Figure 1. Conceptual Framework: integrating the behavior,
physiology, and bioenergetics of coping with multiple stressors. Energy
is allocated among key components (thick arrows) leading ultimately to
fitness effects; the 4 key trade-offs are color-coded. Assimilated
Energy pays the energy cost of basal metabolism (BMR), and the remaining
Net Energy Gain Rate is subdivided into three competing energy sinks
(yellow rectangles, trade-off 3). The energy flow into response to
stressors powers two types of escape plus tolerance (green rectangles,
trade-off 4). Stressor Tolerance provides energy for the mechanisms to
avoid when possible or otherwise to mitigate the stressor effects. These
mechanisms may be behavioral or physiological or both (blue rectangles,
trade-off 1); they are triggered by the Stressors and ameliorate them
while potentially interacting with each other. Activity creates a
trade-off between Energy Assimilation Rate and Survival (pink
rectangles, trade-off 2). Food Availability and Risk of Predation or
Other Mortality sources potentially increased by activity act on these
linkages. Survival and Growth/Reproduction are influenced by the
Stressors and Coping Mechanisms, jointly yielding Fitness.
Figure 2 . Categories of multiple stressor combination types
according to degrees of feedback between stressor(s) and focal organisms
from A) no feedback, B) uni-directional feedback and C) bi-directional
feedback.