet, Jean-Louis ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2013), 17(2), 364-317

Timber exploitation is rapidly expanding throughout the Congo Basin. Forest areas assigned to timber harvesting have sharply expanded over the decades and logging concessions now largely overlap with the ... [more ▼]

Timber exploitation is rapidly expanding throughout the Congo Basin. Forest areas assigned to timber harvesting have sharply expanded over the decades and logging concessions now largely overlap with the range of western lowland gorilla (Gorilla gorilla gorilla Savage & Wyman, 1847). However this species, which is considered as critically endangered by IUCN, could play an essential role in maintaining the structure and composition of tropical rainforest notably through seed dispersal services. This is likely due to its frugivorous diet, high stomach capacity and ability to swallow seeds of variable sizes. Moreover gorillas have a long gut retention time of ingested food, travel long daily distances and deposit most ingested seeds in suitable habitats for plant development (such as logging gaps). Consequently, the preservation of the role of gorilla in forest regeneration is essential in the context of logged forest ecosystems. Timber harvesting has two major opposing impacts on gorilla populations: on the one hand, gorillas benefit from growth of herbaceous vegetation (e.g. Marantaceae and Zingiberaceae) following forest canopy opening, as such herbs provide both staple food and nest-building materials; on the other hand, gorilla populations suffer with the rise in hunting associated with logging activity, especially with road network installation. Considering the potential negative knock-on effects of logging concessions on the ecological function of western lowland gorilla, the implementation of timber harvesting methods that preserve gorilla populations is a considerable challenge for forest sustainability, as well as for gorilla’s conservation. [less ▲]

Detailed reference viewed: 39 (19 ULg)
Full Text
See detailWestern lowland gorilla populations and logging concessions: is the coexistence possible?
Haurez, Barbara ULg; Petre, Charles-Albert ULg; Doucet, Jean-Louis ULg

Conference (2013, April)

Timber exploitation is rapidly expanding throughout the Congo Basin. Around 26 % of the moist forests are devoted to logging activities. Logging concessions largely overlap with the range of western ... [more ▼]

Timber exploitation is rapidly expanding throughout the Congo Basin. Around 26 % of the moist forests are devoted to logging activities. Logging concessions largely overlap with the range of western lowland gorilla (WLG) considered as critically endangered by IUCN. However, this species could play an essential role in maintaining vegetal diversity notably through seed dispersal services. Particularly some tree species harvested for their timber may be dispersed by WLG. In this communication interactions between WLG and a timber exploitation are studied in Central Gabon. WLG density is estimated in an Annual Allowable Cut (AAC), and nesting behavior is described. Seeds dispersed by WLG are identified through fecal analysis and germination trials are conducted to assess seed viability after gut passage. Four treatments are realized for the most abundant species: passed seeds, passed seeds in fecal matrix, seeds surrounded by fresh pulp and seeds extracted from fresh fruits. A relatively high WLG density is observed in the AAC (2.0 weaned gorillas/km²). WLG nest preferentially in open terra firme forest and frequently use old logging road covered with herbaceous vegetation for nesting and feeding. They avoid nesting in closed terra firme forest. Seed dispersal and impacts of the passage in gorilla’s gut on seed germination are currently described. Germination success after gut passage depends on the seed species and varies from 0.0 to 100% in the course of monitoring time. The first results of this study suggest that timber exploitation and WLG conservation are not mutually exclusive. WLG are important agents of forest regeneration by dispersing seeds in logged areas. Nest sites in logging gaps could be particularly favorable for seedlings development. This consideration must encourage forest managers to strengthen WLG-conservative practices in their concessions. [less ▲]

Detailed reference viewed: 41 (6 ULg)
Full Text
Peer Reviewed
See detailThe Enhancement of Secondary Succession by Western Lowland Gorillas (Gorilla gorilla gorilla) in a Moist Tropical Forest of Southeast Cameroon
Petre, Charles-Albert ULg; Haurez, Barbara ULg; Tagg, Nikki et al

in Folia Primatologica : International Journal of Primatology = Internationale Zeitschrift für Primatologie = Journal international de Primatologie (2013), 84

