Soil amendment addition

Disturbed areas are often characterized by soils that are nutrient depleted and missing critical microbial communities [1] [2]. Planting or seeding in areas that are low in important soil components can limit restoration success. However, adding amendments to the soil, such as fertilizer or compost, often increases soil nitrogen and disproportionately benefits invasive species. Adding soil from healthy habitat can be helpful, but this approach can result in damage to undisturbed areas and should only be employed on very small scales. Native arbuscular mycorrhizal (AM) fungi can be an effective amendment, when accessible, but its effects are highly species specific [3]. For example, mesquite and yellow palo verde trees demonstrate positive short term responses to inoculation with AM fungi but blue palo verde shows no response [4]. Soils that are characterized by high saline should not be inoculated with fungi as the survival of the inoculants is likely to be very low [5]. Innoculating a restoration site with small amounts of soil from sites characterized by healthy native plant communities is also a good way to jumpstart the recolonization of beneficial bacteria and fungi.