Free Standard AU & NZ Shipping For All Book Orders Over $80!
Register      Login
Wildlife Research Wildlife Research Society
Ecology, management and conservation in natural and modified habitats
Shopping Cart: ( empty )
You are here: Home > Journals > WR > WR22194
RESEARCH ARTICLE (Open Access)
Contents Vol 51(1)

Modelling the management of an invasive species at landscape scale: are oral contraceptives the missing ingredient for success?

S. Croft https://orcid.org/0000-0002-8653-944X A * and G. Massei https://orcid.org/0000-0001-6050-2174 B
+ Author Affiliations
- Author Affiliations

A National Wildlife Management Centre, Animal and Plant Health Agency, York, UK.

B Botstiber Institute for Wildlife Fertility Control Europe, Department of Environment and Geography, University of York, York, UK.

* Correspondence to: simon.croft@apha.gov.uk

Handling Editor: Douglas Eckery

Wildlife Research 51, WR22194 https://doi.org/10.1071/WR22194
Submitted: 6 December 2022  Accepted: 18 August 2023  Published: 12 September 2023

© 2024 The Author(s) (or their employer(s)). Published by CSIRO Publishing. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND)

Abstract

Context

Invasive non-native species are on the rise worldwide, exacerbating already significant environmental and economic impacts. Concurrently, public attitudes towards methods of controlling these species are changing, with greater demand for non-lethal solutions. This has fostered research into developing new, effective technologies and strategies for wildlife management.

Aims

On the basis of a case study focusing on the eastern grey squirrel (Sciurus carolinensis) in the UK, this study aimed to understand the potential for population management, using either live trapping or oral contraception. First, assuming completely coordinated landscape-scale control, and then, coordinated control only on parts of the landscape, accounting for the potential that landowners’ attitudes towards alternative methods may differ and reflect those of the wider public.

Methods

We used an existing spatially explicit individual-based modelling approach applying various parameterisations to define management. We varied the density of traps or hoppers delivering contraceptives, the duration of deployment, contraceptive efficacy, initial population size, and the probability of landowner participation. The latter was based on a previous public survey, suggesting that 40% of the respondents were open to management using trapping and 64% to using contraception.

Key results

With complete coordinated control, trapping was generally faster and more cost-effective than was contraception. However, when differences in social acceptance were considered, reducing participation and, consequently, the spatial coverage of management, contraception was found to maintain greater population reductions than was trapping with similar effort, assuming a contraceptive efficacy of 75% or higher.

Conclusions

This study added another layer of complexity to managing invasive non-native species, namely the potential effect that landowners’ attitudes to different methods of population management might have on the level of coordinated control at landscape scale. In a situation such as the one modelled by this study, where management is not a legal requirement, this human dimension must be considered alongside cost-effectiveness, to develop successful control in line with management goals.

Implications

Further work is required to establish the actual attitudes of landowners, and in different contexts (e.g. urban, rural areas), how this may change as new approaches become available, and then how spatial variation (clustering) in the resulting wildlife population control may affect outcomes.

Keywords: comparison, contraception, cost, human dimension, individual-based model, invasive non-native species, population management, social acceptance, spatial coverage, trapping.

References

Beatham SE, Goodwin D, Coats J, Stephens PA, Massei G (2021) A PIT-tag-based method for measuring individual bait uptake in small mammals. Ecological Solutions and Evidence 2(2), e12081.
| Crossref | Google Scholar |

Bertolino S, di Montezemolo NC, Preatoni DG, Wauters LA, Martinoli A (2014) A grey future for Europe: Sciurus carolinensis is replacing native red squirrels in Italy. Biological Invasions 16(1), 53-62.
| Crossref | Google Scholar |

Bertolino S, Lurz PW, Shuttleworth CM, Martinoli A, Wauters LA (2016) The management of grey squirrel populations in Europe: evolving best practice. In ‘The grey squirrel: ecology & management of an invasive species in Europe’. (Eds C Shuttleworth, P Lurz, J Gurnell) pp. 495–516. (European Squirrel Initiative: Stoneleigh Park, Warwickshire, UK)

Bremner A, Park K (2007) Public attitudes to the management of invasive non-native species in Scotland. Biological Conservation 139(3–4), 306-314.
| Crossref | Google Scholar |

Chen X, Hou X, Feng T, Han N, Wang J, Chang G (2022) Anti-fertility effect of levonorgestrel and/or quinestrol on striped field mouse (Apodemus agrarius): evidence from both laboratory and field experiments. Integrative Zoology 17, 1041-1052.
| Crossref | Google Scholar | PubMed |

Croft S, Chauvenet ALM, Smith GC (2017) A systematic approach to estimate the distribution and total abundance of British mammals. PLoS ONE 12(6), e0176339.
| Crossref | Google Scholar | PubMed |

