Data from: Vertical partitioning between sister species of Rhizopogon fungi on mesic and xeric sites in an interior Douglas-fir forest

Understanding ectomycorrhizal fungal (EMF) community structure is limited
by a lack of taxonomic resolution and autecological information.
Rhizopogon vesiculosus and R. vinicolor (Basidiomycota) are
morphologically and genetically related species. They are dominant members
of interior Douglas-fir (Pseudotsuga menziesii var. glauca) EMF
communities, but mechanisms leading to their coexistence are unknown. We
investigated the microsite associations and foraging strategy of
individual R. vesiculosus and R. vinicolor genets. Mycelia spatial
patterns, pervasiveness and root colonization patterns of fungal genets
were compared between Rhizopogon species and between xeric and mesic soil
moisture regimes. Rhizopogon spp. mycelia were systematically excavated
from the soil and identified using microsatellite DNA markers. Rhizopogon
vesiculosus mycelia occurred at greater depth, were more spatially
pervasive, and colonized more tree roots than R. vinicolor mycelia. Both
species were frequently encountered in organic layers and between the
interface of organic and mineral horizons. They were particularly abundant
within microsites associated with soil moisture retention. The occurrence
of R. vesiculosus shifted in the presence of R. vinicolor towards mineral
soil horizons, where R. vinicolor was mostly absent. This suggests that
competition and foraging strategy may contribute towards the vertical
partitioning observed between these species. R. vesiculosus and R.
vinicolor mycelia systems occurred at greater mean depths and were more
pervasive in mesic plots compared to xeric plots. The spatial continuity
and number of trees colonized by genets of each species did not
significantly differ between soil moisture regimes.