Home range and movements of Amazon river dolphins Inia geoffrensis in the Amazon and Orinoco river basins

Authors

Mosquera-Guerra, F.

Additional Authors

Trujillo, F.; Oliveira-da-Costa, M.; Marmontel, M.; Van Damme, P.A.; Franco, N.; Córdova, L.; Campbell, E.; Alfaro-Shigueto, J.; Mena, J.L.; Mangel, J.C.; Usma Oviedo, J.S.; Carvajal-Castro, J.D.; Mantilla-Meluk, H.; Armenteras-Pascual, D.

Year

2021

Volume & Issue

Vol. 45

Pages

269–282

Country / Region

South America, Brazil, Colombia, Latin America, Bolivia, Peru

Document Type

Peer-reviewed journal article

Species

Amazon river dolphin, Tucuxi

Science Keywords

Range decline, Abundance, Habitat Use

Conservation Measure

Regional collaboration, Protected Areas, Research and monitoring

Threat Keywords

All threats reviewed

Abstract

Studying the variables that describe the spatial ecology of threatened species allows us to identify and prioritize areas that are critical for species conservation. To estimate the home range and core area of the Endangered (EN) Amazon river dolphin Inia geoffrensis, 23 individuals (6f, 17m) were tagged during the rising water period in the Amazon and Orinoco river basins
between 2017 and 2018. The satellite tracking period ranged from 24 to 336 d (mean ± SE = 107 ± 15.7 d), and river dolphin movements ranged from 7.5 to 298 km (58 ± 13.4 km). Kernel density estimates were used to determine minimum home ranges at 95% (K95 = 6.2 to 233.9 km2; mean = 59 ± 13.5 km2) and core areas at 50% (K50 = 0.6 to 54.9 km2; mean = 9 ± 2.6 km2). Protected areas accounted for 45% of the K50 estimated core area. We observed dolphin individuals crossing country borders between Colombia and Peru in the Amazon basin, and between Colombia and Venezuela in the Orinoco basin. Satellite tracking allowed us to determine the different uses of riverine habitat types: main rivers (channels and bays, 52% of recorded locations), confluences (32%), lagoons (9.6%), and tributaries (6.2%). Satellite monitoring allowed us to better understand the ecological preferences of the species and demonstrated the importance of maintaining aquatic landscape heterogeneity and spatial connectivity for effective river dolphin conservation.

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