CR2025_33 The cat’s whiskers: novel isoscape techniques using vibrissae from wild cats to track climate change impacts

Lead Supervisor: Stuart Black, Department of Geography and Environmental Sciences, University of Reading

Email: s.black@reading.ac.uk

Co-supervisors: Andrew Kitchener, National Museums Scotland

Climate change is continuing to affect ecosystems from individual species to entire population communities. There is a substantial body of literature addressing these areas, however, it is still difficult to predict the ecological impact of climate change due to the nature of the evidence available. Part of the problem is not having a key marker for the variability within species, for example, geographical ranges, diet variability, environmental stress within populations. Modern ecological studies can address some of these, but what is missing is a time-depth perspective on how species have changed in response to climate change.

What is needed are species-specific, individual markers of climate change and direct measurable impacts on these species to indicate the response of individual animals and population groups to climate. This project will, for the first time, investigate long-term records of climate change as recorded IN animals, that can be used as both an independent record of climate and a record of how the animal species has been impacted. Uniquely, we will investigate multi-proxy climate, environment and diet change event records from animal tissues that faithfully record all of these in a climate and an animal-specific record.

Wild cats (Felis silvestris) have continuously depositing tissues (whiskers) that grow at constant rates, (0.4mm per day; Cecchetti et al., 2020). These tissues record faithfully imprints of diet, health, environment and climate, over a short time intervals, circa a 3 to 4-month period. Data can be obtained from the analysis of C, N and S isotopes (diet structure), O and H isotopes, (climate reconstruction/geographical location) and trace elements (environmental exposure/stress) in the whisker samples. In addition, The National Museums of Scotland (co-investigator) has an extensive (n=450) archive record of wildcat skins and skeletons that date back to the 19^th Century, each of which has a known collection location and death date, with whiskers available for analysis. Although each whisker represents circa 3-4 months, as a collective group, this archive has a near continuous record of climate, environmental exposure and diet habits of the cats on a daily/sub-daily basis recorded in the whiskers. In addition, the ability to collect large quantities of data from samples, quickly means we are now in a position to analyse these samples to obtain these unique records. This project, will therefore, have the opportunity to investigate a unique museum collection to answer a key question regarding biodiversity response to climate change.

In order to interpret the climate signals in the cat tissues, we will need to undertake two sets of experimental data: Firstly, we need to better understand element trophic enrichment (from diet) in cats. To do this we will analyse wildcat fur from captive wildcats at the Highland Wildlife Park (part of the Royal Zoological Society of Scotland (RZSS)). We already have permission to do this, which will involve keepers collecting fur from captive wild cats that has been naturally shed and taking samples of the diet elements fed to the wildcats. Once this is complete, we will be able to calculate the imprint of the C-N-S-O-H isotopes and elements from prey diet to wildcat.

Secondly, we will need to collate the records available from modern water analyses (rainfall and ground water) from SEPA alongside obtaining historical records. However, in order to correct the data for historical samples, we will use preserved plant specimens from the University of Reading Herbarium supplemented by sampling other herbaria as required (e.g. Edinburgh Botanic Gardens). Such specimens all include date and locality of collection and are stored as dried samples. As wild cats are not obligate drinkers, they will primarily derive climate signals from their prey which ultimately all consume plant material. Mapping the past plant community O-H isotopes will create a series of historical isotope maps (isoscapes; Figure 1), to which we will be able to statistically map the cats onto, once the trophic enrichment correction has been undertaken.  The maps will be produced in ArcGIS Model Builder (an example is given below in Figure 1). Finally, rigorous statistical analyses will be undertaken to assess the range and variability of the data alongside a series of population and genetic (data already collected) to understand the geographical and diet behaviour in response to environmental and climate variability.

Training opportunities:

Training in relevant laboratory techniques (isotopic and elemental analyses) and data analyses (stable isotopes and modelling in R, ArcGIS Model Builder and isoscape production; Black) will be given at Reading, in addition to handling and using herbarium collections (Culham). The student will spend a placement period at the National Museums of Scotland (Kitchener) where training for Royal Zoological Society of Scotland (RZSS) to work with museum collections, captive wildcats and historical materials will be undertaken. In addition, the RZSS will also help undertake fieldwork to observe wildcat behaviour. 

Student profile: 

This PhD will appeal to a range of disciplines and offers interdisciplinary training in environmental, analytical and biodiversity skills. Laboratory skills are desirable and knowledge, experience and interest in environmental science, biology, zoology, botany, and conservation biology would be advantageous. Students trained in the following areas would be appropriate: Ecology, Environmental Science, Biology, Geography Conservation, Zooarchaeology. For informal queries, please contact Dr Stuart Black (s.black@reading.ac.uk) 

Co-Sponsorship details: 

This project will receive a CASE award from National Museums of Scotland.

References:

• Cecchetti et al. (2020) Contributions of wild and provisioned foods to the diets of domestic cats that depredate wild animals. Ecosphere, 12(9), e03737. 10.1002/ecs2.3737
• Scheffers, B. R. et al. (2016). The broad footprint of climate change from genes to biomes to people. Science, 354(6313), 719.