Restoring a desert ecosystem using soil salvage, revegetation, and irrigation

• Restoration can help reverse degradation and desertification.
• We tested how topsoil and irrigation affected survival of 23 perennial species.
• Topsoil salvage doubled plant survival.
• DRiWATER (slow-release water) increased survival by 50%; hand watering by 79%.
• Among species, survival of salvage forecasted ensuing field transplant survival.

Effective restoration techniques are needed in many arid lands for reversing degradation and desertification. In the Mojave Desert of the American Southwest, we tested experimental techniques for enhancing survival of salvaged perennial plants and their establishment on severely disturbed sites. Rooting hormone, slurry, and soaking treatments were ineffective at enhancing plant survival of salvage. Survival of salvaged plants after one year of nursery care was 48% (1017 of 2105 plants). Of these survivors, 50% survived 27 mo after transplanting back to field restoration sites. On restoration sites, irrigation increased transplant survival by 50% (DRiWATER, a slow-release gel) and 79% (hand watering), compared to no irrigation (35% survival). Providing salvaged topsoil as a growth medium, without irrigation, doubled survival, nearly equivalent to irrigating plants. Survival varied by an order of magnitude across 23 species, and species amenable to salvage also generally survived transplanting to field sites (r = 0.82 between salvage and transplant survival). Selecting species amenable to restoration and identifying treatments effective at enhancing survival can reestablish native perennial plants, often considered a first step in restoring desert ecosystems.