The Bolivian river dolphin, known locally as the bufeo, is one of 4 species of river dolphin in South America. Endemic to the upper basin of the Madeira in the Bolivian Amazon region, the species is categorized as Endangered on the IUCN Red List. This article provides information related to the geographic distribution of the species, and a review of the studies of its abundance that have been conducted in Bolivia since the 1970s. We discuss the surveys, the analysis methods used in the different studies, and the ways in which these methods might influence the population estimates. We found 63 population abundance estimates for the Bolivian river dolphin across 17 reviewed publications. These studies report relative abundance data for rivers that range from 0.2 to 2.81 bufeos km^-1, and density ranges from 0 to 7.59 bufeos km^-2. The information presented here reflects the knowledge of the population size of the species in Bolivia obtained over 4 decades, and will be useful for developing conservation strategies and as a tool for decision makers.

The taxonomy of the South American river dolphins of the genus Inia has been a focus of intense debate. While traditionally it is thought to be composed of a single species with three geographically structured subspecies (Inia geoffrensis geoffrensis, I. g. humboldtiana, and I. g. boliviensis), recent molecular studies have highlighted substantial differentiation, suggesting the existence of two species (I. geoffrensis and I. araguaiaensis). Despite this evidence, the recognition of the specific status of these taxa has been hindered by inconsistent morphological diagnoses. Here, we aim to provide evidence for the morphological differentiation (or lack thereof) between subspecies and putative species. We employ geometrics and traditional morphometrics to measure skull variation to support efforts of integrative taxonomy. Our results show that morphometric diversity within the group is inconsistent with a single taxon. Morphometric evidence supports the traditional differentiation of three distinct morphotypes within the analyzed sample. These morphotypes largely correspond to described subspecies I. g. geoffrensis, I. g. humboldtiana—the latter differing from the former by size—and I. g. boliviensis, which differs from the remaining groups by shape. Furthermore, morphometric data show no differences between I. g. geoffrensis and a newly proposed species, I. araguaiaensis. Given the conservation importance of this genus and the different threats they are subject to, we strongly suggest an urgent integrative taxonomic treatment of the group to better protect these singular cetaceans.

Update on the freshwater distribution of Sotalia in Colombia, Ecuador, Peru, Venezuela and Suriname

Animal-plant interactions in Neotropical forests are complex processes. Within these processes, mid- to large-sized mammals consume fruits and seeds from several species; however, because of their size these mammals are overhunted, resulting in defaunated forests. Our objective was to evaluate and compare seed removal and survivorship in a forest with no hunting, a forest with moderate or reduced hunting, and a forest with higher hunting pressure. We examined the interaction between Astrocaryum gratum and white lipped peccary (Tayassu pecari) to tease apart the defaunation process. To isolate and evaluate mammal seed removal rates and to identify the causes of mortality on A.gratum, under the three different hunting pressures forests, we used exclosures in each one. In four different forest-patches for each forest, we positioned a block-treatment consisting of three exclosures (total exclusion, peccary exclusion, and control), randomly distributed 5m apart and the block-treatments spaced 50-75m apart from one another. We established 15 treatments in total for each patch (5 blocks per patch). There were 20 blocks within each forest type. For total exclusion, all vertebrates were excluded using galvanized wire mesh exclosures. The second, the peccary exclusion, was designed to stop peccaries from entering treatment units, providing access only to small vertebrates; larger mammals were able to access the treatment unit by reaching over the sides and the open top; finally, the Control allowed full access for all mammals. Fresh A. gratum fruits were collected from the forest floor under different adult trees throughout the study area. In each exclosure treatment, twenty A.gratum seeds were placed, and their removal was recorded. In total, 3 600 seeds were analyzed. Seed survival was lower in unhunted forest compared to areas with moderate hunting and forest with a higher hunt pressure, supporting the hypothesis of the importance of mammals in seed removal. From the initial 400 seeds left for each control exclosure in each type of forest, there was a significant difference between the seed removal; 1.75% seeds in the unhunted forest remained; 43.5% in the moderately hunted forest, and 48.5% in hunted forest. The main cause of seed mortality was white lipped peccaries; while in the forests without them, the main removal was caused by rodents and a higher insect infection was observed in the heavily hunted forest. Our results indicated that defaunation affects seed survivorship.