Croft S, Aegerter JN, Beatham S, Coats J, Massei G (2021) A spatially explicit population model to compare management using culling and fertility control to reduce numbers of grey squirrels. Ecological Modelling 440, 109386.
| Crossref | Google Scholar |

Crowley SL, Hinchliffe S, McDonald RA (2018) Killing squirrels: exploring motivations and practices of lethal wildlife management. Environment and Planning E: Nature and Space 1(1–2), 120-143.
| Crossref | Google Scholar |

Derbridge JJ, Pepper H, Koprowski J (2016) Economic damage by invasive grey squirrels in Europe. In: ‘The grey squirrel: ecology & management of an invasive species in Europe’. (Eds C Shuttleworth, P Lurz, J Gurnell) pp. 393–405. (European Squirrel Initiative: Stoneleigh Park, Warwickshire, UK)

Dunn M, Marzano M, Forster J, Gill RMA (2018) Public attitudes towards ‘pest’ management: perceptions on squirrel management strategies in the UK. Biological Conservation 222, 52-63.
| Crossref | Google Scholar |

Genovesi P, Bertolino S (2001) Human dimension aspects in invasive alien species issues: the case of the failure of the grey squirrel eradication project in Italy. In ‘The great reshuffling: human dimensions of invasive alien species’. (Ed. JA McNeely) pp. 112–119. (IUCN Publications Services Unit: Cambridge, UK)

Gill R, Massei G, Pinkham R, Beatham S, Whitelaw B, McNicol C (2022) Grey squirrel control research – what new approaches may we anticipate for the future? Quarterly Journal of Forestry 116, 54-61.
| Google Scholar |

Goldstein EA, Butler F, Lawton C (2016) Modeling future range expansion and management strategies for an invasive squirrel species. Biological Invasions 18(5), 1431-1450.
| Crossref | Google Scholar |

Gurnell J (1999) Grey squirrels in woodlands: managing grey squirrels to prevent woodland damage. Enact 7, 10-14.
| Google Scholar |

Gurnell J, Lurz PWW, Shirley MDF, Cartmel S, Garson PJ, Magris L, Steele J (2004) Monitoring red squirrels Sciurus vulgaris and grey squirrels Sciurus carolinensis in Britain. Mammal Review 34, 51-74.
| Crossref | Google Scholar |

Gurnell J, Pepper H (2016) The control and management of grey squirrel populations in Britain. In ‘The grey squirrel: ecology & management of an invasive species in Europe’. (Eds C Shuttleworth, P Lurz, J Gurnell) pp. 407–436. (European Squirrel Initiative: Stoneleigh Park, Warwickshire, UK)

HM Government (2021) ‘Net zero strategy: build back greener.’ (Department for Business, Energy, and Industrial Strategy (BEIS): UK)

Hunold C, Mazuchowski M (2020) Human–wildlife coexistence in urban wildlife management: insights from nonlethal predator management and rodenticide bans. Animals 10(11), 1983.
| Crossref | Google Scholar | PubMed |

Jacoblinnert K, Jacob J, Zhang Z, Hinds LA (2022) The status of fertility control for rodents – recent achievements and future directions. Integrative Zoology 17, 964-980.
| Crossref | Google Scholar | PubMed |

Krause SK, Kelt DA, Van Vuren DH, Gionfriddo JP (2014) Regulation of tree squirrel populations with immunocontraception: a fox squirrel example. Human–Wildlife Interactions 8(2), 168-179.
| Google Scholar |

La Morgia V, Paoloni D, Genovesi P (2017) Eradicating the grey squirrel Sciurus carolinensis from urban areas: an innovative decision-making approach based on lessons learnt in Italy. Pest Management Science 73, 354-363.
| Crossref | Google Scholar | PubMed |

Lioy S, Marsan A, Balduzzi A, Wauters LA, Martinoli A, Bertolino S (2019) The management of the introduced grey squirrel seen through the eyes of the media. Biological Invasions 21(12), 3723-3733.
| Crossref | Google Scholar |

Liu M, Ren D, Wan X, Shen X, Zhao C, Xingan Wang Y, Bu F, Liu W, Zhang Z, Gao Y, Si X, Bai D, Yuan S, Zheng F, Wan X, Fu H, Wu X, Zheng A, Liu Q, Zhang Z (2023) Synergistic effects of EP-1 and ivermectin mixture (iEP-1) to control rodents and their ectoparasites. Pest Management Science 79(2), 607-615.
| Crossref | Google Scholar | PubMed |

Locke CM, Anhalt-Depies CM, Frett S, Stenglein JL, Cameron S, Malleshappa V, Peltier T, Zuckerberg B, Townsend PA (2019) Managing a large citizen science project to monitor wildlife. Wildlife Society Bulletin 43(1), 4-10.
| Crossref | Google Scholar |

