Managing Introduced Species

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.


Dr Sarah Crowley (University of Exeter) 

Professor Robbie McDonald (University of Exeter) 

Professor Steve Hinchliffe (University of Exeter)