Places to see rare bumblebees
Salisbury Plain, Wiltshire
Salisbury Plain Training Area, owned by the Ministry of Defence, covers a very large area of Wiltshire; it is very roughly 20km across, east to west, and 10 across north to south, or approximately 14,000 ha. It is the largest surviving area of calcareous grassland in northwest Europe, and makes up nearly half of all the calcareous grassland surviving in the UK. Although many parts of the Plain are not especially rich in flowers, some are very good, and it is the vast area available overall that makes it special. Not surprisingly, the Plain also supports many rare plants and other animals, including for example huge populations of the marsh fritillary butterfly, a species that has declined dramatically elsewhere in the UK, and many breeding pairs of stone curlew. It is also the site where the great bustard was recently reintroduced to the UK from Russia. In total, the Plain supports more species of bumblebee than anywhere else in the UK; the ‘big six’ plus B. sylvarum, B. humilis, B. muscorum, B. soroeensis, B. ruderarius, B. jonellus and the very rare B. ruderatus. The cuckoo bees B. vestalis and B. rupestris are also common, while the rarer B. barbutellus and B. sylvestris occur occasionally. The area around Tilshead Park is particularly good for bumblebees, with large populations of B. sylvarum and B. humilis.
Access to the Plain is restricted, for obvious reasons. The center of the plain is regularly subjected to artillery bombardments! However, there is some excellent bumblebee habitat present in the eastern portion of the Plain, in areas where there is no live firing and where there are some public rights of way.
Salisbury Plain is a former haunt of B. subterraneus, and if this species still occurs in the UK this is perhaps the most likely location. The large size of the plain and limited access to many areas mean that the species may have been overlooked, although this must be considered unlikely.
Hebrides, western Scotland
A number of our rarer species can be seen on the Scottish Isles, most notably B. distinguendus, an exceedingly rare species now found only in the Hebrides, Orkney, Shetland and tiny populations on the mainland coast of north Scotland. Other species that can be seen include B. magnus, B. pascuorum, B. ruderarius, B. lapidarius, B. lucorum, B. soroeensis, B. hortorum and B. jonellus. B. muscorum, now very rare in England, is one of the commonest species, occurring on most islands. In the Outer Hebrides can be found the subspecies B. muscorum smithianus, a most impressive beast with a chestnut coloured thorax and black underside.
Agriculture in this region remains much less intensive than in most of the UK, and that is why so many rare species survive. The western coasts of some of the Hebridean Islands supports a very rare habitat, the machair, which is fantastic for wildflowers and bumblebees. It essentially consists of vegetated sand dunes, managed by low-intensity grazing and occasional planting of arable crops. The low soil fertility ensures that Fabaceae such as red clover and kidney vetch flourish, along with drifts of other flowers.
Islands particularly worth a visit for machair and bumblebees include South & North Uist, Coll & Tiree.
Castlemartin Range, Pembrokeshire
Castlemartin range is 2,381 ha in area, and lies on the southern coast of Pembrokeshire to the south-west of Pembroke. It is protected as part of the Pembrokeshire Coast National Park, and a small part forms the Castlemartin Cliffs and Dunes SSSI. Much of the Castlemartin Range was originally farmed as part of the Cawdor Estate. It was taken over for military training in 1939, and purchased by the MoD in 1948. This is undoubtedly why the area has survived as an excellent habitat for wildlife. During the last 60 years virtually no ‘improvement’ of land for agriculture has taken place.
The Range encompasses a range of different habitats including sand dunes, seas cliffs and large areas of unimproved grassland used for grazing sheep in winter. This practice is long-established, and appears to be a management regime that greatly favours bumblebees; the grazing maintains a mid-successional state but allows plants to flower during the summer. Sheep preferentially eat flower heads, so their absence during the summer is important. The main foodplants of bumblebees at this site are Rhianthus minor, Lotus corniculatus, L. pedunculatus, Trifolium pratense, Melilotus officinalis, Centaurea nigra, Odontites verna and Succisa pratensis (Carvell 2000).
Ten true bumblebees can be seen at Castlemartin; the ‘big six’ plus B. sylvarum, B. humilis, B. muscorum and B. jonellus (although the latter two species are scarce). This area thought to have one of the strongest surviving populations of B. sylvarum. The range itself is reasonably secure for the future. There are also organic farms in areas close to Castlemartin that support B. sylvarum, and in total the area occupied by this species may be up to 32 km2. This corner of Wales is possibly one of the best and largest bumblebee habitat remaining in the mainland UK, and every effort should be made to see that it remains so.
