The contribution of rabbits (Oryctolagus cuniculus L.) to soil fertility in semi-arid Spain

Degradation of land in vulnerable areas can be significantly reduced by the maintenance or establishment of plant cover and diversity. Animals can fac ilitate plant diversity by grazing, by dispersing seeds or by contributing, through excreta, to the heterogeneous distribution of nutrients in soil. W e investigated the latter property by examining the effects of rabbit (Oryc tolagus cuniculus L.) dung deposition on soil properties in three adjacent plant communities at a semi-arid site in south-east Spain. Rabbit: faecal p ellets had concentrations of total N and P comparable to dung of stock anim als, with K and Mg somewhat lower, although decomposition rates at this sit e are evidently very low. There was no significant difference in pH, but co nductivity and concentrations of organic C, N (as NH4+ and NO3-), K, P and Mg in soils from rabbit latrines were significantly greater relative to con trols in each community. Barley plants grown as a bioassay of soil fertilit y had significantly greater total biomass, and lower root:shoot ratios in l atrine compared to control soils. There were differences among communities in conductivity and concentrations of N, P and organic C under latrines whi ch were reflected in the bioassay. Although latrines only comprised approxi mately 0.1% of the ground surface area in each community, they make signifi cant localised contributions to soil fertility and may therefore be importa nt in establishing and maintaining plant cover.