Connecting individual level processes to ecosystem management and restoration efforts

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To support ecosystem restoration and sustainable management efforts, links between individual responses to disturbance with community structure and pathways and/or rates of energy flow in aquatic ecosystems must be better understood. Over a century of industrial activity without considering environmental impacts has led to widespread and often negative changes in aquatic ecosystems. The introduction of environmental regulations by governments to limit industrial emissions has allowed some recovery, but biological recovery is rarely achieved, typically lagging well behind chemical recovery. Impacts of contaminants are mostly documented at the organismal level (e.g., growth, behaviour, cellular and metabolic responses), but management efforts in impacted and recovering ecosystems are applied at the population and ecosystem level. This mismatch between impact assessment and management highlights the need to connect individual-level responses to the ecosystem level at which management actions are applied. Further, ecosystem coupling (e.g., via fish or resource movement) and its contribution to ecosystem resilience have framed a conceptual model of adaptive capacity in the Laurentian Great Lakes, which also highlights drivers of offshore fish production as a major knowledge gap. Metabolic changes at the individual level (e.g., activity and resting metabolism) are predicted to have demographic consequences, resulting in population- and ecosystem-level changes via consumer abundance and prey consumption. This in turn may alter the community composition of ecosystems, which can alter food chain length, energy transfer efficiency and contaminant accumulation in aquatic food webs. During the next 5 years, Dr. Rennie will lead a research group to quantify relationships between individual-level metabolic changes to population- and ecosystem-level processes, using complimentary approaches in both whole ecosystem assessments and manipulative whole-lake experiments. Building on ongoing research and initiating new lines of investigation, relationships between trophic energy transfer and individual metabolic costs will be evaluated in two whole-lake experiments; one examining the impacts of microplastic additions, anticipated to alter energy transfer through fish metabolic rates and changes in community structure, and another food web manipulation/ecosystem restoration experiment where freshwater shrimp (Mysis diluviana) are being re-established after a 40+ year absence. Mechanistic hypotheses of the role of ecosystem subsidization (via movement of fish and/or resources) on offshore freshwater reef productivity will be evaluated using hydroacoustic, stable isotope and remotely operated vehicle technologies. This innovative research will advance the fields of ecology, evolution and aquatic science, providing critical tools for policy makers and resource managers tasked with restoring and monitoring aquatic ecosystems in the face of global environmental change.