Dear friends,
We hope this finds you well. We wanted to share with the ListServ our
new publication:
Pivari, D.; Pagliani, B.; Lemos, L.; Lima, D. & Gravena, W. 2021.
Monitoring a critical population of the Bolivian river dolphin, Inia
boliviensis, before and after closing the floodgates of a hydroelectric
dam in the Amazon Basin, Brazil: A quantitative Analysis. Journal for
Nature Conservation: https://doi.org/10.1016/j.jnc.2021.126082
<https://doi.org/10.1016/j.jnc.2021.126082>
Cheers!
Abstract:
Dam constructions
<https://www.sciencedirect.com/topics/earth-and-planetary-sciences/dam-construction> threaten
aquatic fauna, degrading their habitats and causing population
fragmentation. Environmental impact studies
<https://www.sciencedirect.com/topics/earth-and-planetary-sciences/environmental-impact-study> were
carried out from March 2010 to July 2015 as part of the licensing
process concerning the Jirau Hydroelectric Dam construction, located on
the Madeira River, Rondônia, Brazil, aiming to assess its impacts on the
local fauna. The dam closed its gates in December 2012 and the water
level rose from 2013 to 2015, creating a 468 km2 reservoir. Dams may be
a source of negative effects to several species, including the Bolivian
river dolphin, /Inia
<https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/inia> boliviensis/,
which have a restricted distribution in northern Bolivian rivers and
part of the Madeira River Basin. This study evaluated the presence of
/I. boliviensis/ in different sections of the Madeira River before
reservoir filling (BRF) and after reservoir filling (ARF) through a
quantitative analysis. Dolphins were actively searched along linear
transects in four sections of the river: Abunã, Mutum, Caiçara and
Canteiro, over 125 km (250 km round trip). A total effort of 986 h was
carried out along 210 days during the hydrological seasons (falling,
low, rising and high-water level). Twenty-nine (29) groups were recorded
BRF in the direct dam influence area (N = 62), while thirty-eight (38)
groups were documented ARF (N = 111). The highest number of sightings
was recorded in Abunã during both periods: 24 in BRF (N = 50) and 33 in
ARF (N = 101). The greatest number of dolphins was detected during the
falling and low hydrological seasons: 19 in BRF (N = 48) and 30 in ARF
(N = 92). This is expected, since decreasing water levels lead to a
higher concentration of prey and, consequently, higher numbers of
dolphins can be observed. Standardized methodology and experienced staff
are essential to ensure adequate dolphin population estimates,
especially in these critical habitats, where the main impacts caused by
the dam are population fragmentation, isolation and extirpation, and
reproductive segregation.
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