We examined whether chemically mediated risk perception by prey and the effects of changes in prey behavior on basal resources vary as a function of the amount of prey biomass consumed by the predator. We studied these issues using a tritrophic system composed of blue crabs, Callinectes sapidus (top predator), mud crabs Panopeus herbstii (intermediate prey), and oysters Crassostrea virginica (basal resource). Working in a well characterized field environment where experiments preserve natural patterns of water flow, we found that biomass consumed by a predator determines the range, intensity and nature of prey aversive responses. Predators that consume large amounts of prey flesh more strongly diminish consumption of basal resources by prey and exert effects over a larger range (in space and time) compared to predators that have eaten less. Less well-fed predators produce weaker effects, with the consequence that behaviorally mediated cascades preferentially occur in refuge habitats. Well-fed predators affected prey behavior and increased basal resources up to distances of 1–1.5 m, whereas predators fed restricted diet evoked changes in prey only when they were extremely close, typically 50 cm or less. Thus, consumptive and non-consumptive effects may be coupled; predators that have a greater degree of predatory success will affect prey traits more strongly and non-consumptive and consumptive effects may fluctuate in tandem, with some lag. Moreover, differences among predators in their degree of prey capture will create spatial and temporal variance in risk cue availability in the absence of underlying environmental effects.
Despite the ubiquity of coastal infrastructure, it is unclear what factors drive its placement, particularly for water access infrastructure (WAI) that facilitates entry to coastal ecosystems such as docks, piers, and boat landings. The placement of WAI has both ecological and social dimensions, and certain segments of coastal populations may have differential access to water. In this study, we used an environmental justice framework to assess how public and private WAI in South Carolina, USA are distributed with respect to race and income. Using publicly available data from State agencies and the US Census Bureau, we mapped the distribution of these structures across the 301 km of the South Carolina coast. Using spatially explicit analyses with high resolution, we found that census block groups (CBGs) with lower income are more likely to contain public WAI, but racial composition has no effect. Private docks showed the opposite trends, as the
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