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

Abstract

 Degradation of land in vulnerable areas can be significantly reduced by the maintenance or establishment of plant cover and diversity. Animals can facilitate plant diversity by grazing, by dispersing seeds or by contributing, through excreta, to the heterogeneous distribution of nutrients in soil. We investigated the latter property by examining the effects of rabbit (Oryctolagus cuniculus L.) dung deposition on soil properties in three adjacent plant communities at a semi-arid site in south-east Spain. Rabbit faecal pellets had concentrations of total N and P comparable to dung of stock animals, with K and Mg somewhat lower, although decomposition rates at this site are evidently very low. There was no significant difference in pH, but conductivity and concentrations of organic C, N (as NH₄ ⁺ and NO₃ ^–), K, P and Mg in soils from rabbit latrines were significantly greater relative to controls in each community. Barley plants grown as a bioassay of soil fertility had significantly greater total biomass, and lower root : shoot ratios in latrine compared to control soils. There were differences among communities in conductivity and concentrations of N, P and organic C under latrines which were reflected in the bioassay. Although latrines only comprised approximately 0.1% of the ground surface area in each community, they make significant localised contributions to soil fertility and may therefore be important in establishing and maintaining plant cover.