The Reintroduction of the lynx to Britain
Credit: Scotlandbigpicture.com
The Eurasian or northern lynx, Lynx lynx, is native to Britain. Previously thought to have become extinct in the Mesolithic as a result of climate change, radiocarbon dating of fossil remains shows it survived until at least the early Medieval period. Gaelic and Cumbric accounts suggest even longer persistence, though the exact dates are unknown. Its extinction was almost certainly a consequence of human activities including direct persecution, hunting, habitat loss and local extinction of prey species such as roe deer (Capreolus capreolus).
There is currently a legal imperative under the Habitats Directive to consider reintroductions of extinct species to EU states. In addition, proponents of ‘rewilding’, argue that the reintroduction of large animals that have become extinct since the last Ice Age is a key element in restoring ecosystems that are functional in the absence of human intervention.
Any reintroduction needs to be carefully planned, regardless of the species concerned, to maximise the likelihood of success and to reduce the risk of conflict with people and other wildlife. Guidelines for species reintroductions have been developed by the International Union for Conservation of Nature (IUCN), and in Scotland these guidelines have been built-on to produce The Scottish Code for Translocations. Mindful of these guidelines, the Mammal Society outlines below the steps that it believes must be taken to develop a responsible reintroduction strategy.
The likely causes of extinction must no longer be present. Lynx probably became extinct in Britain owing to lack of habitat and prey, and due to direct killing by humans. Reintroduction plans need to assess the likely impacts of plausible levels of persecution, prey availability and habitat suitability on population viability.
There should be sufficient habitat and prey to support self-sustaining populations. Research has established through modelling that the Highlands of Scotland could support a population of about 400 lynx, with a further 50 in the Southern Uplands. Formal estimates are not available for elsewhere but, based on habitat, it is likely that a similar number could be supported in England and Wales. However, the likely extent and timeframe of spread into the wider landscape needs to be assessed, with careful consideration being given to likely conditions outside the release areas.
The source population should be as similar as possible to the original native population. There are at least two lynx subspecies in Europe and molecular studies of British lynx are needed to establish their relationship with today’s extant populations. Any reintroduction should use appropriate source populations.
Lynx reintroductions should not threaten the conservation status of other extant native species. For example it has been suggested that lynx may kill Scottish wildcats, which are critically endangered in Britain. One radio-tracking study, which investigated 617 kills, found a single case of wildcat predation (Jobin et al. 2000). However it is also possible that the reintroduction of lynx may benefit Scottish wildcat conservation by reducing intra-guild completion with feral cats. This could happen if the more abundant feral cats are killed more frequently than wildcats, though we note that Jobin et al. (2000) recorded only a single case of domestic cat predation. Further assessment, informed by research studies on established populations elsewhere in Europe, is urgently required.
A long-term plan is needed for management of the future spread beyond re-introduction areas. This will need to include agreed aims and strategies for the conservation of, and — where needed — management of lynx populations in the wider landscape.
Appropriate risk assessment and mitigation options must be developed. These should identify the range of potential conflicts, outline effective mitigation and resolution options and include adaptive management plans if the reintroduction does not achieve the intended goals. The most likely conflicts are likely to result from the predation of sheep and domestic pets, particularly when lynx colonise areas outside the original reintroduction zone. It is possible for individual animals to habituate to using these animals as prey, creating localised problems. For example, in the French Jura, predation was spatially patchy, being concentrated within very small areas and involving just a few individual lynx (Stahl et al. 2001; Stahl et al. 2002). Most (68%) confirmed or probable killing incidents involved single sheep (18% involved two sheep) and attacks were mostly on lambs and sub-adults. A minority of flocks (10–23%) was attacked, and three-quarters of these were attacked once or twice a year. At the regional level, annual sheep losses to lynx were 0·14–0·59% of the total number of sheep. In some studies attack rates have been related to the population density of wild and/or and domestic prey, but the relationships are not straightforward and can either be positive, negative or neutral (Breitenmoser & Haller, 1993; Stahl et al. 2001; Gervasi et al. 2014), emphasising the importance of continuing monitoring and adaptive management post-release.
Mitigation options need to be practical if they are to be implemented successfully and include both quantification of the costs associated with mitigation actions and establishment of a funding mechanism to meet such costs. This could include compensation schemes, which can be effective in helping support reintroduction programmes but may be open to potential false or over-claiming. Other mitigations could include methods for minimising predation of livestock such selective removal of ‘problem’ lynx, or, if practical, overnight housing of stock or use of guard dogs.
Monitoring must be undertaken to assess the status of the populations and other wild animals before and after the reintroduction. For example, some deer populations may be locally diminished (particularly roe deer) because of direct predation and avoidance of areas where lynx are present. This has the potential to lead to recovery of over-browsed vegetation, and a reduction in damage to forestry and agriculture. However, it is also possible that there could be impacts on other predators, such as foxes, with unknown consequences for local ecosystems.
Stakeholder engagement is required at the outset and throughout any reintroduction programme to ensure the reintroduction is successful and sustainable. Public support for any reintroduction is essential, especially where the species is to be reintroduced. The reasons for reintroduction and the expected outcomes should be clear for all parties. Therefore extensive, and perhaps long-term, dialogue with all stakeholders is a necessity. Without clear support, especially amongst those likely to be in conflict with lynx, the prospect of success will be much lower.