Detailed reference viewed: 11 (5 ULg)
Full Text
Peer Reviewed
See detailRole of the western lowland gorilla (Gorilla gorilla gorilla) in seed dispersal in tropical forests and implications of its decline
Petre, Charles-Albert ULg; Tagg, Nikki; Haurez, Barbara ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2013), 17(3), 517-526

Detailed reference viewed: 47 (7 ULg)
Full Text
See detailPlant-animal mutualistic interaction: the case of the Uapaca trees and the western lowland gorilla (G. g. gorilla)
Petre, Charles-Albert ULg; Tagg, Nikki; Beudels-Jamar, Roseline et al

in Primate Tidings (2012), 27

Detailed reference viewed: 24 (10 ULg)
See detailInteractions between western lowland gorillas (Gorilla gorilla gorilla Savage & Wyman 1847) and timber exploitation: Preliminary insights in a Gabonese logging concession
Haurez, Barbara ULg; Petre, Charles-Albert ULg; Doucet, Jean-Louis ULg

Poster (2012, August 15)

Interactions between western lowland gorillas (WLG) and a timber exploitation were studied in Central Gabon. WLG densities were estimated in two sites with different logging histories (not logged vs ... [more ▼]

Interactions between western lowland gorillas (WLG) and a timber exploitation were studied in Central Gabon. WLG densities were estimated in two sites with different logging histories (not logged vs. logged one month before), and nesting behavior was described. Seeds dispersed by WLG were identified through fecal analysis and germination trials assessed seed viability after gut passage. Four treatments were realized for the most abundant species: passed seeds, passed seeds in fecal matrix, seeds surrounded by fresh pulp and seeds extracted from fresh fruits. Relatively high WLG densities were observed in the concession (3.7 weaned gorillas/km² in unlogged forest and 1.7 weaned gorillas/km² in logged forest). WLG nested preferentially in open areas (particularly open terra firme and swamp forest) and frequently used old logging road network for nesting and feeding. WLG dispersed sixteen species during the course of the study (February-May 2011). The most dispersed species was Santiria trimera (Burseraceae). The germination successes of S. trimera were significantly higher after gut passage (N=378; P<0.001) because of pulp removal and seed coat scarification. This pilot study suggests that timber exploitation and WLG conservation are not mutually exclusive. WLG are important agents of forest regeneration by dispersing seeds in logged areas. Nest sites in logging gaps could be particularly favorable for seedlings development. This consideration must encourage forest managers to strengthen WLG-conservative practices in their concessions. [less ▲]

Detailed reference viewed: 48 (15 ULg)
See detailRole of western lowland gorilla (Gorilla gorilla gorilla Savage & Wyman, 1847) on the dynamics of tropical logged forest ecosystems
Haurez, Barbara ULg; Petre, Charles-Albert ULg; Doucet, Jean-Louis ULg

Poster (2012, February 08)

The western lowland gorilla (Gorilla gorilla gorilla Savage & Wyman) (WLG) which is considered as a critically endangered species by IUCN, could play a fundamental function in seeds dispersal of several ... [more ▼]

