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The effect of structural complexity, prey density, and "predator-free space" on prey survivorship at created oyster reef mesocosms

January 1, 2011

Interactions between predators and their prey are influenced by the habitat they occupy. Using created oyster (Crassostrea virginica) reef mesocosms, we conducted a series of laboratory experiments that created structure and manipulated complexity as well as prey density and “predator-free space” to examine the relationship between structural complexity and prey survivorship. Specifically, volume and spatial arrangement of oysters as well as prey density were manipulated, and the survivorship of prey (grass shrimp, Palaemonetes pugio) in the presence of a predator (wild red drum, Sciaenops ocellatus) was quantified. We found that the presence of structure increased prey survivorship, and that increasing complexity of this structure further increased survivorship, but only to a point. This agrees with the theory that structural complexity may influence predator-prey dynamics, but that a threshold exists with diminishing returns. These results held true even when prey density was scaled to structural complexity, or the amount of “predator-free space” was manipulated within our created reef mesocosms. The presence of structure and its complexity (oyster shell volume) were more important in facilitating prey survivorship than perceived refugia or density-dependent prey effects. A more accurate indicator of refugia might require “predator-free space” measures that also account for the available area within the structure itself (i.e., volume) and not just on the surface of a structure. Creating experiments that better mimic natural conditions and test a wider range of “predator-free space” are suggested to better understand the role of structural complexity in oyster reefs and other complex habitats.

Citation Information

Publication Year 2011
Title The effect of structural complexity, prey density, and "predator-free space" on prey survivorship at created oyster reef mesocosms
DOI 10.1371/journal.pone.0028339
Authors Austin T. Humphries, Megan La Peyre, Gary A. Decossas
Publication Type Article
Publication Subtype Journal Article
Series Title PLoS ONE
Series Number
Index ID 70032512
Record Source USGS Publications Warehouse
USGS Organization Coop Res Unit Atlanta

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