Associations between arbuscular mycorrhizal fungi and Sporobolus wrightii in riparian habitats in arid South-western North America

Seasonal dynamics of arbuscular mycorrhizal (AM) colonization of Sporobolus wrightii and AM fungal communities were assessed at four riparian sites in south-east Arizona which represented upper terrace or lower floodplain habitats and perennial or intermittent river reaches. Colonization was co-ordinated with growth/reproductive stages of plants at three sites with higher levels from February to May when plants were primarily vegetative and lower levels in September and December during seed set and onset of dormancy. Fifteen species of AM fungi were associated with S. wrightii, includingGlomus , Acaulospora, Paraglomus and Archaeospora species. Species richness ranged from 9 to 13 AM fungal species per site.