Large-scale diversity patterns in spore communities of arbuscular mycorrhizal fungi

Surprising little is known about the factors controlling Arbuscular Mycorrhizal (AM) fungal diversity and distribution patterns. A better understanding of these factors is necessary before mycorrhizas can be effectively managed for their benefits in ecosystem restoration and agriculture. The goal of this chapter is to examine the relationships between AM fungal diversity, plant diversity and latitude across a variety of vegetation types and disturbance regimes. We created a large database by compiling seven distinct datasets from across North America to test the hypotheses that 1) diversity of AM fungal communities should be positively related to plant diversity; 2) AM fungal diversity should be higher in low latitudes than in high latitudes; and 3) disturbance and land use should influence AM fungal diversity. The database was composed of 523 samples collected by research groups from Mexico and United States of America with eight different vegetation types and land uses. Abundance of 121 AM fungi taxa as well as data on geographic location, vegetation type, and disturbance history were included in the database. Contrary to our expectations, species richness and evenness of AM fungal spore communities were not correlated with plant richness or latitude. The influence of disturbance on AM fungal species diversity varied with climate. Our findings indicate that the factors controlling community diversity differ for plants and mycorrhizal fungi. Disturbance influences AM fungal spore diversity, and the outcome of these effects varies among ecosystems.