Predator density and timing of arrival affect reef fish community assembly

Most empirical studies of predation use simple experimental approaches to quantify the effects of predators on prey (e.g., using constant densities of predators, such as ambient vs. zero). However, predator densities vary in time, and these effects may not be well represented by studies that use con...

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Bibliographic Details
Published in:Ecology (Durham) 2013-05, Vol.94 (5), p.1057-1068
Main Authors: Stier, Adrian C., Geange, Shane W., Hanson, Kate M., Bolker, Benjamin M.
Format: Article
Language:English
Subjects:
Agnatha. Pisces
Animal and plant ecology
Animal, plant and microbial ecology
Animals
Biodiversity
Biological and medical sciences
carnivores
Communities
community development
community structure
Coral Reefs
diversity
Ecological competition
Ecology
field experimentation
Fish
fish communities
Fishes - classification
Fundamental and applied biological sciences. Psychology
General aspects
Moorea, French Polynesia
Paracirrhites
Paracirrhites arcatus
Predation
Predators
Predatory Behavior - physiology
priority effects
reef fish
Species
Species diversity
Statistical variance
Synecology
temporal variation
Time Factors
variance
Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution
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Summary:Most empirical studies of predation use simple experimental approaches to quantify the effects of predators on prey (e.g., using constant densities of predators, such as ambient vs. zero). However, predator densities vary in time, and these effects may not be well represented by studies that use constant predator densities. Although studies have independently examined the importance of predator density, temporal variability, and timing of arrival (i.e., early or late relative to prey), the relative contribution of these different predator regimes on prey abundance, diversity, and composition remains poorly understood. The hawkfish ( Paracirrhites arcatus ), a carnivorous coral reef fish, exhibits substantial variability in patch occupancy, density, and timing of arrival to natural reefs. Our field experiments demonstrated that effects of hawkfish on prey abundance depended on both hawkfish density and the timing of their arrival, but not on variability in hawkfish density. Relative to treatments without hawkfish, hawkfish presence reduced prey abundance by 50%. This effect increased with a doubling of hawkfish density (an additional 33% reduction), and when hawkfish arrived later during community development (a 34% reduction). Hawkfish did not affect within-patch diversity (species richness), but they increased between-patch diversity (beta) based on species incidence (22%), and caused shifts in species composition. Our results suggest that the timing of predator arrival can be as important as predator density in modifying prey abundance and community composition.
ISSN:0012-9658
1939-9170
DOI:10.1890/11-1983.1