Soil and geography are more important determinants of indigenous arbuscular mycorrhizal communities than management practices in Swiss agricultural soils

Abstract

Arbuscular mycorrhizal fungi (AMF) are ubiquitous soil fungi, forming mutualistic symbiosis with a majority of terrestrial plant species. They are abundant in nearly all soils, less diverse than soil prokaryotes and other intensively studied soil organisms and thus are promising candidates for universal indicators of land management legacies and soil quality degradation. However, insufficient data on how the composition of indigenous AMF varies along soil and landscape gradients have hampered the definition of baselines and effect thresholds to date. Here, indigenous AMF communities in 154 agricultural soils collected across Switzerland were profiled by quantitative real-time PCR with taxon-specific markers for six widespread AMF species. To identify the key determinants of AMF community composition, the profiles were related to soil properties, land management and site geography. Our results indicate a number of well-supported dependencies between abundances of certain AMF taxa and soil properties such as pH, soil fertility and texture, and a surprising lack of effect of available soil phosphorus on the AMF community profiles. Site geography, especially the altitude and large geographical distance, strongly affected AMF communities. Unexpected was the apparent lack of a strong land management effect on the AMF communities as compared to the other predictors, which could be due to the rarity of highly intensive and unsustainable land management in Swiss agriculture. In spite of the extensive coverage of large geographical and soil gradients, we did not identify any taxon suitable as an indicator of land use among the six taxa we studied.

Could biological invasion by Cryptostegia madagascariensis alter the composition of the arbuscular mycorrhizal fungal community in semi-arid Brazil?

“…AMF species from Order Diversisporales (genus Acaulospora), and Gigasporales (genus Dentiscutata, Gigaspora, and Scutellospora) are common in semi-arid sites (Dandan & Zhiwei 2007;Silva et al 2014), and in acid soil with low phosphorous availability (Ramos et al 2008). However, disturbances and changes in soil properties, such as soil pH, total organic carbon and available phosphorous can be favorable for Glomerales species (Oehl et al 2010;Jansa et al 2014;Carneiro et al 2015). Therefore, changes in soil properties induced by the invasive plant may contribute to constrain the occurrence of some AMF species, reduce AMF sporulation, and decrease AMF diversity and AMF dominance (Tab.…”

Arbuscular mycorrhizal fungal community differences among European long-term observatories

“…As previously underlined by Jansa et al (2014), soil qual-ity, health, and management history are extremely important factors for understanding and supporting the sustainable use of soils, but they can be difficult to quantify or define func-tionally. AMF are important contributors to soil function in agricultural as well as natural contexts.…”

“…Apart from these specific environmental factors, direct land use-related circumstances, such as tillage (which in-creases soil disturbance) or grazing (which removes above-ground plant biomass), also have been suggested as drivers of AMF community composition (e.g., Helgason et al 1998;Oehl et al 2010;Schnoor et al 2011;Stockinger et al 2014;Valyi et al 2015). A high number of studies specifically have addressed the impact of agricultural practices and changes in land use on either the composition of AMF communities (e.g., van der Gast et al 2011;Lin et al 2012;Lumini et al 2010;Verbruggen et al 2012;Dai et al 2013;Hazard et al 2013;Morris et al 2013;Moora et al 2014;Xiang et al 2014;Valyi et al 2015) or individual taxa (Bainard et al 2014;Jansa et al 2014). Experimental studies, however, usually are confined to one or a few sites, and therefore may have facilitated the identification of effects of specific agricultural practices at the expense of visibility of other (independent) effects such as soil type and geography (Jansa et al 2014).…”

“…AMF are important contributors to soil function in agricultural as well as natural contexts. Due to the relatively low diversity of AMF taxa, different preferences of individual taxa for environmental properties, and their global distribu-tion, AMF therefore are promising candidates as bioindicators of land management legacies and soil quality degradation (Jansa et al 2014).…”

“…A high number of studies specifically have addressed the impact of agricultural practices and changes in land use on either the composition of AMF communities (e.g., van der Gast et al 2011;Lin et al 2012;Lumini et al 2010;Verbruggen et al 2012;Dai et al 2013;Hazard et al 2013;Morris et al 2013;Moora et al 2014;Xiang et al 2014;Valyi et al 2015) or individual taxa (Bainard et al 2014;Jansa et al 2014). Experimental studies, however, usually are confined to one or a few sites, and therefore may have facilitated the identification of effects of specific agricultural practices at the expense of visibility of other (independent) effects such as soil type and geography (Jansa et al 2014). Furthermore, to fully appreciate the extent of anthropogenic influence on AMF soil communities, the impact of management practicesshould be weighed against the background of the normal (e.g., seasonal, plant growth-related) fluctuations of AMF taxa un-der field conditions (Pereira et al 2013).…”