Rehabilitation of Degraded Rangeland in Drylands by Prickly Pear (Opuntia ficus-indica L.) Plantations: Effect on Soil and Spontaneous Vegetation

In arid and semi-arid lands, the spiny prickly pear (Opuntia ficus-indica) is an outstanding plant for soil conservation and restoration. To determine the role of Opuntia ficus-indica on vegetation recovery process in desertified areas of Southern Tebessa (Northeast Algeria), we investigated the effect of prickly pear plantation age and some soil properties (grain size, pH, electrical conductivity, organic matter, total nitrogen, available phosphorus, and CaCO3 equivalents) on native plant community. Vegetation cover and plant diversity were assessed by calculating the number of individual plants (N), species richness (S), their ratio (N/S), Shannon index, and Evenness in prickly pear plantation plots of different ages (control, 5 and 20 years). Even if surveyed soil parameters did not differ significantly among O. ficus-indica plantations, results of ANOVA testing the effect of Opuntia plantations on native vegetation traits revealed significant variation for plant abundance (P < 0.0001), N/S ratio (P = 0.003) and vegetation cover (P < 0.0001). Vegetation cover differed significantly with both prickly-pear plantation age (P=0.031) and seasons (P = 0.019). Tukey's tests revealed that all vegetation traits were significantly higher on prickly pear plantations than in control plots. Multiple comparisons also showed that plant abundance, N/S ratio and vegetation cover were significantly different between both young and old plantations and the controls. Prickly pear cultures facilitated the colonization and development of herbaceous species by ameliorating the severe environmental conditions. In conclusion, the facilitative effect of O. ficus-indica has been clearly demonstrated for both abundance and cover of native vegetation.