Ecologically driven differences in individual diet specialization across three populations of Guiana dolphin

Populations usually considered foraging generalists may include specialized individuals that feed on a restricted subset of the prey spectrum consumed by the population. By analyzing the time series of δ 13 C and δ 15 N values in sequential growth layer groups within tooth dentin, we measured popula...

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Bibliographic Details
Published in:Oecologia 2023-02, Vol.201 (2), p.397-408
Main Authors: Teixeira, Clarissa R., Botta, Silvina, Cremer, Marta J., Marcondes, Milton C. C., Pereira, Luiza B., Newsome, Seth D., Jorge, Fábio G. Daura, Simões-Lopes, Paulo C.
Format: Article
Language:English
Subjects:
Analysis
Animals
Aquatic mammals
Biomedical and Life Sciences
Coexistence
Delphinidae
Diet
Dolphins
Dolphins & porpoises
Ecology
Ecosystem
Environmental conditions
Foraging
Foraging behavior
Geographical distribution
Hydrology/Water Resources
Latitudinal variations
Life Sciences
Marine mammals
Plant Sciences
Population Ecology–Original Research
Populations
Prey
Resource availability
Rivers
Social aspects
Social organization
Teeth
Time Factors
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Summary:Populations usually considered foraging generalists may include specialized individuals that feed on a restricted subset of the prey spectrum consumed by the population. By analyzing the time series of δ 13 C and δ 15 N values in sequential growth layer groups within tooth dentin, we measured population- and individual-level variation in resource use of three populations of Guiana dolphins ( Sotalia guianensis )—Caravelas River, Babitonga Bay, and Norte Bay—along a latitudinal gradient in the southwestern Atlantic Ocean. We show that the Guiana dolphin at Caravelas River is a generalist population consisting of individual dietary specialists, likely due to the absence of other resident dolphin populations thus allowing individuals to target prey across a wide range of habitats. The Babitonga Bay population is also composed of individual specialists potentially due to the selective foraging behavior of some individuals on high-quality prey sources within and near the bay. In contrast, the Norte Bay population comprises individual generalists, which likely reflects its distinctive cohesive social organization, coexistence with two other dolphin species, and an opportunistic foraging strategy in response to resource fluctuations inherent to the southern limit of the species distribution. Although the Guiana dolphin is generally considered to be a dietary generalist at the population level, our findings reveal that the total niche width of populations and the degree of individual diet specialization are highly context dependent, suggesting dietary plasticity that may be related to a latitudinal gradient in resource availability and environmental conditions. Graphical abstract
ISSN:0029-8549
1432-1939
DOI:10.1007/s00442-022-05312-7