Vegetation and Soil Environment Influence the Spatial Distribution of Root-Associated Fungi in a Mature Beech-Maple Forest

Abstract

Although the level of diversity of root-associated fungi can be quite high, the effect of plant distribution and soil environment on root-associated fungal communities at fine spatial scales has received little attention. Here, we examine how soil environment and plant distribution affect the occurrence, diversity, and community structure of root-associated fungi at local patch scales within a mature forest. We used terminal restriction fragment length polymorphism and sequence analysis to detect 63 fungal species representing 28 different genera colonizing tree root tips. At least 32 species matched previously identified mycorrhizal fungi, with the remaining fungi including both saprotrophic and parasitic species. Root fungal communities were significantly different between June and September, suggesting a rapid temporal change in root fungal communities. Plant distribution affected root fungal communities, with some root fungi positively correlated with tree diameter and herbaceous-plant coverage. Some aspects of the soil environment were correlated with root fungal community structure, with the abundance of some root fungi positively correlated with soil pH and moisture content in June and with soil phosphorous (P) in September. Fungal distribution and community structure may be governed by plant-soil interactions at fine spatial scales within a mature forest. Soil P may play a role in structuring root fungal communities at certain times of the year.In temperate forests, most trees form relationships with ectomycorrhizal (ECM) fungi, and the diversity of this fungal group alone can approach 100 species within a forest stand (17,20,60). The ECM mutualism may be necessary for the success of some native plant species, as approximately 90% of roots of some tree species are colonized by ECM fungi (65). Nevertheless, we still know surprisingly little about what controls the community structure and distribution of root-associated fungi in forest systems (44,46). The occurrence of root-associated fungi may broadly reflect soil environmental conditions and the presence of preferred plant hosts (28, 61), but how these factors interact to influence the diversity, distribution, and community structure of these fungi within forest habitat patches at a local scale is uncertain.The distribution of root-associated fungi may be primarily a species response to local soil environmental conditions. For example, both the quality (i.e., nutrient content) and the quantity of soil organic matter are known to influence the diversity of ECM communities (18,20,32). ECM fungi also vary in drought tolerance (14, 36), resistance to fire (61, 65), and tolerance to soil acidity (19) and temperature (56). Changes in soil chemistry, especially as they relate to pH and the availability of nitrogen (N) and phosphorous (P), might favor selection of fungi most capable of tolerating environmental extremes (2,28,29).Plant distribution and identity may, however, play the strongest role in structuring the below-ground diversity of rootassociated fung...

Stipitate stereoid basidiocarps have evolved multiple times

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Soil Microbial Community Successional Patterns during Forest Ecosystem Restoration

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Seasonal variation in mycorrhizal fungi colonizing roots of Allium tricoccum (wild leek) in a mature mixed hardwood forest

“…Within Stebbins Gulch, the sampling location was an 80-ha, old-growth beech-maple stand and is the same site as in previous work exploring mycorrhizal fungi and soil microbial diversity (Burke et al 2009. The stand is dominated by an overstory of Fagus grandifolia (American beech), Acer saccharum (sugar maple), and Liriodendron tulipifera (tulip popular), a sub-canopy dominated by F. grandifolia, A. saccharum, and Lindera benzoin (spicebush), and a herbaceous understory comprised mostly of spring ephemerals and dominated by A. tricoccum (wild leek) and Dicentra canadensis (squirrel corn).…”

“…The site is characterized by acidic, moderately drained silt loam soil with a mean pH of 4.0±0.1 (measured in H 2 O), and it receives precipitation averaging 116 cm per year, including an average of 287 cm of snowfall per season (28.7 cm rainfall equivalents). For more detailed information about the field site, see Burke et al (2009Burke et al ( , 2012.…”