Arbuscular mycorrhizas influence plant diversity and community structure in a semiarid herbland

Abstract

Summary• The contribution of arbuscular mycorrhizas (AM) to plant community structure and diversity is reported here in an annual herbland in southern Australia.• Mycorrhizal colonization was reduced in field plots by applying the fungicide benomyl as a soil drench. The mycorrhiza-responsiveness of plant species was assessed in intact soil cores containing the indigenous AM fungi and in a pot experiment using an isolate of Glomus mosseae .• Glasshouse experiments showed that Medicago minima, Vittadinia gracilis and Velleia arguta were highly mycorrhiza-responsive, Salvia verbenaca became colonized but exhibited no growth response to AM, and Carrichtera annua remained uncolonized. There was no change in plant species richness in mycorrhizasuppressed field plots but diversity increased owing to an increase in evenness. Treatment had no effect on community productivity and therefore there was no relationship between mycorrhizal effects on diversity and productivity.• Mycorrhizal responsiveness was not a good predictor of species response to suppression of AM in the field. The mycorrhiza-responsive species V. gracilis and V. arguta were not affected by reduced mycorrhizal colonization in fungicide-treated plots, suggesting that competition from the mycorrhiza-responsive dominant M. minima offset the benefits of mycorrhizal association for these species.

Disruption of a Belowground Mutualism Alters Interactions Between Plants and Their Floral Visitors

“…By the end of this study, plots had received either two or three years of benomyl application. Benomyl is effective in reducing colonization of arbuscular-mycorrhizal fungi (AMF) Nichols 1988, Smith et al 2000) and has been widely used in ecological studies (e.g., Newsham et al 1994, 2002, O'Connor et al 2002, Callaway et al 2003. However, benomyl also causes a variety of unintended effects, including suppression of parasitic fungi (Newsham et al 1994) and nematodes (Schmidt et al 2000).…”

Diversidade de fungos micorrízicos arbusculares em pomar orgânico no semiárido cearense

“…Tem-se chamado atenção para a capacidade desses micossimbiontes em influenciar as relações interespecíficas das espécies vegetais na comunidade, como a competição por nutrientes, quando estes são escassos, com consequente alteração na diversidade e na estrutura de comunidades de plantas (O'CONNOR et al, 2002).…”

Arbuscular mycorrhiza enhanced arsenic resistance of both white clover (Trifolium repens Linn.) and ryegrass (Lolium perenne L.) plants in an arsenic-contaminated soil

“…Recently, it has also been demonstrated that arbuscular mycorrhizal (AM) associations can protect host plants under As contamination, even for the As-tolerant plant species, such as Chinese brake fern (Pteris vittata L.) (Liu et al, 2005;Chen et al, 2007b). Moreover, it is well known that AM symbioses have major influences on plant coexistence and plant community diversity (Zobel et al, 1997;O'Connor et al, 2002). Plants associated with AM fungi can successfully colonize sites contaminated by heavy metals, such as mine tailings that normally can hardly support any plant growth (Khan et al, 2000;Pennisi, 2004).…”