Pathways of Effects - National Guidelines
Illustrating the links between human activity and its potential impact on aquatic ecosystems

Table of Contents


Table 1: Draft Integrated Management / Ecosystem-based Management planning process

3.1 Role of PoEs

In addition to the reports and guides described in the previous section, managers and regulators also need tools, such as environmental and risk assessment processes, to identify management priorities. PoEs can guide these processes by providing the necessary science-based foundation for decision-making (as highlighted in the draft IM/EBM process framework in Table 1).

PoEs are also effective communication tools that inform, educate, involve and engage ocean users, governments, and other affected and interested parties.

3.2 What is a PoE model?

A PoE model is a conceptual representation of fact-based relationships between human activities and their associated sub-activities, the pressures and the environmental effects or impacts they may have on a specific ecological or biological endpoint.Footnote 2 The alteration of the endpoint may have consequences on ecosystem goods and services, and ultimately the socio-cultural and economic activities and values that rely upon these goods and services. Figure 1a illustrates the elements in a PoE model.

Figure 1b provides a concrete example of what PoE elements represent and the relationships among them. The human activity, oil and gas, and one of its sub-activities, exploration drilling, may potentially introduce heavy metal contaminants in the water column via the discharge of mud and/or cuttings. One of the resulting impacts may be damage to the respiratory organs of fish such as Arctic char (endpoint). If the Arctic char population in the vicinity of the contaminated water column is affected, then the ecosystem may not be able to provide the fish biomass necessary for harvesting purposes. In turn, direct consequences on commercial and domestic Arctic char fisheries and indirect consequences on fish processing plants may occur.

PoE models consist of diagrams like those in Figure 1, as well as a narrative that describes the relationships among the elements along with the rationale for their selection.

Figure 1a: PoE main elements
Figure 1b: Example

3.3 Benefits of a PoE model

The benefits of using a PoE model are numerous. In particular, PoEs can inform decision-makers by:

  1. Illustrating potential impacts:
    • linking human activities and ecological components to ecosystem services and social, cultural and economic values (endpoints);
    • aiding strategic management planning related to cumulative effects that arise from activities in a place-based context;
    • serving as a check list for potential effects when reviewing the design/mitigation of a particular sector’s activities in a regulatory or an environmental assessment context; and
    • helping managers to understand an issue fully and identify key areas where mitigation to break or minimize the pathway may be most effective.
  2. Supporting communication:
    • with the public, managers, practitioners, regulators and affected parties;
    • with project proponents (particularly with regards to potential effects of a proposed project, as well as the information and monitoring required for project reviews and ongoing evaluation); and
    • with stakeholders (facilitation of participation through a transparent, structured and scientifically validated review process).
  3. Facilitating the identification of gaps and needs:
    • policy and regulatory gaps:
      • identification of requirements for new policy, regulatory and non-regulatory measures;
      • identification of responsible authorities who should be involved in decision-making processes due to their specific mandates for the proposed activities or potentially affected ecological and/or social, cultural and economic values in area of interest; and
    • research needs (e.g., areas of limited or unknown effects on ecosystem components).
  4. Providing additional benefits:
    • creating bridges between aquatic terrestrial, marine and coastal management by illustrating impacts of land-based activities on marine environments.

3.4 PoE design

Figure 2: Examples of PoE design, terminology and labels used in conceptual modeling

Figure 2 (following page) illustrates the various terminologies, labels and layouts used in conceptual modelling. On the left, DFO‘s Habitat and Aquaculture Management programs use a PoE terminology composed of three main elements. Oceans programming – in the centre – uses a more detailed terminology. This is closely linked to the international driving forces-pressures-state-impacts-responses (DPSIR) nomenclature that is illustrated on the right. Depending on the origin of the model, different terminology may be used.

The DPSIR framework, an extension of the Organisation for Economic Co-operation and Development’s 1999 Pressure State Response framework, was originally developed by the United Nations Environment Program (UNEP) and adopted by the European Environmental Agency (EEA) to assess and manage environmental problems. It is a general framework for organizing information about the state of the environment, and assumes cause-effect or correlative relationships between interacting components of social, economic and environmental system. These include:

  • Driving forces of environmental change (e.g., industrial production);
  • Pressures on the environment (e.g., discharges of waste water);
  • State of the environment (e.g., water quality in rivers and lakes);
  • Impacts on population, economy, ecosystems (e.g., water unsuitable for drinking);
  • Response of the society (e.g., watershed protection).

The PoE approach outlined in this document is consistent with the DPSIR framework. However, the driver element of the DPSIR is further divided into two elements: human activity and sub-activities. This adds specificity to the type of activity that may cause pressures. Endpoints are also added in the DFO Oceans PoEs because they structure/align the assessment to address management concerns. Compared with DPSIR, DFO PoEs do not include institutional responses to a pressure (e.g., code of practice, mitigation measure, best management practice (BMP), regulation or others), although these may be identified later in the management process.

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