Chris D Thomas

Contact details

Type of addressPostal address
Postal codeYO10 5DD
CountryUnited Kingdom
Address lines
  • Biology
    University of York
    Wentworth Way
    YO10 5DD

Phone: (01904) 328646

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Prof. Chris D Thomas, FRS


Area of expertise

  • Climate change impacts in ecology
  • Conservation
  • Butterfly ecology
  • Biodiversity

PhD opportunities

Available PhD research projects

1. The accumulation of regional diversity in the Anthropocene: insects on plants. A paradox in ecology is that the number of species is increasing in many countries across the world, despite the fact that the total number of species on Earth is declining. The increase is being generated as a result of many species establishing in new regions, where they predominantly occupy novel environments created by human activities; and hence they can live in the region without displacing native species. Far less is known about the ecological and evolutionary ‘rules’ that govern this accumulation of species in novel environments than about the causes and patterns of extinction of species.

This PhD project will tackle the issue of diversity gains. This is essential because all biological communities are in flux across the world as a result of many human-caused changes to the environment. Any management decisions need to consider gains as well as losses of species, whereas the current emphasis is almost exclusively on losses. The project will use insects on introduced plants as the ‘model’ system, where each introduced plant can be thought of as a replicated novel environment (that would not exist in the region if people had not introduced them).

The project will examine what factors determine how many and which insect species are associated with each introduced plant. The project provides considerable scope, involving analysis of existing data bases, practical field work, and development of a new citizen science project; enabling the student to develop skills spanning several areas of modern ecology. It will suit people with good statistical skills, a fondness of the outdoors, and excellent communication skills. The project will be co-supervised by Chris Thomas at the University of York, where the student will be registered and primarily based, David Roy at the NERC Centre for Ecology and Hydrology, and Andy Salisbury at the Royal Horticultural Society.

Potential self/overseas funded projects.

2. The effects of non-native species on biodiversity patterns. Non-native species are widely regarded as threats to native biodiversity at local, regional and global scales, and invasive species have been responsible for a third or more of documented species-level extinctions. Nonetheless, the net effect of non-native species is usually to increase regional diversity – fewer than one native species dies out, on average, for each new species that is added. The circumstances that lead to net losses and gains are poorly understood. The studentship will test how non-native species affect local diversity (alpha), differences in diversity between locations (beta diversity) and the total numbers of species in regions and globally (gamma diversity), using historical (palaeo-ecological) and recent data (e.g. Countryside Survey plots). The student will compare results for plants and vertebrates. The project will test the generality of the results by comparing the conclusions for Britain against data for at least two other regions of the world.

3. The accumulation of species in novel Anthropocene habitats. The project will examine the diversity of species associated with new habitat types that have been created by humans. The student will develop a model for species accumulation, dependent on the isolation of derived habitats from potential sources of colonists and the time over which the derived habitat has been available for colonisation. The model will be tested by comparing the predicted patterns of diversity with those observed, using a combination of existing data sources and new data collected by the student.