Evaluating the potential consequences of climate heating for Caspian seals and ecosystem services in the Caspian Sea

Summary

The School of Biology invites applications from prospective postgraduate researchers who wish to commence study for a PhD in the academic year 2024/25.

This project aims to under how marine mammals will respond and adapt to climate change. We will use Caspian seals as a system to help us understand conservation threats to the species, and potential responses of ice breeding seals in other parts of the world. Evaluating how pinnipeds will respond to climate change is a priority for understanding the future structure, function and stability of marine ecosystems, given their role as top predators.

We will use existing satellite telemetry data for Caspian seals, combined with a range of ecological modelling approaches to understand habitat use and behaviour in relation to environmental variables, and how this may respond to changes in winter ice and high summer sea surface temperatures. We will also carry out risk assessments for how changing environmental conditions will impact Caspian seal habitat, and the consequences for other Caspian Sea biodiversity. We expect the work to be relevant to informing climate change response policy for the Caspian Sea region.

Marine mammals are keystone species for marine ecosystems. Understanding how they could be impacted by climate heating is important for evaluating risks to marine biodiversity, ecosystem function and ecosystem services. The Caspian seal (Pusa caspica), is endemic to the Caspian Sea in Central Asia, the largest landlocked waterbody on the planet. Recent global risk assessments suggest the Caspian seal may have the greatest vulnerability to climate heating of any marine mammal species, due to loss of its sea ice breeding habitat and decline of the Caspian Sea level. However, an in depth assessment of potential threats and impacts of climate heating on Caspian seals based on detailed knowledge of species ecology and biology remains to be conducted. Such an assessment is not only critical for informing conservation strategy for Caspian seals, but will also berelevant to wider understanding of risks to biodiversity, ecosystem services and for human populations of the Caspian Sea region more generally.

In this project we will use an existing satellite telemetry dataset (Dmitrieva et al. 2016) from more than 100 tags deployed between 2009 and 2018 to describe Caspian seal activity budgets (time investment in foraging/diving and resting activity) in relation to environmental drivers, and evaluate the effects of high sea surface temperatures on seal behaviour, and how this relates to risks for thermal stress in the summer months. We will also evaluate the impact of Caspian sea level decline (predicted to be up to 18m by 2100), on the availability of Caspian seal breeding habitat and how this may influence whether Caspian seals could adapt to terrestrial breeding. Additionally we will develop risk assessments for the habitats of other key Caspian species including fish, benthic fauna and birds. Finally we will use the Marxan package to identify spatial planning solutions for seal marine protected areas under current conditions and human activity, and future sea level decline scenarios.

Ultimately the project could act as template for climate impact risk assessments for marine mammals more generally, and will provide important policy relevant information on managing Caspian Sea biodiversity during the coming Century.

The student will receive training in marine mammal ecology and conservation, analysis of satellite telemetry datasets, spatial statistical modelling, and spatial conservation planning and prioritisation analyses. The project will be primarily focused on analysing existing datasets, but some participation in fieldwork may be possible.

The project would suit students with an interest in marine mammal conservation and spatial statistical modelling. Evidence of strong quantitative skills is desirable, or of aptitude to develop proficiency in this area.

References

• Albouy, C., Delattre, V., Donati, G. et al. Global vulnerability of marine mammals to global warming. Sci Rep 10, 548 (2020). https://doi.org/10.1038/s41598-019-57280-3
• Dmitrieva, L., Jüssi, M., Jüssi, I., Kasymbekov, Y., Verevkin, M., Baimukanov, M., Wilson, S., & Goodman, S. J. (2016) Individual variation in seasonal movements and foraging strategies of a land-locked, ice-breeding pinniped. Marine Ecology Progress Series, 554:241-256. doi: 10.3354/meps11804.
• Prange, M., Wilke, T. & Wesselingh, F.P. The other side of sea level change. Commun Earth Environ 1, 69 (2020). https://doi.org/10.1038/s43247-020-00075-6
• Wilson, S. C., Dolgova, E., Trukhanova, I., Dmitrieva, L., Crawford, I., Baimukanov, M., Goodman, S. J. (2017). Breeding behavior and pup development of the Caspian seal, Pusa caspica. Journal of Mammalogy, 98(1):143–153, doi: 10.1093/jmammal/gyw176.

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