Is western lowland gorilla a good gardener? Effect of fecal matrix and deposition at nest sites on seedling growth

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.