The genus Bimastos is epigaeic, in that they are generally forest dwellers that utilize habitats of surface materials, leaf litter, rotting logs or concentrations of organic materials (James 2000). B. lawrenceae paratypes were collected from very moist sites or associated with small streams, with matted vegetation, moist humus or along logs. The holotype was obtained from a soil and vegetation sample, but the precise location was unclear (McKey-Fender et al. 1994). The Duck Lake specimen was found in a recent clearcut, but under bark, mosses and matted vegetation in a steep cold stream. The low elevation specimens were found in a wet muck skunk cabbage wetland along a busy forest road (McKey-Fender et al. 1994). James (2000) notes that epigeic earthworms would require a forest stand that permits the development of a sufficiently-deep leaf litter layer and/or coarse woody debris of sufficient size and decomposition state to harbour these worms. Marshall and Fender (1998) noted that native earthworm species were generally absent from the drier habitats of SE Vancouver Island; it is possible that this species is restricted to the wetter habitats of the west side of Vancouver Island. While one specimen was found in a recent clearcut, the effects of forest harvesting in terms of changes to microsite conditions are unknown.