The Effect of Structural Complexity, Prey Density, and “Predator-Free Space” on Prey Survivorship at Created Oyster Reef Mesocosms

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

Production-Consumption Relationships of Edible Fats and Proteins from Animals and Oilseeds

Excerpt from the Introduction: The information in this paper was developed as a part of a study to determine the influence of world fat and oil consumption on protein supply. The paper concerns past, present, and future world and U.S. production of edible fats and oils as they influence edible protein supplies from commodities that yield both types of products. The production and values of fat and oil and protein from various oilseeds, red-meat animals, and milk are compared. Per capita consumption of fats and oils and the relationship of oil value and meal value are also discussed. U.S. data are referred to extensively because of this country's important role in world food supply

Production-Consumption Relationships of Edible Fats and Proteins from Animals and Oilseeds

Excerpt from the Introduction: The information in this paper was developed as a part of a study to determine the influence of world fat and oil consumption on protein supply. The paper concerns past, present, and future world and U.S. production of edible fats and oils as they influence edible protein supplies from commodities that yield both types of products. The production and values of fat and oil and protein from various oilseeds, red-meat animals, and milk are compared. Per capita consumption of fats and oils and the relationship of oil value and meal value are also discussed. U.S. data are referred to extensively because of this country's important role in world food supply

Consequences of isostructural main-chain modifications for the design of antimicrobial foldamers: helical mimics of host-defense peptides based on a heterogeneous amide/urea backbone.

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