Science Advisory Report  2016/003

Evaluation of Hierarchical Marine Ecological Classification Systems for Pacific and Maritimes Regions


  • Two applications of a conceptual hierarchical marine ecological classification system (HMECS) framework (DFO 2013) were reviewed at a Zonal Peer Review meeting September 29 to October 2, 2015. The conceptual framework was applied independently to disaggregate the Fisheries and Oceans Canada (DFO) Pacific Region Northern Shelf and Southern Shelf Bioregions (PNSB and PSSB) and the DFO Maritimes Region Scotian Shelf Bioregion (MSSB) into smaller hierarchical spatial units based on ecological attributes.
  • A harmonized classification for benthic ecosystems based on the Pacific and Maritimes Region results was developed and is recommended for future benthic classification applications. The harmonized HMECS represents a revision to the classification proposed in DFO (2013) and comprises 11 levels. Approaches for populating Levels 4-7 (below the Bioregion) were developed. Although this classification is hierarchical in terms of spatial scales, not all units or levels are perfectly nested within the level or scale above. For example, a single Geomorphic unit (Level 5) such as a trough, may span several Biophysical units (Level 4).
  • The Pacific and Maritimes classifications represent variations of the same approach. The Pacific Region classification at the Biophysical level (Level 4) is based primarily on biological and environmental data, and the Maritimes classification is based primarily on environmental data that are weighted with information from previous biological analyses in the region. It should be noted that methods other than those reviewed through this process may be appropriate for classifying areas into ecological units at different levels of the hierarchy.
  • The methods used to develop and populate levels in the harmonized HMECS, and the resulting delineation of Biophysical (Level 4) and Geomorphic (Level 5) units in classification maps for the Pacific Region, are robust and suitable for their intended purpose of supporting and informing marine spatial planning initiatives with respect to patterns in habitat and community diversity at multiple spatial scales, particularly the achievement of the representativity and replication criteria for MPA network design. The boundaries between Biophysical units may represent transition zones, rather than absolute spatial distinctions between habitats/communities considering the scale of the analysis, and may be an important Biophysical unit on their own.
  • For the Maritimes Region, due to differences in the oceanography and bathymetry layers, which limited interpretation of the resultant Biophysical units layer, it was agreed that it would be better to use the oceanography and bathymetry layers separately in future marine spatial planning initiatives in the region rather than using the Biophysical units layer. An investigation is recommended of spatial patterns in species composition and multivariate environmental data over the entire Scotian Shelf in Maritimes Region to establish whether similar biogeographic and ecological patterns of species assemblages persist at the Biophysical scale, i.e., to provide some validation of the Biophysical units defined by environmental data alone.
  • A coastal/nearshore/inshore “unit” in the Biophysical level (Level 4) has not yet been identified in the Pacific Region, because there were insufficient data at the appropriate scale. Delineation of this unit may influence the boundaries of the adjacent Biophysical units.
  • The Benthic Terrain Modeler (BTM) tool was used in the Pacific Region to identify Level 5 Geomorphic units on the seabed that are presumed to have important species associations; however, these biological correlations have not been validated. Present results are likely sufficient to begin marine spatial planning, but future work to more fully characterize these classifications according to their species associations is recommended.
  • A bottom patch model using substrate data to describe habitat in nearshore waters < 50 m deep was proposed but not evaluated for populating the Level 6 Biotope units in the Pacific Region. Further work is recommended to investigate its application in deeper waters, and to deal with issues of scale. Other methods that incorporate biological information may also be appropriate and should be identified and explored.
  • A method for Biotope classification in the Maritimes Region based on substrate characteristics was presented for the coastal Biophysical unit only, as coastal substrates are the only high resolution data available region-wide. It is recommended that substrate models be applied for classifying Biotope units when biological data are not available.
  • Level 7 (Biological Facies) could be represented by focal species or habitats because the full range of biological data with sufficient resolution and scale are not available at present in either Region. It is recommended that all available distribution data for fine-scale Level 7 Biological Facies units (e.g., Glass Sponge reefs, Eelgrasses, and Kelp beds) should be collated, and models developed and evaluated to predict the distributions of these habitats in PNSB and PSSB.
  • The development and application of a classification system for pelagic systems using the harmonized benthic HMECS as a template is recommended.
  • Neither the Maritimes nor the Pacific Region classifications included the intertidal zone, although this unit has been classified independently in each Region. Because the intertidal zone may have value for some management processes, it is recommended that further investigation into the appropriate integration of these classifications into a coastal/nearshore/inshore "unit" be conducted in the future.
  • Geospatial databases to manage the spatial data and layers are an essential component of the harmonized HMECS. Ongoing support to maintain this database is important for the successful application of HMECS to inform management decisions. Collaboration among DFO programs engaged in marine spatial planning initiatives (e.g., MPA planning, Marine Preparedness and Response, Aquaculture, Fisheries Protection) is recommended to develop an accessible and comprehensive geospatial database and to avoid duplication of efforts and inconsistencies in products.
  • In order to populate the higher resolution levels of the HMECS, it is recommended that multiple datasets, including (but not limited to) third party environmental assessments, local ecological knowledge, First Nations knowledge, aquaculture siting studies, academic studies, and museum collections be reviewed to maximize the inclusion of biological data where possible and appropriate.

This Science Advisory Report is from the September 29 to October 2, 2015 zonal peer review on the Evaluation of Hierarchical Marine Ecological Classification Systems for Pacific and Maritimes Regions. Additional publications from this meeting will be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Schedule as they become available.

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