The Mammal Society’s Position
The Mammal Society believes that the reintroduction of lynx to Britain is a viable proposition that conforms to the requirements of the Habitats Directive. Provided the factors described above are taken into consideration, the Society considers that restoration of this top predator could benefit the restoration and function of habitats and ecosystems in Britain. The aim of any such introduction should be a self-sustaining population that can be managed effectively in the event of conflicts, but which allows the lynx to become a functional part of British ecosystems.
References
Basille, M., Herfindal, I., Santin-Janin, H., Linnell, J. D., Odden, J., Andersen, R., Høgda, K. A., and Gaillard, J. M. (2009). What shapes Eurasian lynx distribution in human dominated landscapes: selecting prey or avoiding people? Ecography, 32: 683-691.
Bath, A. J., Olszanska, A., and Okarma, H. (2009). From a human dimensions perspective, the unknown large carnivore: Public attitudes toward Eurasian lynx in Poland. Human Dimensions of Wildlife, 13: 31-46.
Blake, D. (2009). The return of large carnivores to Britain – the hunters and the hunted. ECOS, 29: 25-32.
Bouyer, Y., Gervasi, V., Poncin, P., Beudels-Jamar, R. C., Odden, J., and Linnell, J. D. C. (2015). Tolerance to anthropogenic disturbance by a large carnivore: the case of Eurasian lynx in south-eastern Norway. Animal Conservation, 18: 271-278.
Breitenmoser, U., Haller, H. (1993). Patterns of predation by reintroduced European lynx in the Swiss Alps. The Journal of Wildlife Management. 1:135-144.
Gervasi V., Nilsen, E.B., Odden, J., Bouyer, Y., Linnell, J.D. (2014) The spatio‐temporal distribution of wild and domestic ungulates modulates lynx kill rates in a multi‐use landscape. Journal of Zoology. 292: 175-183.
Gray, J., Brockington, J., Hayward, M. and Walmsley (2016). How the proposed reintroduction of Eurasian lynx to Britain illustrates competing values and contrasting views associated with humans and the natural world. Country-Side. http://www.harmonywithnatureun.org/wordpress/wp-content/uploads/Papers/Lynx_reintroduction.pdf. Accessed 26/01/2018.
Hetherington DA, Lord TC, Jacobi RM. (2006). New evidence for the occurrence of Eurasian lynx (Lynx lynx) in medieval Britain. Journal of Quaternary Science. 21:3-8.
Hetherington, D. A. and Gorman, M. L. (2007). Using prey densities to estimate the potential size of reintroduced populations of Eurasian lynx. Biological Conservation 137: 37-44.
Hetherington, D. A., Lord, T. C., and Jacobi, R. M. (2006). New evidence for the occurrence of Eurasian lynx (Lynx lynx) in medieval Britain. Journal of Quaternary Science 21: 3-8.
Hetherington, D. A., Miller, D. R., MacLeod, C. D., and Gorman, M. L. (2008). A potential habitat network for the Eurasian Lynx Lynx lynx in Scotland. Mammal Review 38: 285-303.
Jobin, A., Molinari, P., and Breitenmoser, U. (2000). Prey spectrum, prey preference and consumption rates of Eurasian lynx in the Swiss Jura Mountains. Acta Theriologica. 45: 243-252
Kitchener, A.C. and Bonsall, C. (1997). AMS radiocarbon dates for some extinct Scottish mammals. Quaternary Newsletter no. 83: 1–11.
Kitchener AC (2001) Two tales of two kitties: Restoring the wildcat, Felis silvestris, and the lynx, Lynx lynx, to Britain. In: Bowen, C.P. (ed.). The return of the native – the reintroduction of native species back into their natural habitat, pp. 24–27. People’s Trust for Endangered Species /Mammal Trust UK: London.
Linnell, J.D., Breitenmoser, U., Breitenmoser-Würsten, C., Odden, J., and von Arx, M. (2009). Recovery of Eurasian lynx in Europe: What part has reintroduction played? In: Hayward, M.W and Somers, M. J. (eds.). The reintroduction of top-order predators, pp. 72-91. Oxford: Blackwell.
Milner, J.M. and Irvine, R.J. (2015). The potential for reintroduction of Eurasian lynx to Great Britain: A summary of the evidence. British Deer Society Commissioned Report.
Odden, J., Nilsen, E. B., and Linnell, J. D. C. (2013). Density of wild prey modulates lynx kill rates on free-ranging domestic sheep. PLoS ONE, 8: e79261.
Stahl, P., Vandel, J.M., Herrenschmidt, V. and Migot, P. (2001) Predation on livestock by an expanding reintroduced lynx population: long-term trend and spatial variability. Journal of Applied Ecology, 38: 674–687.
Stahl, P., Vandel, J.M., Ruette, S., Coat, L., Coat, Y., Balestra, L. (2002). Factors affecting lynx predation on sheep in the French Jura. Journal of Applied Ecology. 39:204-216.
Yalden, D.W. (1999). The history of British mammals. Poyser: London