Responses of Lumbricidae to saline inundation.
At two localities in northwest England that had recently been inundated by the sea, the decline in the density, biomass and species spectrum of Lumbricidae was proportional to the severity of inundation. Allolobophora spp. were dominant in all soils. Experimental flooding of soil with sea water demonstrated that Allolobophora spp. were not expelled as readily as Dendrobaena mammalis and Lumbricus spp. Of six species tested, all avoided 14o/oo salinity. Immersion in sea water of 29o/oo salinity was rapidly fatal to eight species tested; Allolobophora longa and Lumbricus terrestris being most resistant; lumbricids expelled from soil by salt water would, therefore, rapidly perish. Lumbricid distributions in the field were consistent with D.mammalis and Lumbricus castaneus being rapidly killed by saline inundation and Allolobophora spp. being relatively resistant. Soil analyses and laboratory experiments in which the worms were offered a choice of soil suggested that conditions in the less inundated soils favoured immigration of lumbricids. Since the viability of cocoons formed before flooding appeared to have been unaffected by inundation, both immigration and breeding of survivors of inundation in situ will facilitate recovery of lumbricid populations.