Master theses

Tropical forest gaps have a distinct vegetation structure and microclimate than the surrounding forest. When these differences affect the behaviour of seed dispersing animals, population maintenance of trees which depend on those animals can be affected.

In a field experiment in the Bolivian part of the Amazon, the effect of habitat on seed dispersal of the tropical tree Bertholletia excelsa mediated by Dasyprocta spp., a large scatterhoarding rodent, was studied.

Dispersal distances of seeds deposited in gaps without vegetation were compared with those from undisturbed forest. Seeds from gaps had a shorter dispersal distance than seeds from the forest. Differences of the distribution of those distances between the two habitats could not be detected.

Also the effect of a gap on dispersal direction was studied by depositing seeds at the edge of a gap and monitoring the dispersal. A gap did neither attract nor repel the agouti for cashing seeds because there were as many seeds deposited in the gaps as predicted by the cashing pattern of seeds in undisturbed forest sites.