Project Archive: Managing Introduced and Invasive Species

I: Individual Specialisation in Established Biological Invasions

rat_in_trap[2]Invasive species represent an increasing global issue with huge biological and economic costs and consequences. As a result, substantial attention and resources have been channelled into invasive species control; but there is always a need to refine and enhance techniques. One such step is to move from a focus on invasive populations to develop an understanding at the level of individual invaders. This will help to resolve underlying mechanisms and interactions, and determine the behavioural consequences of specific trait combinations within individuals. Understanding variation at the individual rather than the population level is increasingly seen as having important implications for species’ ecology, evolution and conservation, and can be utilised to inform and improve applied outcomes.

Research led by Dr Thomas Bodey uses a natural experiment across invaded islands in New Zealand to understand the extent, covariance and persistence of individual variation across multiple traits (dietary, behavioural and cognitive) in invasive rat species in the wild. Using approaches from behavioural and community ecology, comparative psychology, conservation and invasion biology, we are explicitly testing how the fundamental ecological processes of competition and predation modulate trait combinations and create context-dependence in the impacts of individuals. We are also examining the role of individual phenotypes in affecting the extent to which they alter individual invaders’ impacts on native biota and their potential to interact with control mechanisms in order to improve conservation management actions addressing a global problem.

Research Team

Dr Thomas Bodey (Marie Skłodowska-Curie Global Research Fellow)

Professor Robbie McDonald (University of Exeter)

Dr James Russell (University of Auckland)

II: Ecological Politics and Practices in Invasive Species Management

The surveillance and control of introduced species has become an increasingly important, yet often controversial, form of environmental management. Dr Sarah Crowley’s PhD research examined the causes and consequences of social conflicts in introduced species management, and investigated how introduced wildlife is managed in the United Kingdom through a series of case studies.


Monk Parakeets. Photo: Luis García.

Introduced monk parakeets (Myiopsitta monachus) have been subject to a government initiated eradication programme since 2011. By asking how and why self-labelled ‘Parakeet Protectors’ opposed this initiative, we identified the importance of (a) the different ways people evaluate the risks posed by wildlife introductions; (b) personal and community attachments that develop through interactions between people and parakeets; and (c) campaigners’ dissatisfaction with central government’s approach to the issue. Building on this case study, we developed a framework for incorporating social impact assessments into introduced species management, a process which may help minimise the likelihood of destructive conflicts in future.

Using a multi-sited study of grey squirrel (Sciurus carolinensis) control projects and activities, we found important variations in management practitioners’ approaches to killing squirrels, and identify several ‘modes of killing’ that are made up of different primary motivations, moral principles, ultimate aims, and practical methods. We identify key areas of both potential collaboration, and possible tension, between the different ‘arms’ of grey squirrel control.

Beaver Release

Eurasian beavers were re-released onto the River Otter in 2016, following a health check and a public dispute about their future. Photo: Nick Upton.

This project also used the re-introduction of formerly resident Eurasian beavers (Castor fiber) to the United Kingdom as a comparative study.  By following the story of the unauthorised escape/release of beavers to Devon, we identified how a diverse collective of people were temporarily united and empowered by a shared understanding of beavers as ‘belonging’ in the UK. We demonstrate that ‘nonhuman citizenship’ is not given, but socio-politically negotiated, and suggest that beavers have now become part of an important social and ecological experiment in environmental management.


Crowley, S. L., Hinchliffe, S., & McDonald, R. A. (2017). Conflict in invasive species management. Frontiers in Ecology and the Environment15(3), 133-141.

Crowley, S. L., Hinchliffe, S., & McDonald, R. A. (2017). Invasive species management will benefit from social impact assessment. Journal of Applied Ecology54(2), 351-357.

Crowley, S. L., Hinchliffe, S., Redpath, S. M., & McDonald, R. A. (2017). Disagreement about invasive species does not equate to denialism: A response to Russell and Blackburn. Trends in ecology & evolution32(4), 228-229.

Crowley, S. L., Hinchliffe, S., & McDonald, R. A. (2017). Nonhuman citizens on trial: The ecological politics of a beaver reintroduction. Environment and Planning A49(8), 1846-1866.

Crowley, S. L., Hinchliffe, S., & McDonald, R. A. (2018). The Parakeet Protectors: understanding opposition to introduced species management. Journal of environmental management.

Crowley, S. L., Hinchliffe, S., & McDonald, R. A. (2018). Killing squirrels: Exploring motivations and practices of lethal wildlife management. Environment and Planning E: Nature and Space, 2514848617747831.

Research Team

Dr Sarah Crowley (University of Exeter) 

Professor Robbie McDonald (University of Exeter) 

Professor Steve Hinchliffe (University of Exeter)