Melanic moths and charges in epiphytic vegetation in north-west England and north Wales

In 1973 the appearance and epiphyte cover of tree trunks was examined along a 125 km cline of melanic frequency in the peppered moth in NW England and N Wales. The sampled sites were resurveyed in 1986. There has been a marked increase in the crustose lichen Lecanora conizaeoides at the eastern end of the transect, an increase in lichen diversity in the middle of the transect and a possible decline in large foliose forms at the western end. These changes are discussed in relation to the eastward shift of the cline in melanic frequencies in the moth.