Biodiversity

Chough (Pyrrhocorax)

alt=Mawddach Estuary

Biodiversity in Snowdonia

Snowdonia is synonymous with extensive areas of windswept uplands and jagged peaks. Apart from the beauty and charm of its high mountains, Snowdonia has inspiring semi-natural habitats, which are a product of both natural forces and human activities. Due to its location on the western edge of Europe, Snowdonia is swept by warm, wet weather, making it an ideal home for thousands of species and their habitats. Many of these species and habitats are of international importance, some of which cannot be found anywhere else in the world!

Here are just a few examples of the species which call Snowdonia their home:

Lesser horseshoe bat (Rhinolophus hipposideros)

One of the smaller species of bat found in the UK, Snowdonia is a stronghold of the lesser horseshoe bat, accounting for over 25% of the total UK population. Reasons for their decline include agricultural intensification and a decline in suitable roosting sites. Although originally cave dwellers, the lesser horseshoe bat have adapted and summer colonies are now usually found in the roofs of large rural houses and outbuildings. They hibernate from early autumn (September/October) until spring (April), using caves, mine shafts and cellars. Mating takes place in autumn, with the young being born the following June/July. They feed within lowland valleys and their diet consist of a wide range of invertebrate species, including flies, small moths, caddis flies, lacewings, beetles, small wasps and spiders. You are most likely to spot a lesser horseshoe bat emerging from summer roosts about half an hour after sunset, with peak activity recorded at dusk and dawn. Like all native bat species, the lesser horseshoe bat is protected under both UK and European legislation.

Lesser Horseshoe Bat (© SNPA)

Lesser Horseshoe Bat (© SNPA)

Pine Marten (Martes martes)

The pine marten is a medium sized mustelid found in areas of woodland, mainly coniferous, and open uplands. They are slender animals, with dense brown fur, long bushy tails, and white patches (often referred to as ‘bibs’) on their chests. Hunting usually occurs on the ground, where they feed on a range of small mammals, birds, fruit and invertebrates. Pine martens mate in the summer months, although pregnancy is delayed until the following January. The litter is then born the following March or April. Once found throughout Britain, numbers have declined rapidly over the last 200 years due to loss of habitat, persecution by game keepers, and hunting for their fur. Whilst the number of pine martens within Snowdonia is unknown, they have been recorded regularly within the area during their period of decline. They are protected under the Wildlife and Countryside Act 1981 (as amended) within the UK.

Chough (Pyrrhocorax pyrrhocorax)

The chough is the rarest species of crow breeding in Britain. Similar in size to a jackdaw, it has a red bill and legs, which distinguishes it from other members of the crow family. Chough have a westerly distribution within the UK, and although usually found in coastal locations, in Snowdonia they are often found inland in rugged hills. The inland population breeds in a number of different sites, from crevices in cliffs and quarries to disused buildings and mine shafts. Chough are usually monogamous, although they may seek new partners after several years of unsuccessful breeding. UK populations have a specialised invertebrate diet, which contrasts with the omnivorous diets of most other British corvids. Persecution and agricultural intensification has lead to a decrease in chough numbers over the last 150 years.

Pine Marten (© SNPA)

Pine Marten (© SNPA)

Chough (© Jean-Jacques Boujot)

Chough (© Jean-Jacques Boujot)

Twite (Carduelis flavirostris)

A small streaky brown finch, Twite is a characteristic bird of the moorland fringe. Although they nest on heather moorlands, they feed on a variety of grassland habitats and will travel up to 2.5km from the moorland edge to reach food. Twite have seen a dramatic decline in numbers throughout the UK since 1800, with factors such as changes in agricultural techniques and heather burning having a major influence. Within Snowdonia, twite is most likely to be spotted feeding within the fields of Nant Ffrancon and the surrounding area.

Peregrine Falcon (Falco peregrinus)

A large and powerful bird, the peregrine falcon has long, pointed wings and a relatively short tail in comparison to other birds of prey. Although similar in appearance, female peregrine falcons are often up to 30% larger than their male counterparts. The back and wings of adult peregrines are bluish/grey in colour, with a black ‘moustache’ around the beak, which contrasts with the white of the face. They are often found within the upland areas of Snowdonia, where they are resident throughout the year. Numbers declined dramatically during the 19th and 20th century due to persecution by game keepers and an increase in the use of agricultural pesticides. However, numbers have recovered steadily since the 1960’s as a result of a ban on the use of certain chemicals within pesticides and due to increased conservation efforts.

