Earthworms of an Urban Cemetery

Kevin R. Butt¹, Christopher N. Lowe¹ and Pam Duncanson²

¹School of Natural Resources, University of Central Lancashire, Preston, PR1 2HE, UK

²Lancashire County Council, Preston Cemetery, New Hall Lane, Preston, PR1 4SY, UK

Cemeteries often present large grass-covered spaces within urban settings. This work set out to obtain data on the earthworms associated with a cemetery in the centre of the city of Preston. Objectives were to unearth which species were present and in what numbers, but more directly to ascertain the status of Lumbricus terrestris. This species is of interest as it is reputed to be able to burrow to a depth of 2- 3 metres (Darwin, 1881). Therefore in the given setting, the relationship of such burrows with graves was something to explore, as it has been the subject of folklore for centuries.

General sampling employed a number of methods, such as digging and hand-sorting of soil and mustard vermifuge extraction. Two parts of the cemetery, one older with burials back to Victorian times and the other, brought into use since the 1950s, were both examined. For legal and moral reasons no sampling took place upon or immediately beside any point of human burial. L. terrestris burrows were examined following the resin cast method of Shipitalo and Butt (1999) with acrylic paint added for clarity.

Nine relatively common species of earthworms were located. Sampling in September, L. terrestris burrows were found to a depth of 0.5 m in the old cemetery in a clay soil, water-logged at depth. These burrows were of the type normally associated with this species, i.e. near vertical and little branched. In the new cemetery L. terrestris burrows were very different in form. Greatest burrow depth was to 0.3 m and these were often branched, with a mean of 1.2 divisions below 0.1 m (max. = 8). Nevertheless the mass of the adult animals taken from both sites did not differ significantly.

The branching nature of the burrows was caused by a limited soil layer in the new cemetery. Here sand was extracted historically and the void filled with refuse and rubble before covering with a tough impervious “concrete” layer. This prevented earthworm burrows extending beyond it. The “soil” above was littered with building rubble and made creation of vertical burrow difficult. However L. terrestris was able to colonise and survive in this area, demonstrating a remarkable plasticity in burrowing behaviour.