Creating the Marine Habitat Map
Unlike terrestrial landscapes, mapping marine habitats presents numerous challenges given the costs, logistics and limitations of accessing the ocean. The best techniques for marine habitat mapping rely upon predicting where habitats are located from existing information.
The statewide marine habitat map was created from available habitat observations recorded in Victoria’s waters, combined with predictive modelling and mapping techniques that synthesis existing information. The below steps outline the process of creating the marine habitat map.
The building blocks of the habitat map are 32,998 locations across state waters where habitats have been physically observed and recorded (i.e. ground-truth records). Habitat observations have been included from a variety of sources including localised habitat mapping, monitoring programs, impact assessments and historical surveys, and have been classed according to Victoria’s Combined Biotope Classification Scheme (CBiCS). All habitat observation records are available from the ‘Biotope Atlas Tool’ in CoastKit.
Twenty-eight environmental properties that are considered related to habitat characteristics were incorporated into the modelling process. These included bathymetry, productivity, temperature, sediments, waves and currents. Environmental properties were mapped at a high resolution across the state and assisted the model to predict where habitats occur.
To predict the distribution of habitats across Victorian waters the powerful Random Forest machine learning algorithm was applied. Random Forest is considered an effective modelling method for marine habitats and biodiversity with high performance and application across the globe.
Existing marine habitat maps that provide high resolution mapping across small sections of the state were integrated into the statewide map. The final map comprises 83% of habitat area from predictive habitat modelling (Step 3), with the remaining 17% from former habitat maps.
The statewide habitat map represents 24 distinct habitats (CBiCS Level 3). Importantly, these 24 habitats encompass a range of species, some of which may be unique, rare or vulnerable. Victoria’s waters comprise a diversity of habitats, with the open coast dominated by sand and muddy sand with patches of infralittoral rock. The central open coast features rhodolith beds, with rocky habitats characterising the western coast in contrast to the eastern coast with vast sand and mixed sediment habitats. Victoria bays, and inlets are a complex assemblage of habitats, with coastal saltmarsh and reedbeds, mangroves, muddy habitats, communities of macroalgae, and significant seagrass beds across Port Phillip Bay, Western Port and Corner Inlet.
Applying the Marine Habitat Map
The statewide map provides broad knowledge of 24 marine and coastal habitat types across the state to support:
- Large-scale habitat management (>25m)
- Habitat condition assessments
- Marine Spatial Planning
- Strategic Management Prospect (SMP)
- Feature Activity Sensitivity Tool (FeAST) risk assessments
The map provides fundamental knowledge for management decisions across Victoria's marine and coastal waters, and a baseline of information for future data to build upon.
Page last updated: 23/03/23