| dc.description.abstract | The Amazon Basin and its floodplains are a highly productive ecosystem that habitats many of the world’s freshwater species. The flood pulse which seasonally inundates the flooded forests creates dynamic environments with varied degrees of adaptations within fauna species. River dolphins in the Amazon are facing different threats, although their abundance and encounter rates seem to be at a high level still. There is a large difference in preferences for distribution between Inia geoffrensis and Sotalia fluviatilis, where encounter rates of I. geoffrensis is higher than S. fluviatilis, but group sizes show an opposite distribution. The environmental variable confluence has a high effect on the encounter rates of both dolphin species, where the presence of this habitat on a transect line, leads to an increase in encounter rates. The anthropogenic variables tested for this thesis showed little effect on encounter rates, although the distance from a community showed a negative effect on encounter rates on I. geoffrensis, and motor traffic had a positive effect on S. fluviatilis. The psychological traits of these river dolphins show that the riverine habitat preference of these species is also different, where Inia prefer habitat along the river margins, and Sotalia prefers to be in the center of the river. | |
