Following on from last week’s article about UK birds this piece looks at mammals in the UK which were once extinct or close to it in many UK counties and are now making a comeback, although they still may be threatened.
Polecat (Mustela putorius)
Polecats where widespread across Britain up until the 19th century. However towards the end of the 19th century, leading to the early 20th century they were nearing extinction. Hunting of this species mainly occurred because they were thought of as a pest by gamekeepers. This along with habitat destruction resulted in their population being significantly reduced to very low levels. Once hunting was reduced, from around the 1950s the polecats began to re-colonise areas and they can now be found in Wales (this was always their stronghold), areas of England as well as Scotland, where some reintroductions have taken place. Interestingly though the polecat was never established in Ireland.
Pine marten (martes martes)
In the past pine martens were persecuted for their fur and by gamekeepers, as well as other problems such as habitat destruction contributing to their population decline. Originally found across Britain, by around 1926 the main population was located in a small area of Scotland, having been wiped out from most other areas. With hunting and habitat destruction reduced, pine martens began to increase their range again. Now a population of around 4,000 animals exists in Scotland. Extinct in England in the 1900s, there have since been several recordings of pine marten from various counties such as Cumbria and Shropshire. Currently a ‘Pine Marten Recovery Project’ is being carried out which translocated Scottish pine martens to Wales in the autumn of 2015 (click here). They can also be found in Ireland. Although this mammal is still threatened there is hope that populations will continue to increase.
European otter (Lutra lutra)
Otter numbers declined dramatically during the 1960s-70s due to wetland drainage and pollution in rivers, with heavy use of toxic pesticides, such as organo-chlorine pesticides, being devastating to their population. Otter numbers were at an all-time low from the 1970s-80s, and they were close to extinction. However damaging pesticides were banned, and water quality in many areas began to recover therefore allowing fish populations to also increase. Over time otters started to recolonise areas and can now be found in every English county, with Scotland having always been a stronghold for this species.
Wild boar (Sus scrofa)
Wild boar were once native to the UK but became extinct about 700 years ago. Around the 1980s boar farming became popular and it is thought that boar either escaped or were illegally freed into the countryside around this time. Viable ‘wild’ populations of this animal were established by 1998. The largest population of wild boar is located in the Forest of Dean. The original population here was increased in 2004 when approximately 60 farmed boars were illegally dumped and the two groups came together. The population of boar in the forest is now thought to be more than 800. Despite wild boar once inhabiting Britain their status and classification as a ‘native’ or ‘non-native’ species is still debated. They are however thriving in some areas, which is causing conflict, due to for example their habit of rooting up earth, the threat they cause to traffic as well as issues such as the controversial cull.
European beaver (Castor fiber)
In the 16th century beavers throughout Britain were extinct, due to overhunting for fur and castoreum, a glandular oil. Reintroductions, whether licensed or illegal, have since occurred meaning several populations of beaver can now be found in the UK. The Scottish Beaver Trial released beavers into Knapdale, Scotland, in 2009. Now with the trial over the decision regarding these beaver’s future is being decided by the Scottish Government. Elsewhere in Devon a population of beaver established themselves, the origin of this population was however unknown. After being captured and tested the beavers were re-released. Monitoring of this wild population is now being undertaken to see how they affect the surrounding area and wildlife, as a five year licence was granted by Natural England last year. For a species which was once extinct in the UK it is a success that there are now ‘wild’ populations, even if heavily monitored. Only time will tell whether this species will be able to stay for good, as there is still conflict surrounding their presence. This keystone species is significant in creating wetland habitat for other species as well as regulating flooding so it will be interesting to see what effect the Devon population has on the countryside.