Great Basin Naturalist


Mycorrhizal fungi are thought to benefit associated plant species via enhanced nutrient uptake and/or improved water relations. However, detailed descriptions of the components of mycorrhizal colonization and mycorrhizal hyphal growth are not available for Artemisia tridentata. This species occupies sites characterized by relatively low levels of both soil nutrients and moisture. We studied patterns of vesicular, arbuscular, and hyphal mycorrhizal colonization, mycorrhizal hyphal lengths, and soil moisture associated with two subspecies of A. tridentata over a 2-year period. A. tridentata ssp. vaseyana (ATV) is generally associated with more mesic and slightly higher elevation sites compared to A. tridentata ssp. tridentata (ATT). Nearly twice as much precipitation was received the first year compared to the second. In general, there were higher levels of colonization and hyphal lengths associated with ATV than with ATT. The ATV site received slightly more precipitation and was lower in available nutrients than the ATT site. Hyphal lengths and arbuscular colonization appeared more responsive to precipitation than were either vesicular or hyphal colonization. Hyphal colonization did not necessarily follow the same temporal pattern as hyphal lengths. Thus, mycorrhizal activity was greater for the subspecies that received slightly more precipitation and occupied a site lower in available nutrients. Arbuscular colonization and hyphal lengths appeared to be most closely associated with soil moisture and thus plant activity.