The environmental stress response of invertebrates was examined using wetlands in the Alberta oil-sands region as a model. Wetlands in this region occur naturally or they have been affected by oil-sands mining process materials such as mine-tailings, or saline process water. These materials can be toxic to aquatic organisms due to their high concentrations of sulphate ions, ammonia, polycyclic aromatic hydrocarbons (PAHs) and naphthenic acids. Wetlands are classified as either young or mature, and as having low or high sediment organic content. This study examined food web dynamics and structure in wetlands using stable isotopes to determine the effects of stress on ecological communities. Primary and secondary production in the wetlands was measured along with invertebrate diversity in order to determine a relationship. The maximum trophic position was determined using stable carbon and nitrogen isotopes to indicate food chain length which is influenced by energetic constraints, ecosystem size and stressors. The study quantifies the dynamics of vital links between the responses to environmental pressures in aquatic systems and the effects on terrestrial ecosystems