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

Table of Contents


Ecological attributes are those aspects of an aquatic assemblage or community that correspond to the structure and function of that assemblage or community for a given condition.
Cumulative impact
The impact on the environment caused by a human activity which results in an incremental impact in combination with other past, present and reasonably foreseeable future human activities.
Ecological component
Ecosystems consist of various non-living abiotic and living biotic components. The abiotic components of an ecosystem include various physical and chemical factors.
Ecological risk assessment
The process that evaluates the likelihood that adverse ecological effects may occur or are occurring as a result of exposure to one or more stressors.
The 2004 Convention on Biological Diversity defines the term ecosystem simply as a dynamic complex of plant, animal and micro-organism communities and their non-living environment interacting as a functional unit. The concept is applicable at any scale, from the planet as an ecosystem to a microscopic colony of organisms and its immediate surroundings.
Ecosystem based management (EBM)
Ecosystem-Based Management (EBM) is the management of human activities to ensure that marine ecosystems, their structure (e.g.,, biological diversity), function (e.g.,, productivity) and overall environmental quality (e.g.,, water and habitat quality) are not compromised and are maintained at appropriate temporal and spatial scales.
Ecosystem services
Ecosystem services are the benefits people obtain from ecosystems. These include provisioning services such as food and water; regulating services such as regulation of floods, drought, land degradation, and disease; supporting services such as soil formation and nutrient cycling; and cultural services such as recreational, spiritual, religious and other nonmaterial benefits.
The term endpoint is used to illustrate the ecosystem component/function and/or social, cultural or economic value that needs maintenance or protection.
Environmental effect
An environmental effect represents changes to the state of the environment caused by natural or human-based actions.
Environmental indicator
An environmental or a state indicator is a numerical value that helps provide insight into the state of the environment or human health. Indicators are developed based on quantitative measurements or statistics of environmental condition that are tracked over time.
Human activities
Human activities, sources or sub-activities are entities or actions that are released or impose pressures on the environment.
An impact is a measurable change to an ecosystem component/function. An impact can be positive or negative.
Limit reference point
The Limit reference point is the stock level below which productivity is sufficiently impaired to cause serious harm to the resource but above the level where the risk of extinction becomes a concern.
Measurable endpoint
A measurable ecological, social, cultural or economic value that is related to the valued component chosen as the endpoint. A measurable endpoint establishes the link between an endpoint and the management or conservation objective identified by resource managers.
Any chemical, physical or biological entity that can cause an adverse effect on a measurable endpoint(s).
Pressure indicators
Pressure indicators measure the factors that cause changes in the ecosystem.
Regional environmental assessment (REA)
Regional Strategic Environmental Assessment (R-SEA) is a process designed to systematically assess the potential environmental effects, including cumulative effects, of alternative strategic initiatives, policies, plans, or programs for a particular region.
Risk refers to the uncertainty that surrounds future events and outcomes. It is the expression of the likelihood and impact of an event with the potential to influence the achievement of an organization's objectives.
Social, cultural or economic values
Social, cultural or economic values (market or non-market) that can be affected by a change in an ecosystem component or function.
Social, cultural or economic dependencies
Social and economic activities that rely on valued ecosystem components or ecosystem goods and services for their success.
A target is a clearly defined development goal that should be “SMART” (i.e., specific, measureable, achievable, realistic and time related).
A limit of change in an ecosystem component/attribute which if exceeded, requires a change in management for protecting the ecosystem component/attribute. A threshold is defined here as a point between alternate regimes in ecological or social-ecological systems. When a threshold along a controlling variable in a system is passed, the nature and extent of feedbacks change, such that there is a change in the direction in which the system moves. A shift occurs when internal processes of the system (e.g., rates of birth, mortality, growth, consumption, decomposition, leaching, etc.) have changed such that the variables that define the state of the system begin to change in a different direction, towards a different attractor. In some cases, crossing the threshold brings about a sudden, large and dramatic change in the responding variables, whilst in other cases the response in the state variables is continuous and more gradual.
Valued ecosystem component (VEC)
Any part of the environment that is considered important by a proponent, members of the public, scientists and governments. Importance may be determined on the basis of cultural values or scientific concerns.
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