Dear colleagues,

We are happy to share our latest publication in Endangered Species Research:

Heloise J. Pavanato, Gabriel Melo-Santos, Danielle S. Lima, Marcela
Portocarrero-Aya, Mariana Paschoalini, Federico Mosquera, Fernando
Trujillo, Rafael Meneses, Miriam Marmontel, Cláudio Maretti. 2016. Risks of
dam construction for South American river dolphins: a case study of the
Tapajós River. Endangered Species Research 31: 47-60.

ABSTRACT: River dolphins are strongly affected by the construction of
hydroelectric dams. Potential isolation in subpopulations above and below
such dams and the resulting low genetic variability of these subpopulations
can cause extinction at a local level. Here we aimed to estimate density
and population size of South American river dolphins (boto *Inia
geoffrensis* and tucuxi *Sotalia fluviatilis*), map their distribution, and
estimate potential biological removal (PBR) limits in order to evaluate the
effects of population fragmentation between planned dams in the Tapajós
River, Amazonian basin, Brazil. Boat-based surveys were conducted following
a line transect sampling protocol covering different dolphin habitats in 2
stretches of the river divided by rapids. The mark−recapture distance
sampling method was applied to account for animals missed on the trackline.
After the estimation of population sizes by habitat, PBR was calculated.
The farthest upriver sighting of tucuxis was close to the São Luiz do
Tapajós rapids, whereas the farthest upriver sighting of botos was upstream
of the
rapids, suggesting that botos move upstream through the rapids. Estimated
abundance of tucuxis (3372 ind., CV = 0.38) was twice as high as that
estimated for botos (1815 ind., CV = 0.4). The PBR ranged from 11 to 18
ind. for boto and 21 to 34 for tucuxi. Throughout this study, we identified
low abundances of river dolphins compared to other Amazon rivers. Boto may
not be sustainable at a
population level, due primarily to population fragmentation which would
result from the construction of the proposed dams. Precautionary measures
are urgently needed before construction of dams begins in the Tapajós River.

The paper is Open Access and available for download at:

Feel free to contact me for any inquiries at:

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