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D2.3 Transboundary impact assessment in the north-western Iberian Peninsula


Sustainable development and specifically Sustainable Blue Economy asks for an Ecosystem Based Approach (EBA) to Maritime Spatial Planning (MSP) to identify the utilization of marine space for different uses in the most efficient and sustainable way. Therefore, addressing Cumulative Effects/Impacts (CE/CI) is an essential part of this process as it supports the identification, description and evaluation of significant effects of implementing the plan on the marine environment. Cumulative effects are a key aspect of Strategic Environmental Assessment (SEA) for Maritime Spatial Planning (MSP) and also to comply with the objectives of the Marine Strategy Framework Directive (MSFD). Cumulative effects are defined as “changes to the environment that are caused by an action in combination with other past, present and future human actions” (Casimiro, D. et al., 2021; Hegmann et al., 1999). This document describes a proposed methodology for Cumulative Effects Assessment (CEA) to assess cumulative impacts/effects at a transboundary scale. The work was conducted in a specified case study in the north-western Region of the Iberian Peninsula in a cross-border area between Portugal and Spain.

Application in MSP:
Type of Issue:
Type of practice:
Stage of MSP cycle:
Cross-border / trans-national aspect:
Coherence with other processes:
Key words:

Questions this practice may help answer:

  • Which ecological indicators are implemented in the framework of Cumulative Effect Assessment?
  • Where in the north-western Iberian Peninsula are anthropic impacts concentrated?
  • How are Marine Protected Areas affected by the impacts of marine activities?

Implementation Context:

This paper was drafted in the framework of the SIM ATLANTIC project which aimed at supporting the establishment and implementation of maritime spatial planning (MSP) in five European Atlantic countries (France, Ireland, Portugal, Spain and the United Kingdom).

Aspects / Objectives:

This study provides methodology for Cumulative Effects Assessment (CEA) to assess cumulative impacts/effects at a transboundary scale based on the north-western Iberian Peninsula.


For the purpose of this study two main groups of ecological components were considered as receptors of the pressures produced by the activities (benthic habitats and functional groups of pelagic species). The analysed activities were selected depending on their inclusion in the MSP processes in both Spain and Portugal. The framework developed was divided in 3 steps:

  1.     identification of the most likely pressures resulting from activities within the study area;
  2.     a sensitivity assessment of the ecological components present in the study area;
  3.     a calculation of the Cumulative Impacts.

Main Outputs / Results:

This study provides insights on how Cumulative Effect Assessment can contribute to the development of an Ecosystem Based Approach for MSP. It also provides solutions to improving the implemented methodology.


This practice focuses on the north-western Iberian Peninsula, but the methodology implemented could inspire similar approaches in other areas.

Responsible Entity:

SIMAtlantic Project

Costs / Funding Source:

This document was produced as part of the SIMAtlantic project (Grant Agreement: EASME/EMFF/2018/