Plant-animal mutualistic interaction: the case of the Uapaca trees and the western lowland gorilla (G. g. gorilla)

in Primate Tidings (2012), 27

Logging concession as semi-protected areas for gorillas'conservation? A case study in central Gabon

Conference (2012, October 04)

Interactions between western lowland gorillas (Gorilla gorilla gorilla Savage & Wyman 1847) and timber exploitation: Preliminary insights in a Gabonese logging concession

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 ▲]

Role of western lowland gorilla (Gorilla gorilla gorilla Savage & Wyman, 1847) on the dynamics of tropical logged forest ecosystems

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 ▲]