Three major classes of symbiotic fungi were identified in the roots of native grasses and shrubs on arid rangelands of the southwestern U.S. The first class is vesicular-arbuscular mycorrhizae, common to most higher plants. These fungi enhance nutrient and water uptake in plants. The second major class of symbiotic fungi are common soil or saprobic fungi. Because of their association with the host plant their capacity is enhanced to access nutrients from immobile inorganic and complex organic resources and supply them to the plant. One demonstrated benefit of a saprophytic seed-borne fungus, Alternaria alternata, was that it decomposed the seed capsule at germination and transferred nutrients to the germinating seedling, improving chances for survival and establishment. 'These fungi likely play a role in the management of carbon resources in the ecosystem. Third major class of fungi regularly associated with grass and shrub roots were Chytridiomycetes, a primitive aquatic fungus. These fungi appear to regulate the colonization by the other two fungal classes. These fungi, acting in concert with each other, enhance nutrient and water uptake of native plants. They directly affect survival ability and competitiveness of all plant species in arid rangelands. We are researching these fungi because we think that new technologies for rangeland revegetation of degraded areas will require the presence of these fungal classes for successful reestablishment and survival of native plant species.