Mycorrhizas in South American Anthropic Environments

The agricultural expansion has leaded to increase the irrigated cropland area and the use of fertilizers, resulting in water degradation, increased energy use, and common pollution. Of particular concern is the increased interest to reduce the environmental impacts of high quantities of water dedicated to irrigation by agricultural activities We are now truly recognizing the importance of sustainable measures in agriculture such as conservation of the vegetation cover and management approach to understand surface and deep soil responses to global change. The agroecology management based on key processes from natural ecosystems can help to solve some agricultural difficulties. Increasing studies on the Arbuscular mycorrhizal fungi (AMF) has showed their importance for soil ecology and studies on their biodiversity have spread in some agro-ecosystems such as corn and soybean monocultures. Therefore, it is needed to deeply study the mycorrhizal functions under global change. In this chapter, we examine the major developments and advances on mycorrhizal fungi based on recent research from South American countries. New reports on the occurrence of mycorrhizas in Amazonian dark earth, as well as the inoculum production of arbuscular mycorrhizal fungi native of soils under native forest covers, have resulted in a more detailed understanding of the soil biology from South America. Reports from Amazonian dark earth or “Terra preta do índio” soil has stimulated the use of biochar worldwide as a soil conditioner that can add value to non-harvested agricultural products and promote plant growth. Few reports from Brazil showed that the addition of inorganic fertilizer, compost and chicken manure resulted in increases in plant cover and plant species richness. In this sense, the biochar/mycorrhizae interactions also can be prioritized for sequestration of carbon in soils to contribute to climate change mitigation

Termite sensitivity to temperature affects global wood decay rates.

Deadwood is a large global carbon store with its store size partially determined by biotic decay. Microbial wood decay rates are known to respond to changing temperature and precipitation. Termites are also important decomposers in the tropics but are less well studied. An understanding of their climate sensitivities is needed to estimate climate change effects on wood carbon pools. Using data from 133 sites spanning six continents, we found that termite wood discovery and consumption were highly sensitive to temperature (with decay increasing >6.8 times per 10°C increase in temperature)-even more so than microbes. Termite decay effects were greatest in tropical seasonal forests, tropical savannas, and subtropical deserts. With tropicalization (i.e., warming shifts to tropical climates), termite wood decay will likely increase as termites access more of Earth's surface

Data from: Plasticity in root symbioses following shifts in soil nutrient availability during long-term ecosystem development

1. The vast majority of terrestrial plants form root symbioses with arbuscular mycorrhizal (AM) fungi to enhance nutrient (particularly phosphorus, P) acquisition, but some plant species also form dual symbioses involving ectomycorrhizal (ECM) fungi, with a subset of those also forming triple symbioses also involving dinitrogen (N2)-fixing bacteria. Whether these plants show plasticity in root symbioses to optimise nutrient acquisition depending on the type and strength of soil nutrient limitation (e.g., N vs. P) has been suggested, yet empirical evidence remains limited. Alternatively, the degree of investment or ‘preference’ in particular root symbioses might simply reflect differences in inoculum potential among soils of contrasting nutrient availability, reflecting adaptations of root symbionts to different edaphic conditions. 2. Here, we grew two co-occurring plant species forming triple (AM / ECM / N2-fixing; Acacia rostellifera) or dual (AM / ECM; Melaleuca systena) symbioses in soils of increasing age and contrasting nutrient availability from an Australian long-term soil chronosequence to disentangle the relative importance of abiotic factors (e.g., soil nutrient availability and stoichiometry) and biotic factors (e.g., soil inoculum potential) in determining root colonisation patterns and functional outcomes of these multiple root symbioses. 3. For both plant species, we found clear hump-shaped plant growth patterns along the pedogenesis-driven gradient in soil nutrient availability, with peak growth in intermediate-aged soils, while high levels of mycorrhizal colonisation by the ‘preferred’ root symbionts was maintained. We found large increases (540%) in foliar manganese concentrations with increasing soil age and declining P availability, suggesting that plants are also relying on the release of carboxylates to help acquire P in the most impoverished soils. Finally, we found that soil abiotic properties, such as strong differences in soil nutrient availabilities, are generally more important than soil inoculum potential in explaining these shifts in our plant and root responses. 4. Synthesis. Our study suggests that plants capable of forming multiple root symbioses show plasticity in their nutrient-acquisition strategies following shifts in soil nutrients during long-term ecosystem development, yet maintain a preference for certain root symbionts despite changes in soil microbial inoculum

Teste FunctionalEcology RawData FE-2013-00901_R1

Raw data from FE-2013-00901.R1 includes: plant growth, colonisation by mycorrhizal fungi, root intermingling in pots, and foliar nutrient levels

Appendix B. Equations and development of the temporal seed bank model.

Equations and development of the temporal seed bank model

Appendix A. ANOVA tables and unstandardized effect sizes.

ANOVA tables and unstandardized effect sizes

Table A1

GPS data of the 15 plots sampled within the three different dunes systems (Quindalup = Young, Spearwood = Middle and Bassendean = Old) of the Jurien Bay chronosequence (Zemunik et al. 2015)

Figure 2 RAxML_bipartitions_soilsamples.tre

Phylogenetic Maximum-Likelihood tree (RAxML) with accession numbers only of all AMF-OTUs detected in soil at the Jurien Bay chronosequence. The phylip file used for this phylogenetic tree is uploaded as ReadMe file