Romney Marsh and Dungeness, Kent
Not so long ago, in the 1980’s, this area had more species of bumblebees than any other site in the UK. It is a unique site, a large triangle of low-lying shingle projecting out into the English Channel, backed by marshland. A portion of the area is protected as an RSPB reserve. As with the machair, the low fertility is probably key to its botanical diversity and its value for bumblebees. The shingle also has little value for farming, and so has been largely untouched by agriculture except for some grazing. In summer the quantity of flowers such as viper’s bugloss, clovers and trefoils is astonishing, and clearly much appreciated by the bees. Rare species that can be seen here include B. muscorum, B. humilis, and B. jonellus. This was the last known location in the UK for B. subterraneus, a species not seen since the 1980’s. It also used to support the rare species B. ruderatus, B. sylvarum and B. ruderarius, but sadly these too seem to have vanished.
These declines are very likely the result of agricultural intensification across Romney Marsh. The marshland and wet meadows would have been traditionally managed by low-intensity grazing (when the land was dry enough to allow animals on) or by cutting for hay. Now much of it has been drained, ploughed, and is used for arable crops, while the remaining pasture is mostly ‘improved’. What was once a very large area of suitable bumblebee habitat has now shrunk to a few small fragments, notably the RSPB reserve. It would seem that these fragments were not big enough to support the long-term survival of the rarer bees.
Kenfig National Nature Reserve and Margam Moors SSSI, Glamorgan
Kenfig NNR comprises 513 ha of sand dunes, a remnant of a much larger dune system that once fringed the eastern shoreline of Swansea bay. The edges of the dune slacks support high densities of a number of plants that are bumblebee favourites, particularly red clover and water mint, while on drier areas there are good stands of viper’s bugloss, kidney vetch and red bartsia. In addition to the common bee species you can expect to see B. humilis here, and with a bit of luck also B. sylvarum and B. ruderarius.
Margam Moors SSSI is another area of dunes and flower-rich grassland just to the north of Kenfig, covering 108 ha. The vegetation and bee fauna are similar, although B. jonellus and B. muscorum have also been recorded recently. Neither Margam nor Kenfig is likely to be big enough to support viable populations of rare bumblebees on their own. However, they are close together, and in the area there are a number of other small fragments of dune systems and flower-rich grassland. Of course bees do not respect the boundaries of nature reserves, and so as far as the bees are concerned there is probably just one patchy population across the entire area.
These dune systems are regularly grazed, and if grazing is too intense in the summer this can have disastrous effects. Sheep in particular tend to eat all of the flowers, leaving nothing for the bees. As a result bee populations in recent years seem to have fluctuated wildly. Fortunately growing awareness of the value of these sites for rare bees has led to some areas being kept ungrazed each year, which should hopefully ensure that the future of the rare bees at these sites is reasonably secure.
Thames estuary, north Kent & south Essex
Along both banks of the Thames estuary are a number of sites where the BAP species B. sylvarum and B. humilis occur, together with all of the common species and also B. muscorum at some sites. Some of these sites are protected as nature reserves or have SSSI status, while others have no protection. They also comprise a range of habitats, including salt marshes, pasture and brownfield sites.
Among the sites where B. sylvarum may be seen are
a) Essex: East Tilbury Silt Lagoons (SSSI); Canvey Island (Safeway Northwick site); Wat Tyler Country Park; Hadleigh Castle Country Park.
b) Kent: The main areas is between Gravesend in the west, and Whitstable in the East, including Cliffe RSPB Reserve, Elmley Marshes RSPB Reserve and Elmley Trust Reserve on the Isle of Sheppey.
Some of these sites are well protected, primarily for their bird life, but the discovery of rare bumblebees here means that some attention is now being given to suitable management for them. However, many of the sites are less well protected, and management is poor or non-existent. Unlike most of the other sites that support rare bumblebees, there is a considerable human population in this area, and hence more pressure on land use. Some of the sites are threatened by development, particularly on Canvey Island, and at Murston, where one area of former bumblebee habitat has already been developed. The suitable sites are often surrounded by intensively farmed agricultural land of little value to bumblebees. Overall, the long-term survival of rare species such as B. sylvarum and B. muscorum in this area is not assured, and concerted conservation efforts are required.