Rodent dispersal of fungal spores promotes seedling establishment away from mycorrhizal networks on Quercus garryana

Abstract

With global warming and the possible decline of conifers, more habitat may be available to oaks, particularly at higher elevations and more northerly latitudes. Whether oaks expand into new habitats will depend on their ability to disperse and establish at the margins of existing woodlands. Because oaks have a symbiotic relationship with ectomycorrhizal fungi, range expansion requires dispersal of both symbionts: the acorns and the mycorrhizal inoculum. Little is known of this dual dispersal. Here we assess the availability of ectomycorrhizal inoculum as a function of the distance from mature oaks. We examined soil cores for ectomycorrhizal roots and rodent fecal pellets for fungal spores along transects away from mature trees of Quercus garryana Dougl. ex Hook., and planted acorns as bioprobes. We identified spores by microscopy, and mycorrhizas by DNA sequences of the ITS region. Mycorrhizas were present in soil cores 5 m from parent trees, but not beyond. Spores of hypogeous fungi were found in rodent fecal pellets at distances up to 35 m from mature trees. Hypogeous fungi formed ectomycorrhizas with first-year seedlings within the root zone of mature trees and with second-year seedlings beyond the root zone. These data indicate that for seedlings near mature trees, the source of fungal inoculum was the mycorrhizal network of mature trees, and for seedlings beyond that, rodents dispersed the inoculum. We conclude that rodent dispersal of fungal spores promotes seedling establishment away from mycorrhizal networks in Q. garryana.

Prescribed Fire Effects on Deciduous Oak Woodland Stand Structure, Northern Diablo Range, California

“…Seedling-sized regeneration densities were often highest on sites that supported relatively high tree stocking (tree density, cover, or basal area). This association may be caused by relatively abundant regeneration sources on such sites (e.g, acorns or root sprouts), and facilitated by presence of oak-associated mycorrhizae (Frank et al 2009). Relatively benign site quality may also explain the positive association of seedling-sized regeneration with Oregon white oak driplines; adult tree presence indicates site or microsite suitability, and the trees may ameliorate the harshness of microsite conditions (Carvell and Tryon 1961).…”

The occurrence of heat-resistant species of Trichophaea abundans in different types of soil in Slovakia and Czech Republic

“…T. abundans was also reported by Raja et al (2007) (Mouchacca 2000). This was observed for isolates from burned soils (Wicklow 1988;Kubátová et al 2002;Jumpponen & Johnson 2005;Foster & Bills 2011), ectomyccorhizal species (Tedersoo et al 2006;Shefferson et al 2008;Cavender-Bares et al 2009;Frank et al 2009;Rubini et al 2009;Taylor et al 2010;), and those from dung (Doveri 2011). As a result of the rarity that T. abundans is isolated from a number of substrates in the literature, and in the current study, we suggest that it is likely a rare, or low abundance species.…”

“…Roxon & Batra (1973) described formation of apothecia on common laboratory media of T. abundans and T. hemisphaeroides. The occurrence of T. abundans from decaying wood, partially decayed oak litter and garden soil is presented by Moore-Landecker (1988), from South Africa by Coetzee & Eicker (1994), from California by Perry & Pfister (2008) and as rootassociated species formed ectomycorrhizae with many sorts of plants by Frank et al (2009), Rubini et al (2009), Shefferson et al (2008, Tedersoo et al (2006), and Kipfer et al (2010). T. abundans was also reported by Raja et al (2007) (Mouchacca 2000).…”

“…A few species, T. woolhopeia (Frank et al 2009;. Rubini et al 2009;Shefferson et al 2008;Tedersoo et al 2006) and T. hybrida (Cavender-Bares et al 2009), form ectomycorrhizal associations (Taylor et al 2010).…”

Phytosanitary problems detected in black truffle cultivation. A review

“…These rodents cause wounds in the root neck, and may lead to tree death. However, they play an important role in the dispersion of spores (Frank et al, 2008).…”