Occurrence & Usage

What is Occurrence & Usage? 

By modelling the spatial and temporal distributions of animals and their abundance/density across space and time, we can look at trends and understand how species use different areas before human activities begin. These baseline maps help show natural variation and are an important part of Environmental Impact Assessments for activities such as renewable energy development, or offshore military training activities (i.e. using naval sonar). 

As well as studying occurrence and abundance/density at given locations, we monitor the ways in which animals use different areas of their environment with visual, acoustic, and biotelemetry data. Detailed understanding of when animals commonly use specific regions for specific activities can significantly aid modelling the consequences of environmental impacts.

What has CREEM Contributed? 

At CREEM, we’ve developed guidance and tools to support survey design, data analysis and density surface modelling: 

• MRSea (Marine Renewables Strategic Environmental Assessment). MRSea is a spatially adaptive density surface modelling technique to analyse animal distributions using generalised additive models. While it was created for offshore renewables, it can also be used for other occurrence applications, such as studying animal home ranges and resource use from GPS tracking data. 
• dsm R software package, which implements spatial models to calculate spatially explicit estimates of animal abundance from distance sampling data.  For more information on dsm and distance sampling see here. 
• MRSeaPower, an R package that helps scientists design monitoring surveys and test how well they can detect changes in animal abundance or distribution during and after development activities (prospective assessments).  

We have also developed methodology for integrating digital aerial survey data and passive acoustic data for marine mammals.  

What species are these methods used for? 

The majority of CREEM research on species occurrence and space usage relates to the marine environment, particularly marine mammals and seabirds.  We have been part of several large-scale projects mapping seabird and marine mammal distributions at both national and international scales. These include: 

• Danish Risk Mapping. Mapping relative risk to seabirds from offshore wind energy developments in Danish waters. This project included distribution mapping for 29 seabird species/species groups.  
• POSEIDON project (Planning Offshore Wind Strategic Environmental Impact Decisions): mapping marine mammals and seabird species in UK territorial waters. 
• The Joint Cetacean Protocol (JCP): mapping 7 marine mammal species over a 17-year period from the continental shelf edge west of Ireland to the Kattegat in the east. 
• Identification of Marine Protected Areas in Scottish territorial waters for three cetaceans and basking sharks.  

Who in CREEM works on these methods? 

• Saana Isojunno
• Lindesay Scott-Hayward
• Tiago Marques
• Cornelia Oedekoven
• Danielle Harris
• Eiren Jacobson
• Louise Burt
• Monique MacKenzie
• Debbie Russel
• Charles Paxton
• Theoni Photopoulou
• Enrico Pirotta

PhD Students: Sam Durston 

A few relevant and recent publications by CREEM staff: 

Scott-Hayward, L.A.S., Mackenzie, M.L., Walker, C.G., Shatumbu, G., Kilian, W., du Preez, P., Hauptfleisch, M. and Cloete C. (2025). Assessing the distribution pattern of elephant (Loxodonta Africana) carcasses in Etosha National Park and implications for management. Namibian Journal of Environment 10, p.1-12. 

Isojunno, S., Scott-Hayward, L.A.S., Pedersen, C.L., Thomsen, H., Chetcuti, J., Frederiksen, M., Bregnballe, T., Sterup, J., MacKenzie, M. Petersen, I.K. (2025). Mapping relative risk to seabirds from offshore wind energy developments in Danish waters. Aarhus University, DCE – Danish Centre for Environment and Energy, 101 pp. Technical Report No. 367. 

Harris, D., Chudzińska, M., Jacobson, E., Brown, A., Burt, L., Macleod, K., Marques, T.A., Marshall, L., Oedekoven, C.S., Scott-Hayward, L.A.S. and Thomas, L. (2024) Methodology for Combining Digital Aerial Survey Data and Passive Acoustic Baseline Data. Report number CREEM-2024-02. Provided to Scottish Government, Nov 2024 (Unpublished)  

Ryder, M., Booth, C., Oedekoven, C., Marques, T., Joy, R., Harris, D. (2024). Passive Acoustic Monitoring Power Analysis: A Tool for Designing an Acoustic Monitoring Program. In: Popper, A.N., Sisneros, J.A., Hawkins, A.D., Thomsen, F. (eds) The Effects of Noise on Aquatic Life. Springer, Cham.

Scott-Hayward, L.A.S., Mackenzie, M.L., Ashe, E. and Williams R. (2015). Modelling Killer Whale feeding behaviour using a spatially adaptive Complex Region Spatial Smoother (CReSS) and Generalised Estimating Equations (GEEs). Journal of Agricultural, Biological and Environmental Statistics 20, 305–322.  

Walker C.G., Mackenzie M.L., Donovan C., O’Sullivan M. (2011). SALSA – A Spatially Adaptive Local Smoothing Algorithm. Journal of Statistical Computation and Simulation, 81(2), 179-191.