Does grassland vegetation drive soil microbial diversity?

Abstract

Does plant diversity drive soil microbial diversity in temperate, upland grasslands? Plants influence microbial activity around their roots by release of carbon and pot studies have shown an impact of different grass species on soil microbial community structure. Therefore it is tempting to answer yes. However, evidence from field studies is more complex. This evidence is reviewed at three different scales. First, studies from the plant community scale are considered that have compared soil microbial community structure in pastures of different vegetation composition, as a consequence of pasture improvement. These show fungi dominating the biomass in unimproved pastures and bacteria when lime and fertilizers have been applied. Secondly, evidence for interactions between individual grass species and soil microbes is discussed at the level of the rhizosphere, by considering both pot experiments and field studies. These have produced contrasting and inconclusive results, often due to spatial heterogeneity of soil properties and microbial communities. In particular, increased soil pH and fertility in urine patches and other nutrient cycling processes interact to increase the spatially complexity of soil microbial communities. Finally three studies which have measured microbial community structure in the rhizoplane are considered. These show that bacterial diversity is not directly related to plant diversity, although fungal diversity is. In addition, the soil fungal community has been demonstrated to have an effect upon the composition of the bacterial community. We suggest that while current vegetation influences fungal communities (particularly mycorrhizae) and litter inputs fungal saprotrophs, bacterial community structure is influenced more by the quality or composition of soil organic matter, thereby reflecting carbon inputs to the soil over decades.

Ecological succession reveals potential signatures of marine–terrestrial transition in salt marsh fungal communities

“…Thus, the natural dynamics of plant colonization along the salt marsh successional gradient is likely to modulate the belowground SOM, which is directly intertwined with shifts in soil fungal communities. The influence of SOM on soil fungal communities has been previously reported (Hartmann et al, 2009;Millard and Singh, 2010); not only the quantity but also the quality status and turnover rate of SOM were found to influence specific fungal populations along an ecosystem landscape (Zinger et al, 2011). Yet, in our study, it appeared that, at a local scale, the magnitude of the shifts in SOM quantity and quality did not exceed the effects imposed by the dominant vegetation, resulting in a lowered fungal turnover within sites.…”

Microbial Community Structure and Activity Linked to Contrasting Biogeochemical Gradients in Bog and Fen Environments of the Glacial Lake Agassiz Peatland

“…Unpublished data from our group in another peatland site show a sharp decline of fungal 18S gene abundance below 50 cm, further supporting the potential importance of oxygen governing the abundance and activity of fungi. Several studies have demonstrated the relationship between fungal community distribution pattern and plant species composition in mineral soils (50,53). However, to our knowledge, this is the first study to report the feature that fungal community pattern differentially responds to quantity, quality (e.g., C/N ratio), and reactivity of DOM in peatland ecosystems.…”

The effects of grassland degradation on plant diversity, primary productivity, and soil fertility in the alpine region of Asia’s headwaters

“…The decrease in APB with grassland degradation causes a significant decrease in the inputs of plant of C, N, and P to the soil and results in decreased soil of C, N, and P accumulation (Zak et al 2003;De Deyn et al 2004;Li et al 2009;Harrison and Bardgett 2010). High plant diversity may produce high plant biomass and different root exudates, which, in turn, supports a greater diversity of decomposers, detritivores, and symbiotic microorganisms (Millard and Singh 2010;Eisenhauer et al 2012;Rzanny and Voigt 2012), promoting decomposition of organic matter and available nutrient supply, improving plant growth hormones, and maintaining grassland ecosystem dynamic stability (Millard and Singh 2010;Shi et al 2011). The effects of plant diversity and productivity on soil properties can persist for years, even if the plant species has disappeared.…”