Summary
In this perspective article, the author identifies three wild animals which are considered pests in Europe: the red fox, crow, and Eurasian badger. The author highlights the attempted population control of these three animals and why they have been unsuccessful. With COVID-19 bringing to light how diseases can be transmitted through human exploitation of wildlife, conservation and sustainable development needs to consider possible diseases. Current strategies for removing “pests” focus on reducing the population of the species, which could threaten biodiversity if, for example, organizations adopt this approach to manage wildlife with the potential to transmit diseases to humans.
The red fox is considered a pest in Europe as they cause damage to crops and can carry rabies and echinococcosis. Consequently, in France, hunters kill 500,000 foxes annually; however, studies conducted in the UK and France show hunting to have no effect on the fox population and to increase the prevalence of echinococcosis. Similarly, 1,150,000 crows are killed annually in Europe. Research provides evidence that crows engage in a “fusion-fission group dynamic”, meaning individuals do not stay in one group but rather come together where there is food and disperse, with very large home ranges (up to 40,000 km²) making local control ineffective. Crows can carry avian flu, West Nile virus, and Usutu flavivirus which needs to be considered when implementing a control strategy. Finally the Eurasian badger is a carrier and transmitter of bovine tuberculosis (TB), which is the most urgent cattle health problem in Europe. A study conducted in the UK in the mid 1980’s saw that badger culling increased TB by 27% when compared to herds in areas with no culling.
The author gives suggestions on how to go about “pest” control, firstly by assessing how much damage the animal has or can do, secondly researching how the population behaves, thirdly evaluating the economic cost, and lastly to determine if the population control succeeded in reducing damage or disease. In summary, the current “pest” control strategies are unsuccessful, are damaging human-wildlife relationships, and need to be reevaluated.
The recent discovery that cats and mustelids can be infected by SARS-CoV-2 may raise the question of monitoring domestic, feral and wild populations of such animals, as an adjunct to the elimination of COVID-19 in humans. Emergency solutions might consider large scale control of these animals in the wild. However, looking at science recently published on native vertebrate pest control reveals first that usual controls do not succeed in reducing animal numbers and associated damages, second that controlling can be counter-productive in increasing the infectious risks for humans and livestock. The examples of red fox and corvids are detailed in a European context, illustrating the urgent need for an ethical evaluation of ecological and economic costs and benefits of pest control strategies. A complete scientific evaluation process must be implemented and up-dated regularly, to be organized in four major steps, once the aim of the control strategy has been defined: (1) evaluating damages/risks caused by the animals, to be balanced with the ecosystem services they may provide, also in terms of economic costs; (2) unravelling spatial and temporal population dynamics of target animals to identify, if any, optimal control scenarios – which could be done within an adaptive management framework; (3) estimating the economic costs of implementing those optimal control scenarios, to be compared to the economic costs of damages/diseases; (4) finally evaluating how the control strategy reached its aims. A modern fable of the Fox and the Crow should deliver a timely moral for an ethical, ecological and economical appraisal of pest control strategies in Europe.