IAP-25-060

Occupancy, density and the ecology of terrestrial British mammals

Mammals include species of ecological, economic and cultural importance. Determining the factors that drive their abundance and distribution, and developing effective management, rely on sustained and widespread monitoring. Britain boasts a rich history of detailed and informative studies of specific mammal populations. Over the same period, however, effective monitoring of the wide range of terrestrial mammal species has been lacking, exacerbated by the fact that many species occur at low densities, and are nocturnal or otherwise elusive. Consequently, calls for improved monitoring to underpin conservation and management have a long history.

Recent years have brought some notable declines in British mammals, including hedgehogs, weasels and wildcats. At the same time, invasive non-native species, including mammals such as muntjac and grey squirrel, continue to expand, causing problems for native species. Increased monitoring is required to avoid further invasions; the recent emergence of the potentially invasive greater white-toothed shrew in north-east England highlights the current importance. Other species of high public interest, such as the badger, remain the focus of debates about their management despite limited information on their the abundance and distribution at a national scale.

In light of these concerns, MammalWeb (www.MammalWeb.org) was set up to encourage citizen scientists to engage in mammal monitoring by contributing camera trap images and associated metadata to a growing national database, and by helping with the task of classifying the resultant images [1]. In 2023, MammalWeb became part of the National Hedgehog Monitoring Programme (NHMP) run by the People’s Trust for Endangered Species and British Hedgehog Preservation Society [2]. The NHMP recruits groups and organisations concerned about the fate of the hedgehog to undertake distance-calibrated camera-trap surveys to allow for density estimation [3]. The first hedgehog density estimates for the 13 sites are now available, but the surveys have now expanded to incorporate over 40 sites with 3 million images sequences uploaded to MammalWeb. The dataset, coupled with MammalWeb’s other records, represents a fantastic opportunity to address a range of questions related to density, occupancy and ecology, not just for hedgehogs, but for the wide diversity of other British mammal species captured in the images. The student will have the opportunity to help refine the focus and may contribute to the dataset through running additional surveys in target habitats.

Thus, the aims of this project are:

1) to analyse classified data from the MammalWeb dataset to answer questions regarding the occupancy and activity of British mammals, as well as their natural and anthropogenic drivers;
2) to deploy arrays of camera traps to collect targeted data on specific habitats or British mammal species to calibrate, validate and improve inferences from citizen-led data collection; and,
3) to work with our CASE partner to showcase the use of ecological inferences to underpin future strategies for using camera traps and citizen science to understand the status of British mammals.

Methods will include deploying and calibrating camera traps following specific protocols to target under-represented species and habitats, with images uploaded to the MammalWeb platform [1] and tagged using both AI models and manual tagging. The project will use a range of statistical techniques to address the aims; occupancy [4-6], density [3,7-8] and activity [9] will be determined for various species using state-of-the-art analytical approaches. Training will be provided by all supervisors and partners and the student will have the opportunity to help shape the questions addressed and methods used.

Year 1

Learning techniques for camera trap use and analysis, including methods for occupancy, density and activity analyses. (including dedicated training)
Assessing potential for setting up camera trap surveys.
Evaluating pre-existing survey data.

Year 2

Guiding camera trap deployments.
Extracting data and conducting density, activity and occupancy analyses.
Placement with CASE partner.

Year 3

Initial analysis of data and drafting of results for publication; submission of first paper.
Commencing thesis write-up.

Year 3.5

Submission of papers.
Finalising thesis write-up.

Academic skills gained will include monitoring with camera traps, survey design, a range of cutting-edge techniques for analysing camera trap data, and scientific writing and communication.
Transferable skills and knowledge gained will include extensive experience of citizen science and outreach, as well as stakeholder engagement.