Spatial distribution of fungal communities in a coastal grassland soil

In grasslands, saprotrophic fungi, including basidiomycetes, are major decomposers of dead organic matter, although spatial distributions of their mycelial assemblages are little described. The aim of this study was to characterise the scale and distribution of saprotrophic fungal communities in a coastal grassland soil using terminal restriction fragment length polymorphism (T-RFLP). Soil fungi were sampled at Point Reyes, California, USA, by taking forty-five 26 mm diam. cores in a spatially defined manner. Within each sampled core, complete core sections at 1–2 cm and 14–15 cm depths were removed and sub-sampled for DNA extraction and amplification using the primer pairs ITS1F-FAM/ITS4 (general fungi) or ITS1F-FAM/ITS4B (basidiomycete-specific). Nonmetric Multidimensional Scaling showed that general fungal communities could be clearly separated by depth, although basidiomycete communities could not. There were no strong patterns of community similarity or dissimilarity for general or basidiomycete fungal communities at horizontal geographical distances from 25 cm to 96 m in the upper horizon. These results show considerable vertical, but little horizontal, variability in fungal community structure in a semi-natural grassland at the spatial scales measured here. 2008 Elsevier Ltd. All rights reserved. Little is known about the vertical and horizontal distributions of decomposer fungal communities as mycelia in grassland soils (e.g. Feeney et al., 2006). Even to begin to develop a more general understanding of spatial patterns of fungal community structure, more studies describing vertical and horizontal patterns are necessary. To start to fill this gap, we carried out a study examining vertical (2–15 cm depth) and horizontal (25 cm–96 m) patterns of fungal community composition in a coastal grassland, using T-RFLP. We characterised general fungal communities, and basidiomycete communitiesmore specifically to seewhether this group differed in spatial structure. The study site (38 20N, 122 530W) was located on a low ridge (20–30 m a.s.l.) at Point Reyes National Seashore, California, USA. The area is extensive coastal grassland interspersed with coastal scrub dominated by Baccharis pilularis. Typically, the A1 horizon of this Inceptisol is a brown sandy loam about 30 cm in depth (pH 5.6– spheric and Environmental ter, Oxford Road, Manchester