Sunday, 4 May 2014

Reintroducing large carnivores to Britain, could it happen ?

Hello and welcome to my latest blog. There was once a time where elk and ox roamed Britain's woodlands alongside deer and wild boar, while wolves, lynx and bears made up a formidable trio of predators ready to predate upon those caught off guard. Nowadays however, the woodlands are very different, long gone are the large predators along with the elk and ox on which they would have predated upon. Beavers and wild boar have repopulated the latter with a great deal of controversy attached. In the absence of large carnivores, deer populations have flourished to the point in which Britain's forests have suffered badly,with some areas destroyed never to recover. And so this poses the question, could Britain support large carnivores once more? or since their disappearance have to many changes occurred for this ever to be a possibility ? This blog focuses on the cases of wolves and lynx's as bears literature suggests  are the least likely to make a recovery, time has changed the environment to much say some experts, for a reintroduction to be considered for the foreseeable future.

Reintroduction -  The pros and cons.

Reintroduction is defined as attempting to re-establish a species to an area it once historically ranged but has become either extirpated or extinct.  Britain it has been suggested has a moral responsibility to attempt to right the wrongs previously contributing to the demise of large carnivores, while the Bern Convention (1979) and Rio Convention (1992) oblige the UK to help the recovery of populations of species native to Britain. There are problems with potential re introductions however, along with environmental change and an ever increasing human population, it is extremely difficult for scientists to predict how successful a reintroduction will be when the target reintroduction species has been absent from the landscape for a long period of time.There are options available which scientists and ecologists can use. Successful reintroduction's into analogous ecosystems elsewhere can illustrate possible implications of reintroductions into the target area. Secondly, controlled introductions into the proposed  area can help to assess feasibility of a future full reintroduction. IUCN guidelines however state that the cause of a species extinction must no longer be present before any such action can be put into place.

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Lynx  and wolves in Britain.

Lynx populations in Britain have been estimated to have reached the 7000 mark and their woodland range stretched from Scotland to as far down as Cornwall, England. The demise of the lynx came as a result of human deforestation, with the habitat  needed for both predator and prey depleted, both populations declined. When grazing by domestic animals from  farmers reduced remaining forest still further conflict between human  and predator as a result of livestock predation was inevitable. 
Wolves were common in southern England in the Saxon period which lasted from 410 to 1066 and would have out of preference targeted red deer as a prey species. In the 17th century though like the lynx and bears before them the wolf disappeared from  Britain. Hunting as a result of livestock predation and fear for human life is thought to be the main cause of the wolf's elimination from Britain.

Potential ecological impacts.

There are two ecological impacts caused as the result of the presence of predators. A density mediated affect as a result of predation and reduction of grazing pasture, and a no consumptive effect, where the foraging behavior and habitat use of prey species are affected. This is also referred to as creating a landscape of fear.

Deer populations in Britain are said to be ecologically unsustainable at present with areas of woodland so heavily grazed they will never recover. And this is where the landscape of fear principle could it has been suggested occur with the reintroduction of wolves as it has in Yellowstone National Park. A study found in areas classed as high risk predation areas plant growth increased on a yearly basis. The reintroduction of wolves it was concluded was an  act of management required for the recovery of riparian species and the protection of biodiversity.  Other ecological impacts potentially could include the provisioning of carrion for medium sized carnivores, however these could subsequently become prey items themselves. Passerine breeding success rates could also increase.  

Lynx however, are unlikely to create the same landscape of fear that it has been suggested wolves potentially could. This is illustrated by the findings of a Scandinavian study which found that despite 65% of roe deer fatalities being as  a result of lynx predation, no changes in habitat selection were found. This it has been theorised, is as a result of the territorial nature of roe deer.

There are also concerns over the impact lynx could have on the endangered capercaillie. Studies have found contrasting results in relation to  this point.  While Swedish lynx are found to include capercaillie in their diet, 29 radio collared lynx in Switzerland over a 10 year period provided just one instance of capercaillie in their diet out of recorded 617 prey items.  Intriguingly, 37 red foxes were also recorded potentially providing a help for gamekeepers and capercaillie alike. Despite this opposition argue that efforts should be concentrated on helping the aforementioned capercaillie and black grouse. There is a risk of competitive exclusion with wildcats however, due to differences in prey preferences, this is considered unlikely. 

Conflict and solutions  

Threat to human life is always going to be the greatest concern when the topic of reintroducing large carnivores arises however there are no recorded attacks by lynx on humans and wolf attacks are very rare.

Another issue of concern is predation of livestock, both wolves and lynx do take domestic animals. It has been shown however in some cases, wolves even when faced with  depleted natural prey availability and high densities of livestock nearby, will still show a clear preference for natural prey. Livestock were found too  take up a minority percentage of their dietary intake. 

Subsidies also offer a solution to loss of livestock to predation. In the Pidemont area of Northern Italy, a compensation plan to pay lump sums of money in the event of goat or sheep damage, is related to the flock size and starts after the event of the first attack. After this the compensation paid increases by 15 % for every attack that follows. The total amount of compensation is then shared between the owners of the flock animals with the amount of money received correlating with the amount of animals owned. It is thought that this system could be the reason there is not a greater level of opposition from Scottish farmers towards wolf reintroduction, as sheep barely make a profit and farmers could benefit more from them via a subsidies system. Veterinary checks on carcasses would have to occur however to prevent fraudulent claims. And in the case of lynx with better preventative measures and a greater tolerance towards problem animals, domestic predation and conflict with people has been found too significantly decrease.

So is there room for large carnivores in modern day Britain ? 

The idea of reintroducing the lynx would seem to be the most feasible particularly on island nature reserves or on enclosed eco-parks. In the two potential habitats for lynx in Scotland, after basing the densities of four species of deer; roe, red, sika and fallow deer, it has been predicted that suitable habitat in the highlands, potentially could be able to support 2.63 lynx 100 km2 and the southern uplands could support 0.83 lynx 100 km2 extending across the border and into the English section of the Kielder Forest. After this information had been applied to the amount of suitable habitat it has been estimated the highlands could support 400 lynx and the southern uplands 50. If this were to happen, Scotland would be supporting the fourth largest population of lynx in Europe.

A suggested location for a trial reintroduction of wolves is the Isle of Rhum Scotland, where wolves have never existed on the island. The reasoning the suggestion is an overly large population of deer and aside from Nature Conservancy staff no human inhabitants. This echoes of a similar trial in Coronation Island, Alaska during the year 1960, which ultimately failed as the deer with limited places to hide on a small island declined quickly in population leaving the wolves lacking food sources and ultimately led to their demise. It is thought that due to the large home range sizes and small population densities of large carnivores, the Scottish highlands is the only location a feasible population could be supported.

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So is Britain ready for a return of the  large carnivores ?

The lynx the evidence suggests is perhaps the most likely species to e reintroduced, wolves less likely and bears a very distant possibility. Prey sources are abundant, the required habitat available and space plentiful certainly for the lynx and quite possibly for the wolf as well. Changing peoples views on reintroducing large carnivores is potentially one of the biggest obstacles, and a trial reintroduction in a fenced areas  is almost certainly needed before a full reintroduction could take place. 

The thought of large carnivores once again stalking the woodlands of Britain is surely one that cannot fail to capture the imagination. How long before this idealization becomes reality if at all remains to be seen. Personally I long for the day when  the howls of the wolf echo around the woodlands of Britain once more and lynx are back living their secretive lives barely leaving a trace of their mysterious existence.

That's all for now thank you for reading, 
all the best, George.

Twitter @ReallyWildWykes

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