Twite (© Mike Pennington)

Twite (© Mike Pennington)

Peregrine Falcon (© Stefan Berndtsson)

Peregrine Falcon (© Stefan Berndtsson)

Freshwater Pearl Mussel (Margaritifera margaritifera)

The freshwater pearl mussel has a black or dark brown shell, grows to 15cm in length and is renowned for producing dark coloured pearls. It has a complex life cycle; the free swimming larvae develop as parasites on the gills of fish, where they develop into young mussels which leave the fish to settle amongst gravel and stones on the river bed. Freshwater pearl mussels prefer fast running, cool waters, low in calcium. Incredibly, they can live for more than 100 years, making them one of the longest-living invertebrates on Earth! They feed by drawing in river water and filtering out fine particles, with adults being able to filter more water daily than we use in an average shower! It is confined to northern and western Europe, a distribution mirrored in Britain. Few populations are known in Snowdonia despite historical records dating back for many centuries. Over exploitation by fishermen is primarily responsible for massive declines in their numbers and range. Other reasons for their decline includes water pollution and engineering work in rivers such as the construction of weirs or deepening of pools. Drier summers as a result of climate change could become an increased threat over coming decades.

Glutinous Snail (Myxas glutinosa)

A small freshwater snail, the glutinous snail is one of the rarest in Europe. It gains its name because when active, the translucent mantle is extruded across almost the entire body-whorl and spire of the shell, leaving only a narrow crescentic area through which the shiny surface of the shell is visible. Thought to be extinct in Wales, it was rediscovered at Llyn Tegid in 1998, in an area where it had not been seen since 1952. This is now thought to be the only viable population within Snowdonia. The glutinous snails habitat requirements includes clean, calm fresh water lakes or rivers. Threats to its existence include the isolation of the population, pollution, increased recreational activities and fluctuations in water levels.

Freshwater Pearl Mussel (© NRW)

Freshwater Pearl Mussel (© NRW)

Glutinous Snail (© NRW)

Glutinous Snail (© NRW)

Y Gwyniad (Coregonus pennantii)

Coregonus lavaretus are a species of whitefish known locally as Y gwyniad, and are thought to be present in only one lake throughout Snowdonia, at Llyn Tegid in Bala. This population has been isolated from other UK populations in Scotland and England since at least the last ice age, and as a result, a degree of genetic variation has been demonstrated between these populations. Y gwyniad require relatively large deep lakes with clear well-oxygenated water. However, this population of subspecies face threats such as eutrophication of the lake, siltation of spawning grounds and the introduction of new fish species to Llyn Tegid. Although the population size of y gwyniad within Llyn Tegid is unknown, surveys undertaken during the 1990’s suggest the lake supports a total population of over 20,000.

Snowdon Beetle (Chrysolina cerealis)

The small Snowdon beetle has a brightly coloured red, gold, green and blue striped elytra which accounts for its European name, the Rainbow leaf beetle. They live on a base-rich scree, where grasses such as the common bent grass and sheep’s fescue grow alongside the beetle’s main food source, wild thyme. The adult beetles will lay their eggs on grass blades. Despite a relative abundance of suitable habitat within the National Park, the beetle is only found in a handful of sites on Snowdon itself, and perhaps Cwm Idwal. The Snowdon beetle is vulnerable to factors such as grazing density and climate change.

Gwyniad (© SNPA)

Gwyniad (© SNPA)

Snowdon Beetle (© Udo Schmidt)

Snowdon Beetle (© Udo Schmidt)

Snowdon Lily (Lloydia serotina)

The Snowdon lily is a delicate, artic-alpine flowering plant which has grass like leaves. Although it has wide spread distribution in alpine and arctic regions, Snowdonia is its only known location within the UK. Here, they grow on north/north-east facing cliffs, and can be found in a few inaccessible ledges and rock faces, out of reach of grazing animals. It is thought to have survived on high mountains tops within Snowdonia since the end of the last ice age, on areas which remained free from ice sheets and glaciers. Current threats to the Snowdon lily include overgrazing by sheep and wild goats, climate change and genetic erosion.

Large Heath (Coenonympha tullia)

The Large Heath is a medium sized, greyish brown butterfly which is invariably associated with areas of bog habitat but also degraded peatland and damp, acid moorland. It has a characteristic pattern of ocelli, or ‘eye spots’, which are most easily visible on the underside of the wings. The species can be distinguished from its ubiquitous relative, the Small Heath, by the more prominent ocelli, together with the larger size and often wetter habitat preference. In Snowdonia all the known colonies occur on upland sites. These are mostly categorised as blanket bog but there is one important colony on Cors Goch, a raised bog south of Llyn Trawsfynydd. The presence of Hare’s-tail Cottongrass (Eriophorum vaginatum), and/or White Beak-sedge (Rhynchospora alba), these being the larval foodplants, and Cross-leaved Heath (Erica tetralix) which is favoured by the adults for nectaring, are probably essential constituents of the butterfly’s habitat. Numbers have declined dramatically over the last few decades due to habitat fragmentation, drainage of bog sites and change in traditional agricultural practices.

Snowdon Lily (© SNPA)

Snowdon Lily (© SNPA)

Large Heath (© Ryan Hodnett)

Large Heath (© Ryan Hodnett)