Research Document 2021/079

Review of Pathways of Effects (PoE) diagrams in support of FFHPP risk assessment

By Brownscombe, J.W. and Smokorowski, K.E.

Abstract

Fisheries and Oceans Canada’s Fish and Fish Habitat Protection Program (FFHPP) has a regulatory regime in place to avoid, mitigate and offset the negative effects of projects on fish and fish habitat. To understand these negative effects, Pathways of Effects (PoE) diagrams are used to describe linkages between the works, undertakings, and activities (WUAs), the ‘pressures’ by which WUAs affect the ecosystem, and the resulting ‘endpoints’ affecting fish and/or fish habitat. Twenty original PoE diagrams have been recently combined into four proposed diagrams focused on 1) land-based WUAs, 2) energy and noise producing WUAs, 3) in-water WUAs, and 4) WUAs affecting water flow. Here we provide a selective review of these four PoE diagrams to assess whether the pressures, pathways, and endpoints are valid, comprehensive, and complete. A range of support levels were found for pressure pathways, identifying well supported connections, those that have a theoretical basis but lack extensive research, those with potential alterations for improved comprehensiveness and accuracy, and those lacking support. Numerous recommendations are included for alterations to terminology and addition or removal of linkages and nodes. Related resources are included in a database that may serve to support the application and further development of additional PoE diagrams. It is challenging to encompass the wide variety of complex impacts that human activities may have on fish and fish habitat, and we recognize a trade-off between the comprehensiveness and tractability of these diagrams in communication and decision making. Consideration of this trade-off while integrating these recommendations is important to ensure maximum validity and applicability by FFHPP. To employ ecosystem-based management accounting for the cumulative effects of activities on ecosystem state, there is a need to further identify interconnectivity amongst these PoE diagrams, as well as how various pressure pathways interact to produce cumulative effects.

Research Document 2021/079 (PDF, 2,032 KB)

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