Bioregionalisation for the SW Pacific and Indian oceans

Lead: Piers Dunstan, CSIRO


Biogeographic regionalisation – or bioregionalisation for short – is a process by which the physical and biological variability in the environment is analysed, classified and mapped into spatial units, each with distinct biological, ecological and physical properties.  The process simplifies the complex spatial organisation in nature (e.g., habitats) and represents it on a map to improve understanding and inform decision making.  Biogeographic maps of provinces are an essential tool for the sustainable use and conservation of marine biodiversity (e.g., for developing an ecologically representative and coherent network of marine protected areas).

As a step towards ensuring the connectivity, sustainable use and conservation of marine biodiversity, bioregionalisation exercises for the western South Pacific Ocean and the Indian Ocean will be conducted.  This approach builds upon that developed and established by the Australian national marine bioregionalisation process, undertaken by CSIRO.  By collating and integrating available physical and biological information in a systematic manner, a set of biogeographic provinces are identified that reflect habitat diversity, biological diversity and any interaction between the two.  These outputs are compatible with those from similar exercises around the world.

Stakeholders from the region, including data holders, marine resource users, public and private sector environmental agencies, and relevant national and international governance authorities, are to be included at various stages in the process, to ensure that the final outcome of the work is a set of appropriate, inclusive, integrated and transparent management tools for the region.


  • To develop a bioregionalisation for the western South Pacific Ocean and the Indian Ocean.
  • To promote connectivity and ecological coherence in spatial management.


A stepwise approach to the completion of this work includes the following activities:

  • Identification, acquisition and collation of physical and biological datasets available in the region of interest, thereby rationalising their format for inclusion in the process.  Many such datasets have already been compiled during dedicated regional workshops to facilitate the description of EBSAs. Newly available datasets are to be incorporated into the process throughout the duration of the project.
  • Application and further refinement of existing methods, starting with the processing of physical datasets to produce a physical regionalisation that informs the analytical options available to the next steps.
  • Production of a draft bioregionalisations for selected taxa to illustrate the approach applying existing methods and to encourage engagement with the process and its potential.
  • Organisation of regional international workshops to engage regional stakeholders (e.g., data holders, the scientific community, industry and government) to develop bioregionalisations for the Indian and western South Pacific Oceans.
  • Further consultation with regional stakeholders to verify that the boundaries generated by the bioregionalisation process are legitimate and acceptable.
  • Engagement with regional, national and international authorities to ensure that the results and limitations of the bioregionalisation exercise are understood and used to optimise the effectiveness of local, national and regional marine spatial management plans.


There are many spheres of science, industry and civil society in which a state-of-the-art bioregionalisation would be useful.  For example, the resultant maps from this work will inform the placement of marine protected areas, as well as the choice of spatial or temporal management measures on fishing, mining, marine traffic or industrial discharge.  Understanding the interacting characteristics of different bioregions will allow the tailoring of management practices to ensure sustainable use and conservation of biodiversity across each of the ocean basins.  These examples represent and embody the CBD’s objectives of conservation, sustainable use and fair sharing of the benefits arising from the utilisation of biodiversity and associated natural resources.

Progress to date

Regionalisation of the Indian and southern Pacific Oceans using only data on physical variables (i.e., water depth, seabed substrate type, water chemistry, flow dynamics, etc.) has been completed.  This can now be used to place information on biological variables (i.e., identity, abundance and range of different species) into context.  Mathematical tools with which to combine and analyse all this spatially and temporally explicit information have been reviewed and, in most cases, redeveloped to accommodate the complexities of dealing with a dynamic and three-dimensional ocean.  Regional experts and biological data holders from both ocean basins have gathered at dedicated workshops, to combine their resources and produce maps of biogeographies for selected taxa.

As a result of activities so far, in the Indian Ocean, 72 benthic and 14 pelagic bioregions have been identified, and in the southern Pacific Ocean, 35 benthic and 16 pelagic bioregions have been identified.  Each of these bioregions has been described, mapped, and a qualitative ecosystem model that identifies the key pressures acting on it has been created.

All of these outputs are in the final stages of being reviewed for consistency and checked against reality, through direct observation of their predictions in the field.  Once validated, they will be finalised and available for dissemination and application across the region, although preliminary results are already being used and ‘road tested’ in a handful of localised applications.