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Consequences of the size structure of fish populations for their effects on a generalist avian predator
- Source :
- Oecologia
- Publisher :
- Springer Nature
-
Abstract
- Size-structured interspecific interactions can shift between predation and competition, depending on ontogenetic changes in size relationships. I examined the effects of common carp (Cyprinus carpio), an omnivorous fish, on the reproductive success of the red-necked grebe (Podiceps grisegena), an avian gape-limited predator, along a fish size gradient created by stocking distinct age-cohorts in seminatural ponds. Young-of-the-year (0+) carp were an essential food source for young grebes. Only adult birds were able to consume 1-year-old (1+) fish, while 2-year-old (2+) fish attained a size refuge from grebes. Amphibian larvae were the principal alternative prey to fish, followed by macroinvertebrates, but the abundance of both dramatically decreased along the carp size gradient. Fledging success was 2.8 times greater in ponds with 0+ versus 1+ carp; in ponds with 1+ carp, chicks received on average 2.6–3 times less prey biomass from their parents, and over 1/3 of broods suffered total failure. Breeding birds avoided settling on 2+ ponds. These results show that changes in prey fish size structure can account for shifts from positive trophic effects on the avian predator to a negative impact on the predator’s alternative resources. However, competition did not fully explain the decrease in grebe food resources in the presence of large fish, as carp and grebes overlapped little in diet. In experimental cages, 1+ carp totally eliminated young larvae of amphibians palatable to fish. In field conditions, breeding adults of palatable taxa avoided ponds with 1+ and older carp. Non-trophic interactions such as habitat selection by amphibians or macroinvertebrates to avoid large fish may provide an indirect mechanism strengthening the adverse bottom-up effects of fish on birds. Electronic supplementary material The online version of this article (doi:10.1007/s00442-010-1862-3) contains supplementary material, which is available to authorized users.
- Subjects :
- Avian clutch size
Carps
Community ecology - Original Paper
Population Dynamics
Common carp
Predation
Amphibians
Birds
Animals
Body Size
Carp
Predator–prey dynamics
Trait-mediated effects
Ecosystem
Ecology, Evolution, Behavior and Systematics
Grebe
Population Density
biology
Competition
Ecology
Reproduction
fungi
Pond community
Interspecific competition
Feeding Behavior
biology.organism_classification
Clutch Size
Larva
Predatory Behavior
Forage fish
Podiceps grisegena
sense organs
Subjects
Details
- Language :
- English
- ISSN :
- 00298549
- Volume :
- 166
- Issue :
- 2
- Database :
- OpenAIRE
- Journal :
- Oecologia
- Accession number :
- edsair.doi.dedup.....246c85d73bdec951eb7f992301007187
- Full Text :
- https://doi.org/10.1007/s00442-010-1862-3