Effects of Dipteryx oleifera fruiting on space use by the Central-American agouti: consequences for seed dispersal
11 / 2008 - unknown
Project description This study concerns space use of the Central-American agouti Dasyprocta punctata, a medium-sized diurnal rodent, and consequences for seed dispersal of the emergent tree Dipteryx oleifera in the tropical forest of Barro Colorado Island (BCI), Panama. Besides seed predation, rodents also scatter-hoard seeds as food supplies. Controversy exists whether rodents are effective seed dispersers. One of the questions is whether rodents might disperse seeds over longer distances. A possible mechanism for long distance seed dispersal is through feeding excursions by rodents to temporary resource patches, thereby expanding their usual homerange. This theory will be tested for agoutis feeding on Dipteryx seeds. Dipteryx fruits on BCI in the dry period (January-March) when food availability is scarce. Agoutis seem to travel long distances to feed on fruits of Dipteryx and have been observed in large number near these trees. We hypothesize that fruiting of Dipteryx effects space use of agoutis, and that this relation is inversely related to Dipteryx-density within agouti home ranges. Furthermore, we hypothesize that seeds are dispersed over larger distances if agoutis make feeding excursions, because agoutis tend to cache seeds in their high use areas, which are mostly located in the centre of their home range. We expect that a causal relation exists between Dipteryx-density and distance of seed dispersal. Spatial ecology of agoutis will be investigated by radio-tracking 10-15 agoutis in the tropical forest of BCI. This will be related to seed dispersal by tracking individual seeds using radio-transmitters and conventional seed-tracking methods.
Other information This thesis is part of the research project of Dr. P.A. Jansen Tropical tree seed dispersal in a multi-trophic context. An automated radio telemetry study at Barro Colorado Island , Panama