Imagine your future holiday. You wouldn’t plan on walking through a degraded landscape or want a constant fear of disease ruining your trip, would you? Due to a rapid increase in red deer populations (Cervus elaphus), this becoming a harsh reality facing holidaymakers in Scotland. In the past deer were seen as a tourism highlight, however social, economic and environmental consequences of deer overabundance mean efficient and cost effective management strategies are required. Katie moved away from traditional methods and addressed the use of Apex predators as an option for controlling deer populations in Scotland.
Picture a landscape without any deer. This was the case in the 1700s, when red deer were extinct in the Scottish lowlands. Fast forward to present day and this is hard to imagine as the species has seen a significant increase (75-80% since the 1960s), predominantly due to an increase in demand for deerstalking. Now overabundance is producing major ecological consequences, such as directly selective grazing which has altered and degraded plant communities. Higher deer densities have resulted in overgrazing, which have reduced forest regeneration and indirectly produced cascading effects on animal communities influencing bird densities2. From an economic perspective, grazing pressure has produced competition with livestock, in particular highland sheep farming, which has reduced income to the agricultural sector2. Human-deer conflicts continue as human health is directly affected by increased deer abundance, including a rise in road accidents3. Deer act a natural reservoir for diseases including lyme disease. Lyme disease is spread through ticks; if you get bitten by an infected tick it could prove fatal if left untreated4. Habitat monitoring has been used to assess the impacts of deer on ecosystems and as a tool for guiding management decisions.
Currently, deer populations are being actively managed through traditional strategies, however these are proving inefficient. Methods include culling: where a certain proportion of the population are shot5. This strategy requires a lot of manpower and is only successful when a certain amount of deer are killed5. The financial costs of hiring deer stalkers and shooting quality deer, disparity between neighbouring estates and migration of deer prove that this is not an effective management strategy5. Another widely used approach is trapping and relocating deer from high density areas to low density areas. In the past the movement of fallow deer (Dama dama), have increased incidences of car accidents6. Coupled with concerns over animal welfare, with this method proving highly stressful to deer and again the financial burden6, this method proves inefficient. Finally, fencing off areas such as woodland areas produce visual vegetative regeneration. The building and maintenance of fences can cost as high as £7.8 million and restricts other species movement.
Current and past well known deer management techniques have proved inefficient. Regeneration of ecosystems will require controlling deer populations in a time and cost efficient sustainable way. You may not know that the use of Apex predators as a method for deer management is being considered as an option for controlling deer within Scotland. Once abundant in Scotland natural predators of deer including wolves (Canis lupus) which were eradicated by 1769 and lynx (Lynx lynx) over 13,000 years ago. Apex predators reduce populations to a sustainable level whilst providing other ecosystem benefits 7.
They can be described as a keystone species – meaning they directly affect trophic food webs, biodiversity and ecosystem functioning8. Success stories have occurred where wildlife researchers have reintroduced native predators including the classic example from Yellowstone National Park. Wolf reintroduction effectively reduced elk numbers whilst producing a trophic cascade. Reduced grazing pressure increased both animal and plant communities, producing a more diverse ecosystem8.
While this may seem like a feasible option, it has faced large opposition with the majority of that coming from residents and workers in the regions where the reintroductions are proposed. Estate land owners and managers are concerned that a reduction in deer populations would reduce the number of high quality deer, impairing the shooting industry and reducing estate income2. Conservationists are concerned that reintroduction would put native species at risk including the Scottish wildcat (Felis silvestris silvestris) through niche overlap 9. Finally, farmers are faced with reduced income, through threats of livestock attacks, in particular sheep herds10. By working with local estate managers, farmers and conservationist’s decision makers can overcome these issues and produce minimum impact of apex predator reintroduction.
Deer densities within Scotland have now reached an unsustainable level but populations continue to grow. Large abundances cause many damaging effects socially, economically and environmentally. Current methods being used to control deer populations are proving inefficient. Apex predators provide a natural way of controlling populations whilst providing other benefits to the ecosystems. Though the strategy has had a lot of backlash from local residents and conservation authorities it is the only sustainable, cost effective and effective way which can stop rapid deer population growth.
So what do you think? Are reintroductions of apex predators to Scottish ecosystems for the purpose of deer management a good idea?
The British deer society support a wide range of scientific research into deer habitat and welfare. If you’re interested they provide training and education surrounding effective deer management.
Scottish Wildlife WATCH, run by the Scottish Wildlife Trust, produces a magazine and Scottish newsletter which include information about environmental issues and give you the chance to help wildlife by taking part in projects and surveys.
- Contact: Scottish Wildlife WATCH, Cramond House, Cramond Glebe Road, Edinburgh EH4 6NS
So what are you waiting for? Get involved today!
1Aebischer, N. J., Davey, P. D., & Kingdon, N. G. (2011). National Gamebag Census: Mammal Trends to 2009. Game & Wildlife Conservation Trust, Fordingbridge.
2 Nilsen, E. B., Milner-Gulland, E. J., Schofield, L., Mysterud, A., Stenseth, N. C., & Coulson, T. (2007). Wolf reintroduction to Scotland: public attitudes and consequences for red deer management. Proceedings of the Royal Society of London B: Biological Sciences, 274(1612), 995-1003.
3Ostfeld, R. S., Canham, C. D., Oggenfuss, K., Winchcombe, R. J., & Keesing, F. (2006). Climate, deer, rodents, and acorns as determinants of variation in Lyme-disease risk. PLoS Biol, 4(6), e145.
4Nilsen, E. B., Milner-Gulland, E. J., Schofield, L., Mysterud, A., Stenseth, N. C., & Coulson, T. (2007). Wolf reintroduction to Scotland: public attitudes and consequences for red deer management. Proceedings of the Royal Society of London B: Biological Sciences, 274(1612), 995-1003.
5Clutton-Brock, T. H., & Lonergan, M. E. (1994). Culling regimes and sex ratio biases in Highland red deer. Journal of Applied Ecology, 521-527.
6Ramirez, S. 2016. Deer Management Strategies. PLSC 480: Management of Urban Forest Edges.
7Moore, O., & Crawley, M. J. (2014). Red deer exclusion and saxicolous cryptogam community structure. The Lichenologist, 46(02), 229-244.
Arts, K., Fischer, A. and van der Wal, R. 2015. Boundaries of the wolf and the wild: a conceptual examination of the relationship between rewilding and animal reintroduction. Restoration Ecology 24:27-34
8Letnic, M., Ritchie, E.G. and Dickman, C.R. 2012. Top predators as biodiversity regulators: the dingo Canis lupis dingo as a case study. Biological Reviews 87:390-413
9Lorimer, J., Sandom, C., Jepson, P., Doughty, C., Barua, M., & Kirby, K. J. (2015). Rewilding: Science, practice, and politics. Annual Review of Environment and Resources, 40, 39-62.
10Ritchie, E.G., Elmhagen, B., Glen, A.S., Letnic, M., Ludwig, G. amd McDonald, R.A. 2012. Ecosystem restoration with teeth: what role for predators? Trends in Ecology and Evolution 27:265-271