The western lowland gorilla (Gorilla gorilla gorilla Savage & Wyman) (WLG) which is considered as a critically endangered species by IUCN, could play a fundamental function in seeds dispersal of several plant species. This could be related to its frugivorous diet, its stomach capacity and the long gut retention time of the ingested food, its extensive daily path length, and its ability to swallow seeds of variable sizes. In addition, this animal tends to deposit most of ingested seeds in suitable habitats (especially logging gaps and old logging roads) for light-demanding plant development. This research will be conducted within the moist evergreen forest of Central Gabon in a logging concession granted to the company CEB Precious Woods. A preliminary study was undertaken as a Master thesis. It was aiming at obtaining a first insight of interactions between WLG and timber exploitation in Central Gabon and at assessing the extent to which they may benefit of each other. WLG abundances were estimated in unlogged and logged sites in the concession, and nesting behavior described. Seeds dispersed during the study period (February-May) by WLG were identified through fecal analysis. Relatively high WLG abundances were observed in the concession. WLG were found to nest preferentially in open areas and to frequently use old logging road network for nesting and feeding. Sixteen species were observed to be dispersed by WLG. Seeds of the most abundant species, Santiria trimera, were subjected to four treatments: (1) passed seeds, (2) passed seeds in fecal matrix, (3) seeds surrounded by fresh pulp and (3) seeds extracted from fresh fruits. The germination successes of S. trimera were significantly higher after gut passage partly thanks to fruit pulp removal. Our PhD study aims to characterize the functional ecology of WLG in tropical forests dynamics, especially regarding logging biotopes. Our research will be organized in three parts: (1) the survey of gorilla populations in the study area coupled with the characterization of their nests and habitats, (2) the study of dispersed species and of the effect of passage through gorilla gut on seed germination, (3) the estimate of dispersal distances for the species Santiria trimera (Burseraceae) by using molecular markers. Data for the second and third parts will be collected in one site selected thanks to the results of the survey for its high gorilla density, to assess the following assumptions: (1) gorillas favor the regeneration of many plant species, including timber trees; (2) they improve the genetic diversity and limit the genetic structure by widening the genetic pool and dispersing diasporas on large distances. If these hypotheses are accepted, sylvicultural practices may be adapted so as to take advantage from the presence of gorilla population. [less ▲]

Detailed reference viewed: 73 (6 ULg)
See detailInteractions entre les gorilles des plaines de l'Ouest et l'exploitation forestière : Implications sylvicoles pour une forêt du Centre du Gabon
Haurez, Barbara ULg

Master's dissertation (2011)

The aim of this master thesis is to study the interactions between western lowland gorillas (Gorilla gorilla gorilla Savage & Wyman) and timber exploitation in a forest of Central Gabon. The research work ... [more ▼]

The aim of this master thesis is to study the interactions between western lowland gorillas (Gorilla gorilla gorilla Savage & Wyman) and timber exploitation in a forest of Central Gabon. The research work has been organized around tree main axis: (i) The determination of the impact of timber exploitation on gorilla density. Gorillas’ densities have been estimated in unlogged forest and in logged forest by pedestrian inventories of nesting sites. They are respectively equal to 3.7 and 1.7 weaned gorillas per km². Nevertheless these values are based upon small size samplings and it is not possible to assess if the difference between them is significant. (ii) The characterization of nesting habitat. We brought to light gorillas’ preference for relatively open sites for nesting. Particularly swamps and open terra firme forest are appreciated by gorillas for the construction of the nests. The vegetation type in which the nesting site is located has an influence on the structure and the composition of the nest. Plants of the Marantaceae and Zingiberaceae families are the most frequently used for nest construction. Moreover, we noticed the use of the old road logging network for nesting and feeding. (iii)The determination of the effect of endozoochory on seeds germination. The effect of endozoochory depends upon the botanical species of the seed. Too few results have been obtained in order to allow a reliable comparison of germination rates between ingested seeds and seeds extracted from fruits. However, the germination rate of the species Santiria trimera (Oliv.) Aubrév. (Burseraceae) seems to be enhanced by endozoochory, in particular by the removal of the pulp surrounding the seeds. This study demonstrates that western lowland gorilla is a species that adapts relatively well to timber exploitation. Besides thanks to its highly frugivorous diet and its nesting behavior, the gorilla is an effective seeds disperser. The role of the gorilla in forest regeneration seems to be inconsiderable. Complementary studies, particularly a long term study, would be necessary in order to examine thoroughly into the conclusions brought by this work. [less ▲]

Detailed reference viewed: 90 (17 ULg)