Llanelli Naturalists Newsletter - Summer 1993 - No 55
A.P. Fowles
A colony of wood ants is unmistakeable, but many naturalists are unaware that several species of Formica build similar wood edge nest mounds in Britain. Three species, the red wood ant Formica rufa, the hairy wood ant F. lugubris and the Scottish wood ant F. aquilonia, occur commonly in certain parts of Britain, and two of these occur in. Wales. The hairy wood ant, which is widespread in Scotland and northern England, is frequent in the conifer plantations of north Wales, and also inhabits a few oakwoods in Merioneth and Radnor. The red wood ant, a characteristic species of open woodlands in southern England, is thinly scattered in lowland woods across Wales. Identification of the two species is largely based on the degree of hairiness of the eyes and head.
The red wood ant would have been more common in Welsh woodlands that were coppiced in the past to provide fuel for the furnaces of the iron and lead mines, but the neglect of woodland management and the destruction of ancient woodland has caused a significant decline. This decline has largely gone unnoticed amongst conservationists in Wales and the current status of F. rufa in Wales is poorly known. A thorough search of the literature suggests that circa seventy-two colonies have been recorded in Wales, with concentrations in Gwent, northern Cardiganshire, and the Mawddach valley. of Merionethshire. Formica rufa has never been recorded from Pembrokeshire, Flintshire or Anglesey, it is probably extinct in Denbighshire, and it is undoubtedly extremely scarce in Breconshire and Carmarthenshire. There are no known records of rufa in north Wales since 1972, although it is suspected that several of the twenty-seven colonies reported in the past are probably still in existence. In mid and south Wales there is a total of only sixteen sites with post-1980 records of rufa - Monmouth (4), Glamorgan (1), Brecon (1), Radnor (2), Carmarthen (1), Cardigan (6) and Montgomery (1). Most of these consist of just one or two nests and only two sites, one in Radnor and one in Ceredigion, are known to support colonies with more than fifteen nests.
A small colony of red wood ants is present along a ride through the conifer plantation at Abergorlech but there have been no other recent records in the county. Wood ants in a conifer plantation near Felinfoel in the late 1970s may also have been F. rufa but this was not confirmed before the colony became extinct. Otherwise there is just a single record of a queen seen crossing a forestry track at Cwm Crychan in 1972.
Grid ref. Locality Last record
22/582345 Abergorlech 1992
22/838401 Cwm Crychan Aug 1972
Although some invertebrates are predators of F. rufa, with the exception of rare battles between neighbouring wood ant nests the only serious threat from predation is the occasional destruction of nests by green woodpeckers. The loss of woodlands due to clearance for agriculture and urban expansion has probably accounted for the extinction of a number of rufa colonies in Wales in the past but they are unlikely to be major threats in the future. The neglect of woodland management is probably the most serious threat facing the existing colonies in Wales as rufa is known to be very poor at colonising adjacent habitats once its nest sites become over-shaded (Welch 1978).
It is time that we gave some thought to the conservation of our red wood ants. This may seem strange when they are clearly not threatened in Britain as a whole and when each nest may slaughter up to six million woodland invertebrates each year. However, without taking care of our rufa colonies we stand to lose an important and interesting aspect of Welsh woodland ecology. In terms of species conservation, wood ant nests harbour a large number of myrmecophiles, invertebrates that live in close association with wood ants for all or most of their lives. Several of these species are national rarities and their conservation depends on the survival of wood ant colonies. In England and Wales, twenty-one species are entirely dependent upon wood ants for their conservation several more occur in Scotland only with aquilonia and lugubris) and twelve of these have been recorded from Wales. Also, the activities of wood arts affect the composition of the woodland invertebrate community, creating an ecologically unique balance of species. Although the nests of F. lugubris may provide a suitable habitat for scarce myrmecophiles, we are in danger of losing the last examples of wood ant dominated oakwoods in Wales.
We should recognise the importance of our own colonies and take steps to safeguard their future and the future of the community of woodland invertebrates they sustain.
Over the next couple of years the Countryside Council for Wales will be surveying the distribution of red wood ants in Wales to ascertain a true picture of its status. However, nests can be very localised and therefore over-looked. It would be a great help if naturalists in Wales kept us informed of any wood ants' nests they encounter. In Carmarthenshire there is little chance of the hairy wood ant occurring and nests can be presumed to belong to the red wood ant but specimens sent for confirmation will be welcomed. Old records of the presence of wood ants' nests are also of interest. Please contact: A. P. Fowles, Countryside Council for Wales, Plas Penrhos, Ffordd Penrhos, Bangor, Gwynedd LL57 2LQ.