Lurz PWW, Rushton SP, Wauters LA, Bertolino S, Currado I, Mazzoglio P, Shirley MDF (2001) Predicting grey squirrel expansion in North Italy: a spatially explicit modelling approach. Landscape Ecology 16, 407-420.
| Crossref | Google Scholar |

Martinoli A, Bertolino S, Preatoni DG, Balduzzi A, Marsan A, Genovesi P, Tosi G, Wauters LA (2010) Headcount 2010: the multiplication of the grey squirrel introduced in Italy. Hystrix 21(2), 127-136.
| Google Scholar |

Massei G, Cowan D (2014) Fertility control to mitigate human–wildlife conflicts: a review. Wildlife Research 41, 1-21.
| Crossref | Google Scholar |

Massei G, Cowan D, Eckery D, Mauldin R, Gomm M, Rochaix P, Hill F, Pinkham R, Miller LA (2020) Effect of vaccination with a novel GnRH-based immunocontraceptive on immune responses and fertility in rats. Heliyon 6, e03781.
| Crossref | Google Scholar | PubMed |

Mathews F, Kubasiewicz LM, Gurnell J, Harrower CA, McDonald RA, Shore RF (2018) A review of the population and conservation status of British mammals. A report by the Mammal Society under contract to Natural England, Natural Resources Wales, and Scottish Natural Heritage. Natural England, Peterborough, UK.

Mayle B, Ferryman M, Pepper H (2007) Controlling grey squirrel damage to woodlands. Forestry Commission Practice Note 4. Forestry Commission, Edinburgh, UK.

Morzillo AT, Mertig AG (2011) Urban resident attitudes toward rodents, rodent control products, and environmental effects. Urban Ecosystems 14, 243-260.
| Crossref | Google Scholar |

Quinn N, Kenmuir S, Krueger L (2019) A California without rodenticides: challenges for commensal rodent management in the future. Human–Wildlife Interactions 13, 212-225.
| Google Scholar |

Richardson W, Jones G, Glynn M, Watson P (2021) An analysis of the cost of grey squirrel damage to woodland. Royal Forestry Society, UK.

Rushton SP, Lurz PWW, Fuller R, Garson PJ (1997) Modelling the distribution of the red and grey squirrel at the landscape scale: a combined GIS and population dynamics approach. Journal of Applied Ecology 34, 1137-1154.
| Crossref | Google Scholar |

Rushton SP, Lurz PWW, Gurnell J, Fuller R (2000) Modelling the spatial dynamics of parapoxvirus disease in red and grey squirrels: a possible cause of the decline in the red squirrel in the UK? Journal of Applied Ecology 37, 997-1012.
| Crossref | Google Scholar |

Rushton SP, Gurnell J, Lurz PWW, Fuller RM (2002) Modeling impacts and costs of gray squirrel control regimes on the viability of red squirrel populations. The Journal of Wildlife Management 66, 683-697.
| Crossref | Google Scholar |

Scapin P, Ulbano M, Ruggiero C, Balduzzi A, Marsan A, Ferrari N, Bertolino S (2019) Surgical sterilization of male and female grey squirrels (Sciurus carolinensis) of an urban population introduced in Italy. Journal of Veterinary Medical Science 81, 641-645.
| Crossref | Google Scholar |

Schuchert P, Shuttleworth CM, McInnes CJ, Everest DJ, Rushton SP (2014) Landscape scale impacts of culling upon a European grey squirrel population: can trapping reduce population size and decrease the threat of squirrelpox virus infection for the native red squirrel? Biological Invasions 16, 2381-2391.
| Crossref | Google Scholar |

Shi D, Wan X, Davis SA, Pech RP, Zhang Z (2002) Simulation of lethal control and fertility control in a demographic model for Brandt’s vole Microtus brandti. Journal of Applied Ecology 39, 337-348.
| Crossref | Google Scholar |

Shuttleworth CM, Robinson N, Halliwell EC, Clews-Roberts R, Peek H, Podgornik G, Stinson M, Rice S, Finlay C, McKinney C, Everest DJ (2020) Evolving grey squirrel management techniques in Europe. Management of Biological Invasions 11(4), 747.
| Crossref | Google Scholar |

Tattoni C, Preatoni DG, Lurz PWW, Rushton SP, Tosi G, Bertolino S, Martinoli A, Wauters LA (2006) Modelling the expansion of a grey squirrel population: implications for squirrel control. Biological Invasions 8(8), 1605-1619.
| Crossref | Google Scholar |

Wauters LA, Gurnell J, Currado I, Mazzoglio PJ (1997) Grey squirrel Sciurus carolinensis management in Italy – squirrel distribution in a highly fragmented landscape. Wildlife Biology 3(2), 117-124.
| Crossref | Google Scholar |