The benefits of the arbuscular mycorrhizal (AM) symbiosis between plants and fungi are modulated by the functional characteristics of both partners. However, it is unknown to what extent functionally distinct groups of plants naturally associate with different AM fungi.We reanalysed 14 high-throughput sequencing data sets describing AM fungal communities associating with plant individuals (2427) belonging to 297 species. We examined how root-associating AM fungal communities varied between plants with different growth forms, photosynthetic pathways, CSR (competitor, stress-tolerator, ruderal) strategies, mycorrhizal statuses and N-fixing statuses.AM fungal community composition differed in relation to all studied plant functional groups. Grasses, C 4 and nonruderal plants were characterised by high AM fungal alpha diversity, while C 4 , ruderal and obligately mycorrhizal plants were characterised by high beta diversity. The phylogenetic diversity of AM fungi, a potential surrogate for functional diversity, was higher among forbs than other plant growth forms. Putatively ruderal (previously cultured) AM fungi were disproportionately associated with forbs and ruderal plants. There was phylogenetic correlation among AM fungi in the degree of association with different plant growth forms and photosynthetic pathways.Associated AM fungal communities constitute an important component of plant ecological strategies. Functionally different plants associate with distinct AM fungal communities, linking mycorrhizal associations with functional diversity in ecosystems.

Soil processes such as decomposition are mainly performed by soil biota. Although soils worldwide are extremely biodiverse, the relationship between decomposers (fauna and microorganisms), and ecosystem function is poorly understood. Collembola are abundant and ubiquitous microarthropods that are found in terrestrial ecosystems. They can affect the amount of biomass and the activity of microbial communities, either directly through selectively feeding on fungi and bacteria, or indirectly by dissemination of microbial propagules, and the alteration of nutrient availability. However, despite the functional role they play in belowground food webs, the interactions between natural assemblages of soil microbes and Collembola receive little attention. This study, conducted in microcosm conditions, examines the effects of two distinct natural assemblages of functional groups of Collembola (ep-and euedaphic) upon microbial communities using PLFA markers and their associated soil functions (e.g., enzymatic activities and C mineralization rate) over a 2-month period. Our principal objective was to determine whether different functional groups of Collembola had varying effects on microbial soil community abundance, structure and activity, resulting in potentially important effects on ecosystem processes. Our findings show that the interactions of the functional groups of Collembola with microbial communities vary significantly whether they are alone or combined. A distinct response in the composition of the microbial communities was found at the end of the 2-month period. The communities were significantly different from each other in terms of PLFA marker composition. We found that the epedaphic species were related to and promoted Gram+ bacteria whereas euedaphic species were related to Gram-bacterial markers. This had further repercussions on soil function, such as nutrient recycling. Combining both functional groups did not lead to a complementary effect on soil microbial properties, with a drastically different outcome between the first and the second month of the experiment. Additional research dealing with the interactions between decomposers using natural assemblages will help to predict the functional outcomes of soil biota structure and composition.

No abstract

Soil life supports the functioning and biodiversity of terrestrial ecosystems. Springtails (Collembola) are among the most abundant soil arthropods regulating soil fertility and flow of energy through above- and belowground food webs. However, the global distribution of springtail diversity and density, and how these relate to energy fluxes remains unknown. Here, using a global dataset representing 2470 sites, we estimate the total soil springtail biomass at 27.5 megatons carbon, which is threefold higher than wild terrestrial vertebrates, and record peak densities up to 2 million individuals per square meter in the tundra. Despite a 20-fold biomass difference between the tundra and the tropics, springtail energy use (community metabolism) remains similar across the latitudinal gradient, owing to the changes in temperature with latitude. Neither springtail density nor community metabolism is predicted by local species richness, which is high in the tropics, but comparably high in some temperate forests and even tundra. Changes in springtail activity may emerge from latitudinal gradients in temperature, predation and resource limitation in soil communities. Contrasting relationships of biomass, diversity and activity of springtail communities with temperature suggest that climate warming will alter fundamental soil biodiversity metrics in different directions, potentially restructuring terrestrial food webs and affecting soil functioning.

RESUMOA qualidade do solo em plantio direto está relacionada ao sistema de culturas e pode ser avaliada pelo teor de matéria orgânica particulada (>53 µ µ µ µ µm), em razão da funcionalidade que essa fração proporciona ao solo e à sua sensibilidade às diferenças de manejo. Visando estudar a qualidade do solo em sistemas de culturas em plantio direto, este trabalho foi conduzido em experimento de longa duração (21 anos) em Latossolo Vermelho distrófico típico nos Campos Gerais do Paraná. Seis sistemas de culturas foram avaliados, em que trigo-TR (Triticum aestivum L.), soja-SO (Glycine max L.), milho-MI (Zea mays L.), aveia-preta-AV, para cobertura (Avena strigosa Schreb.), ervilhaca-ER, para cobertura (Vicia villosa Roth); azevém-AZ, para feno (Lolium multiflorum Lam.); ou alfafa-AL, para feno (Medicago sativa L.) compuseram os seguintes sistemas: TR-SO (referência), ER-MI-AV-SO-TR-SO, ER-MI-TR-SO, AV-MI-TR-SO, AZ-MI-AZ-SO e AL-MI (milho a cada três anos). Os estoques de carbono orgânico total (COT), nitrogênio total (NT) e de C e N na matéria orgânica (MO) particulada (>53 µm) e associada aos minerais (<53 µm) foram determinados em 0-5, 5-10 e 10-20 cm. O sistema semiperene AL-MI apresentou os maiores estoques de COT e NT na camada de 0-20 cm (63,6 Mg ha -1 COT e 4,6 Mg ha -1 NT), com incrementos anuais de 0,23 Mg ha -1 COT e 0,03 Mg ha -1 NT, em relação ao sistema TR-SO. O sistema AL-MI também teve os maiores estoques de C e N na MO particulada nessa camada (12,5 e 0,91 Mg ha -1 , respectivamente), por causa da maior adição de fitomassa pelas raízes e a proteção física dos resíduos orgânicos. Os menores estoques de COT e NT na camada 0-20 cm ocorreram no sistema ER-MI-TR-SO (57,8 Mg ha -1 COT e 4,03 Mg ha -1 NT), sem apresentar incremento anual em relação ao sistema TR-SO. Os estoques de C e N na MO particulada foram de 10,4 e 0,67 Mg ha -1