【土壤原生动物群落】Scott T Bates Jose C Clemente Gilberto E Flores William Anthony Walters Laura Wegener Parfrey Rob Knight and Noah Fierer.Global biogeography of highly diverse protistan communities in soil. The ISME Journal (2013) 7 652–659; doi:10.1038-ismej.2012.147

Abstract

Protists are ubiquitous members of soil microbial communities but the structure of these communities and the factors that influence their diversity are poorly understood. We used barcoded pyrosequencing to survey comprehensively the diversity of soil protists from 40 sites across a broad geographic range that represent a variety of biome types from tropical forests to deserts. In addition to taxa known to be dominant in soil including Cercozoa and Ciliophora we found high relative abundances of groups such as Apicomplexa and Dinophyceae that have not previously been recognized as being important components of soil microbial communities. Soil protistan communities were highly diverse approaching the extreme diversity of their bacterial counterparts across the same sites. Like bacterial taxa protistan taxa were not globally distributed and the composition of these communities diverged considerably across large geographic distances. However soil protistan and bacterial communities exhibit very different global-scale biogeographical patterns with protistan communities strongly structured by climatic conditions that regulate annual soil moisture availability.

【丛枝菌根真菌的群落组成】Christina Hazard Paul Gosling Christopher J van der Gast Derek T Mitchell Fiona M Doohan and Gary D Bending. The role of local environment and geographical distance in determining community composition of arbuscular mycorrhizal fungi at the landscape scale. The ISME Journal (2013) 7 498–508; doi:10.1038-ismej.2012.127

Abstract

Arbuscular fungi have a major role in directing the functioning of terrestrial ecosystems yet little is known about their biogeographical distribution. The Baas-Becking hypothesis (‘everything is everywhere but the environment selects’) was tested by investigating the distribution of arbuscular mycorrhizal fungi (AMF) at the landscape scale and the influence of environmental factors and geographical distance in determining community composition. AMF communities in Trifolium repens and Lolium perenne roots were assessed in 40 geographically dispersed sites in Ireland representing different land uses and soil types. Field sampling and laboratory bioassays were used with AMF communities characterised using 18S rRNA terminal-restriction fragment length polymorphism. Landscape-scale distribution of AMF was driven by the local environment. AMF community composition was influenced by abiotic variables (pH rainfall and soil type) but not land use or geographical distance. Trifolium repens and L. perenne supported contrasting communities of AMF and the communities colonising each plant species were consistent across pasture habitats and over distance. Furthermore L. perenne AMF communities grouped by soil type within pasture habitats. This is the largest and most comprehensive study that has investigated the landscape-scale distribution of AMF. Our findings support the Baas-Becking hypothesis at the landscape scale and demonstrate the strong influence the local environment has on determining AMF community composition.

【真菌群落的凋落物分解】Jana&nbs