Distribution modelling of the Shetland Islands benthic habitats

Shetland’s marine environment, a diverse ecosystem, is important for various habitats and species. This report presents the results of a habitat distribution model developed for Shetlands inshore marine environment (MLWS to 12nm offshore), providing detailed potential biotope distribution information. These results provide the foundational work for a range of future management applications, including the analysis of habitat-marine user interactions.
Within Shetland waters a total of 127 biotopes (habitats) were identified and grouped into 28 distinct categories. A focus was also made on Priority Marine Features (PMFs) within these groupings. Environmental data layers (13 in total) were identified for analysis. These layers included bathymetry information, sediment data, seabed variables, and tidal velocities. Using Distribution Models, a likelihood of occurrence habitat map for each identified biotope groups were created.
Multiple biotopes were studied, from 'high energy circalittoral rock' to 'offshore circalittoral mixed sediment', and their distributions ranged from localised areas to expansive regions spanning significant portions of the Shetland area.
The distribution model showed high predictive capabilities and provided insights into the predictive capacities for biotope distribution, with higher habitat suitability often aligning with actual record locations. The scale of biotope distributions, ranging from localised to widespread, indicates potential adaptabilities and preferences across Shetland.
Recommendations:
• Ongoing monitoring and database updates for future predictive distribution models, especially around areas of data deficiency.
• Target sensitive habitats for data collection to increase the robustness of the model within marine management.
• Ground-truthing of the current model.
This in-depth analysis highlights the predicted habitat suitability and distribution of various biotopes across Shetland. Improving upon previous models through the use of Shetland specific environmental variables and the most up to date biotope records, whilst leveraging both historical data and modern predictive modelling techniques. This report serves as a pivotal reference for future marine management endeavours in the Shetland region.